Team:SDU-Denmark/test

PowerLeaf - a bacterial solar battery


ENERGY MADE BEAUTIFUL

Abstract

The PowerLeaf introduces a novel solution for long-term storage of solar energy, thus becoming an alternative to solar cells. This is accomplished without the use of environmentally harmful resources. The device is designed to resemble a plant leaf aimed to provide a nature-in-city ambience. This hypothetical implementation of the PowerLeaf in an urban environment was developed through public engagement and collaboration. The bacterial solar battery is composed of an energy storing unit and an energy converting unit. The energy storing unit is defined by a genetically engineered Escherichia coli that fixates carbon dioxide into the chemically stable polymer cellulose. A light-dependant system activates dormancy during nighttime to reduce energy lost by metabolism. The energy converting unit uses genetically engineered Escherichia coli to consume the stored cellulose. Retrieved electrons are transferred by optimised nanowires to an anode resulting in an electrical current.

A green project, a green wiki and winners of iGEM goes green! Green just got greener.

Introduction

Welcome to our wiki! We are the iGEMteam from the University of Southern Denmark. We have been waiting in great anticipation for the chance to tell you our story.
Our adventure began with a meeting between strangers from eight different studies. Despite our different backgrounds, we had one thing in common; a shared interest in synthetic biology. Soon after this first meeting, we were herded off to a weekend in a cottage - far away from our regular lives. The cottage was a place to bond and discuss project ideas. It immediately became apparent that being an interdisciplinary team was going to be our strength. Each member had unique qualities that enabled them to efficiently tackle different aspects of the iGEM competition. So, we made it our goal to take advantage of these qualities.
We decided to make a proof-of-concept project. Specifically, we wanted to use bacteria as a novel and greener solution for solar energy storage. This project was later dubbed the PowerLeaf – a bacterial solar battery.
Since it is a one-page wiki you can just keep on scrolling, and you will be taken on a journey through our iGEM experience.

Achievements

Bronze Medal Requirements 4/4


Register and attend – Register and attend – Our team applied 2017-03-30 and got accepted 2017-05-04. We had an amazing summer and are looking forward to attend the Giant Jamboree!
Meet all the deliverables requirements – You are reading the team wiki now, so that’s one cat in the bag. You can find all attributions made to the project in the credits section of the wiki here. The team poster and team presentation are ready to be presented at the Giant Jamboree. We also filled the safety form, the judging form and all our parts were registered and submitted in time.
Clearly state the Attributions – All attributions made to our project have been clearly credited in the credits section.
Improve and/or characterize an existing Biobrick Part or Device – Pending

Silver Medal Requirements 3/3


Validated part/contribution – Pending
Collaboration – We have collaborated with several teams throughout our project by taking part in discussions, meetups, answering questionnaires - we even hosted our first meetup for our fellow Danish teams. You will get to read all about all of this in the credits section.
Human Practices – Our philosopher, historian and biologist have discussed the ethical and educational aspects of our project in great detail. In extension to their work, we have been working extensively with public engagement and education.

Gold Medal Requirements 2/4


Integrated Human Practices – Regarding the development and implementation of the device, we reached out to and remained in contact with city planners from our hometown throughout our project. This regarded advice and conversations on anything from the possible design, value, safety, use, placement and plastic type of our device. We also made sure to integrate the findings of said conversations into our overall project. Additionally we focused on demonstrating this process on our wiki; in order to inspire future iGEM teams.
Improve a previous part or project – Requirement not fulfilled.
Model your project – Through extensive modelling we have learned that it is possible to regulate bacterial dormancy. However, the modelling showed that it would be inadequate to only regulate RelE (toxin), as this would make the bacteria unable to exit dormancy. To make them enter dormancy, it would require tight regulation of the RelB (anti-toxin). This information was used in the approach of the light-dependent dormancy system.
Demonstrate your work – Requirement not fulfilled.

World Situation

A Global Problem

In the world of today, it is becoming increasingly important to ensure a sustainable future. Not just for our generation, but especially for the generations to come, as their possibilities should not be limited by our choices. Our solution, is the development of a green and renewable technology, which offers new advantages to the field of sustainable energy. There are currently certain limitations to the existing options for renewable energy; the intermittency and the diluteness problem. The intermittency problem describes the discontinuous energy production, along with inefficient storage. Whereas the diluteness problem is characterised as the resource demanding production of technical devices, such as solar cells and batteries. Meaning that a lack of resources eventually would eliminate the current forms of green technology. As such, we need to introduce a new and sustainable approach to green energy, to ensure the continuation of our beautiful world for the coming generations.

In a Local Environment

We are a team of young adults raised with an awareness of climate changes and the potential limitations to our ways of life. As a generation that appreciates open source and shared information, we have been encouraged to constantly challenge the ideas of yesterday. With this in mind, we decided the best solution to the eventual energy crisis would be to seek out experts and the general public, even children, in order to rethink the current notion; that the only way to save our planet is to compromise our living standards.
Fortunately, we learned through interaction with local agents that a great deal of people share our belief; that we ought to pursue the development of low energy cities with a high quality of life. In fact, we even discovered that our own hometown Odense wants to be the greenest, most renewable city in Denmark by 2050. Odense municipality’s website, regarding their politics on the current climate changes.
In the pursuit of this goal, we took on the challenge of creating a truly green solution, which would provide an environmental friendly source of energy.
Please keep scrolling if you wish to read more about our solution , or go straight to bioethics if you are curious why we not only could, but ought to do something about the current energy crisis.

Inspiration

Our early ideas were reviewed after attending the Danish Science Festival, where we met several young minds with creative and inspiring ideas. The children would come to our workshop with their parents to learn about bacteria, the history of GMO, ethics and iGEM. They attended our “Draw-a-Bacteria”-competition, where they designed their own bacteria, some with detailed stories. From this, the children would teach us a thing or two about the endless possibilities of GMO.



See a selection of their amazing drawings here.

Our Solution

Our Solution

The bacterial solar battery we envision, is composed of an energy storing and an energy converting unit. The energy storing unit is defined by a genetically engineered Escherichia coli (E. coli). The E. coli uses solar energy for ATP production to fixate carbon dioxide into the chemically stable polymer cellulose, which essentially is the battery. A light sensing system activates dormancy during nighttime, in order to reduce energy lost by metabolism. The energy converting unit uses genetically engineered E. coli to consume the stored cellulose, by using an inducible switch. Retrieved electrons are transferred by optimised nanowires to an anode, resulting in an electrical current. The complete system will be combined into a single device containing a compartment for each of the two units. Details about the construction and device will be discussed in the Integrated Practices section.
The device was originally designed to resemble a plant leaf aimed to provide a nature-in-city ambience. This hypothetical implementation of the PowerLeaf in an urban environment was developed through creative thinking, public engagement, and collaborations. We worked with local city planners from our hometown, in order to advance on this design and to provide other, changeable, designs.
Our vision was clear and ambitions were high, probably too high, considering the limited timeframe. So, at an early stage, we decided to focus on the following features:

  1. Light-dependent dormancy system
  2. Converting CO2 to glucose
  3. Biosynthesis and secretion of cellulose produced from glucose
  4. Converting cellulose to glucose
  5. Extracellular electron transfer

It will then be up to prospective iGEM teams to continue on the development of the PowerLeaf. We would love to see our project become a reality one day hence we have created a special page for future iGEM teams. This page includes suggestions for further development of the project.

Project & Results

We have throughout the project worked on the development of 2 units for our device, an energy storing and an energy converting unit. Each of the systems we worked on for the units can be seen here:
Energy storing (E. Coli)

  • Light-dependent dormancy system

  • Carbon fixation

  • Cellulose biosynthesis and secretion


Energy converting (G. Sulfurreducens)

  • Breakdown of cellulose

  • Extracellular electron transfer

Once you reach each of the 5 systems in the 'Project Design'-section, you will first be given a short introduction to the underlying theory, which you will be able to expand on, by pressing “read more”. After the theory, you will be given the approach used in each of the respective systems for the project. Before continuing on to the next system. To make things easier on you, we have developed icons to each of the above systems which will be used throughout the rest of the wiki.

Project Design








Dormancy System

Theory


Cyanobacteria contain signal transduction systems, thereby making them capable of sensing and responding to light Bussell AN, Kehoe DM. Control of a four-color sensing photoreceptor by a two-color sensing photoreceptor reveals complex light regulation in cyanobacteria. Proceedings of the National Academy of Sciences of the United States of America. 2013;110(31):12834-9.. This ability gives the organisms the opportunity, to adapt and optimize their metabolism to a circadian rhythm. Photoreceptors in the plasma membrane, of which phytochromes are especially abundant and well described, are responsible for this property Vierstra RD, Davis SJ. Bacteriophytochromes: new tools for understanding phytochrome signal transduction. Seminars in cell & developmental biology. 2000;11(6):511-21.. In 2004, the UT Austin iGEM team made a light response system consisting of a photoreceptor combined with an intracellular indigenous regulator system Levskaya A, Chevalier AA, Tabor JJ, Simpson ZB, Lavery LA, Levy M, et al. Synthetic biology: engineering Escherichia coli to see light. Nature. 2005;438(7067):441-2.. EnvZ and OmpR makes up the two-component system naturally found in E. coli. The photoreceptor known as Cph1 was isolated from the cyanobacteria Synechocytis PCC6803. Cph1 has functional combination sites, which combined with the kinase EnvZ forms a two-domain receptor, known as Cph8. Activation of Cph8 is mediated by the chromophore phycocyanobilin, PCB that is sensitive to red light with maximal absorbance at 662 nm Lamparter T, Esteban B, Hughes J. Phytochrome Cph1 from the cyanobacterium Synechocystis PCC6803. Purification, assembly, and quaternary structure. European journal of biochemistry. 2001;268(17):4720-30..
When not exposed to light, PCB activates the phytochrome Cph1, thereby promoting kinase activity through the EnvZ kinase. When the transcription factor OmpR is phosphorylated by EnvZ, expression of genes regulated by the OmpR-regulated promoter is initiated. Excitation of PCB by red light results in a situation where the transcription factor OmpR is not regulated. The absence of phosphorylated OmpR leads to no activation of the OmpR-regulated promoter, thereby preventing gene expression.



Using the photocontrol device to control a toxin-antitoxin system is a system composed of two gene products, of which one specifies a cell toxin and the other an antitoxin, which neutralizes the toxic effect caused by the toxin. In E. coli K-12 the cytotoxin RelE and antitoxin RelB comprise such a system Gotfredsen M, Gerdes K. The Escherichia coli relBE genes belong to a new toxin-antitoxin gene family. Molecular microbiology. 1998;29(4):1065-76.. Expression of the cytotoxin RelE inhibits translation in the cells, due to its ability to cleave mRNA found in the A-site of the ribosome. RelB neutralizes the toxic effect of RelE through interaction between the two proteins. Whether the cell lie dormant in response to expression of RelE depends on the ratio of antitoxin RelB and RelE present in the cell. Several studies have shown that RelB and RelE form a complex with RelB:RelE stoichiometry of 2:1 Overgaard M, Borch J, Gerdes K. RelB and RelE of Escherichia coli form a tight complex that represses transcription via the ribbon-helix-helix motif in RelB. Journal of molecular biology. 2009;394(2):183-96.Overgaard M, Borch J, Jorgensen MG, Gerdes K. Messenger RNA interferase RelE controls relBE transcription by conditional cooperativity. Molecular microbiology. 2008;69(4):841-57.. When the RelB:RelE stoichiometric-ratio is lowered to 1:1, studies show that RelB is not able to protect the cells against the RelE-caused translational inhibition Overgaard M, Borch J, Jorgensen MG, Gerdes K. Messenger RNA interferase RelE controls relBE transcription by conditional cooperativity. Molecular microbiology. 2008;69(4):841-57.. For further information about the theory behind the light-dependent dormancy system, read here.


Approach


In 2004 the Austen and UCSF iGEM team created a device sensitive to light, laying the foundation for the Coliroid project. In this project, the system is combined with the RelE-RelB toxin-antitoxin system in the endeavour to mediate light-dependent dormancy in bacteria. As tight regulation is required for the RelE-RelB system [2], modelling of the toxin-antitoxin system is essential. The impact of different RelE-RelB expression levels was simulated by modelling. Using the results obtained by modelling, a hypothetical working system-design was devised.
On basis of the modulated system, the potential of different vectors and promoters in various combinations was tested. This constitutes the foundation for how the design of the light induced dormancy system in E. coli has been optimized and the final approach shaped. Ultimately, the light-dependent dormancy system, which is illustrated in figure #, was composed of the following parts:

  • The photocontrol device controlled by the PenI-regulated promoter, BBa_R0074, on a high copy vector.
  • The antitoxin RelB controlled by pBAD, BBa_K2449031, on a low copy vector.
  • The toxin RelE controlled by the OmpR-regulated promoter, BBa_R0082, on either a low copy vector or the chromosome.

For further information about our approach, read here.


Modelling


Modelling of the RelE-RelB System is Essential to Avoid Irrevocable Dormancy
Controllable dormancy is a feature that holds the potential to be applied in many different situations. Inducing dormancy and bringing the bacteria back to a metabolic active state is like balancing on a tightrope. To establish the basis of the future implementations, the properties of this system would have to be investigated further. In an endeavour to provide this, stochastic modelling was performed in an attempt to prognosticate the system and simulate the interactions between the toxin and antitoxin. To consolidate the model, the capacity of the toxin-antitoxin system was assessed in an experiment. By manually regulating the RelB expression, the controllability of the dormancy system was studied. The gillespie algorithm was utilised to model the interactions of the toxin and antitoxin. The toxin RelE is inhibited by the antitoxin RelB through complex formation, and both interact with their promoter in a feedback mechanism. You can read more about the model here .



It was deduced that when enhanced RelE production is implemented as a tool to make the bacteria dormant, the effect come easily. However, an additional implementation of RelB expression is found necessary to ensure that the bacteria enter an active state again. The model showed that the system is sensitive to the RelE:RelB ratio as well as the total production of toxin. Implementation, with production rates in the vicinity of 50 and 35 molecules pr. min for RelB and RelE respectively, yields an acceptable effect: The bacteria lay dormant within the computed time, and re-enter an active state quickly. From the sensitivity to RelB production and RelE-RelB on activation time, it is evident that it will be challenging to implement an optimised system. You can see the full results here.


Carbon Fixation

Theory


Carbon fixation in autotrophic organisms is responsible for the net fixation of 7×1016 g carbon annually [kilde 2]. Six different pathways related to carbon fixation have been discovered, but the most widespread of these, is the Calvin-Benson-Bassham (CBB) cycle found in photosynthetic eukaryotes, e.g. plants and algae, as well as in photo- and chemosynthetic bacteria [kilde 6]. Out of the eleven enzymes needed for the Calvin cycle, only three are heterologous to E. coli, namely; ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo), sedoheptulose-1,7-bisphosphatase (SBPase) and phosphoribulokinase (PRK). By the concurrent heterologous expression of the three genes encoding these enzymes, E. coli can be engineered to perform the full Calvin cycle.



The carboxysome is a microcompartment utilised by many chemoautotrophic bacteria, including cyanobacteria, as a CO2 accumulating mechanism to increase carbon fixation efficiency. This organelle-like polyhedral body is able to increase the internal concentrations of inorganic carbon by 4000-fold compared to the external concentration [kilde 8]. One type of carboxysome, is the ɑ-carboxysome, which consists of a proteinaceous outer shell composed of six different shell proteins designated CsoS1ABCD and CsoS4AB. This shell encloses RuBisCo, the shell associated protein (CsoS2), and the enzyme carbonic anhydrase (CsoS3). In the proteobacteria Halothiobacillus neapolitanus, these genes are clustered into the cso operon. The carbonic anhydrase converts HCO3-, which diffuses passively into the carboxysome, to CO2, thereby driving the continued diffusion of HCO3- into the microcompartment [kilde 8]. The increased CO2 concentration in the vicinity of RuBisCo increases the rate of carbon fixation by saturating the RuBisCo enzyme and increasing the CO2 to O2 ratio, enabling carboxylation to dominate over oxygenation [kilde 8]. The shell associated protein is essential for the biogenesis of the ɑ-carboxysome [kilde 12].



For the Calvin cycle to proceed, energy in the form of ATP and electrons carried by NADPH are required. The photosystems are complexes in photosynthesising organisms that can supply this by photophosphorylation. To engineer E. coli to do photosynthesis, 13 genes is needed for the assembly of chlorophyll a and 17 genes for the assembly of photosystem II, which needs to be heterogeneously expressed. An alternative process, in which a diverse array of phototrophic bacteria and archaea harvest energy from light, is through a retinal-containing protein called proteorhodopsin, which catalyses the light-activated proton efflux across the cell membrane and thereby drive ATP synthesis. Opposed to the photosystems, the proteorhodopsin is anoxygenic and generates no NADPH, which is crucial for the Calvin cycle to proceed [kilde 21]. For further information about the theory behind the carbon fixation, read here.


Approach


In order to engineer E. coli in the outer chamber to turn atmospheric CO2 into cellulose, the carbon first needs to be fixated by the bacteria. This requires the heterologous expression of the genes encoding the three enzymes RuBisCo, SBPase, and PRK. Furthermore, the implementation of the carboxysome from the cso operon can increase the levels of carbon fixation. The 2014 Bielefeld iGEM team had worked with a similar approach in their project. In an endeavour to optimise the carbon fixation process, our project build upon their experiences. The assembly of the individual parts into a composite part, BBa_K2449030, was achieved, however, the cloning of these parts with a promoter emerged problematic. Consequently, it was decided to prioritise other aspects of the project and therefore keep this part theoretical henceforth. For further information about our approach, read here.


Cellulose Biosynthesis

Theory


Bacterial cellulose is one of the most abundant biopolymers produced by different species of gram-negative bacteria, especially by Acetobactors. Glucoacetobacter xylinus is a bacterial species, which produces cellulose in large quantities of high quality [1]. Cellulose is produced from the resource glucose-6-phosphate. This phosphorylated glucose is a key intermediate in the core carbon metabolism of bacteria given its importance in glycolysis, gluconeogenesis and pentose phosphate pathway [2]. Even though the pathway, where glucose and glucose-6-phosphate is converted into cellulose, only includes few steps, it requires a great amount of energy. Not only does the cell spend energy on forming UDP-glucose for cellulose biosynthesis, it also uses glucose, which otherwise would have contributed to generation of ATP [3].
The ability for G. xylinus to produce cellulose nanofibers from UDP-glucose, crystallize, and secrete it, is controlled by genes in the Acetobacter cellulose synthase (acs) operon acsABCD. This operon encodes four different proteins: AcsA, AcsB, AcsC and AcsD. A dimer, known as AcsAB, is formed by a catalytic domain, AcsA, and a regulatory domain, AcsB. This dimer is responsible for synthesising the cellulose nanofibers from UDP-glucose, whereas AcsC and AcsD secretes cellulose and forms an interconnected cellulose pellicle around the cells [6], as illustrated in figure #.



Other genera, including some E. coli strains, secrete cellulose as a component of their biofilm. Even though cellulose biosynthesis is intrinsic to E. coli, the quantity of the production is incomparable to cellulose biosynthesis in G. xylinus. Indigenously, E. coli is not capable of degrading cellulose into a metabolisable energy source [4]. However, if this structural and water-holding polymer is enzymatically degraded, first into cellobiose and then to glucose residues, the cellulose polymer is a potent source of energy [5].

Approach


To link the two bacterial compartments of the PowerLeaf, an efficient way to store the harvested energy was required. Research led to the finding that storing the chemical energy in cellulose would be a suitable approach, since this is a polysaccharide that bacteria normally are unable to degrade [1]. After looking into earlier iGEM projects it was found that the 2014 project Aqualose from Imperial College London, had worked with optimisation of cellulose biosynthesis in E. coli. Our aim was to enhance cellulose biosynthesis in E. coli MG1655, which naturally secretes small amounts of cellulose as a part of its biofilm [2]. This would be achieved by the cloning of plasmids containing the cellulose synthase operon acsABCD, utilising the two parts BBa_K1321334 and BBa_K1321335, constructed by Imperial College London 2014. This would enhance the cellulose biosynthesis and thereby optimise the energy outcome of the entire system in our project. Due to cloning difficulties, it was decided to prioritise other aspects of the project and therefore keep this part theoretical henceforth. For further information about the cellulose biosynthesis approach, read here.


Breakdown of Cellulose

Theory


Cellulose is a natural biopolymer used for a huge variety of biological purposes. It is most commonly found in plants, where it serves as the main structural component. Since plants are primary producers, many organisms of the Earth’s ecosystems have adapted accordingly [kilde 4]. One of the key evolutionary features for the primary consumers, was the development of the ability to degrade cellulose into glucose, which could then be used as a cellular fuel. A simple organism, able to efficiently do so, is the Cellumonas fimi, which converts cellulose to glucose in a two-step process, with cellobiose as the intermediate [kilde 7].

Breakdown of Cellulose to Cellobiose
Cellulose is a long polysaccharide consisting of β-1,4 linked D-glucose units. Many organisms, including E. coli, lack the enzymes able to degrade these strong β-linkages. To overcome this, the C. fimi developed two cellulases, namely the endo-β-1,4-glucanase and exo-β-1,4-glucanase, respectively encoded by the cenA and cex genes [kilde 7]. The endoglucanase is able to randomly degrade the amorphous structure of cellulose, thereby allowing the exoglucanase to cleave the β-1,4 linkages at every other D-glucose unit. Thus disaccharides are released in the form of cellobiose [kilde 8], as illustrated in figure #. Cellulose itself is too large to be transported across the bacterial cell membrane. Therefore, the breakdown of cellulose into cellobiose must take place in the extracellular fluid.


The α-Hemolysin Transport System
The ɑ-hemolysin transport system is an ABC transporter complex, consisting of three proteins, namely the outer membrane protein TolC, Hemolysin B (HlyB), and Hemolysin D (HlyD) [kilde 3]. The ABC transporter complex effectively transports intracellular Hemolysin A (HlyA) to the extracellular fluid. Utilising a linker peptide, the protein of interest can be fused with HlyA. Once a protein is HlyA-tagged, it can be recognized by the ATP-binding cassette HlyB, which will initiate transportation of the HlyA-tagged protein to the extracellular fluid, as seen in figure # [kilde 3, kilde 6].


Uptake of Cellobiose
While cellulose is too large to be pass the cell membrane, transportation of cellobiose is a common feature found in many organisms. An example is E. coli, which utilises the membrane protein lactose permease (LacY) [kilde 5]. In the cytosol, cellobiose is enzymatically catabolised.

Breakdown of Cellobiose to Glucose
Through evolutionary events, many organisms have developed the ability to express enzymes, capable of breaking the β-linkage in cellobiose. E. coli expresses the periplasmic β-glucosidase encoded by the bglX gene, which is known to have said feature, by hydrolysing the cellobiose β-linkage[kilde 1]. Saccharophagus degradans expresses a different enzyme, which efficiently cleaves the β-linkage in cellobiose, namely cellobiose phosphorylase encoded by the cep94A gene. This enzyme phosphorylates the cellobiose at its β-linkage, resulting in the degradation of cellobiose to D-glucose and α-D-glucose-1-phosphate [kilde 5], as seen in figure #.


Approach


Cellulose to Cellobiose
In the endeavour to engineer E. coli to utilise cellulose as it’s only carbon source, inspiration was drawn from the Edinburgh 2008 iGEM team project, who developed two BioBricks containing the cenA and cex genes. In this project, the α-hemolysin transport system was utilised by creating HlyA-tagged endo- and exo-β-1,4-glucanase, using a peptide linker. To implement this system in E. coli, heterogeneous expression of hlyB, hlyD, cenA-hlyA and cex-hlyA was required.
To achieve this, DNA synthesis of cenA and cex was ordered, each tagged with HlyA. The genes encoding HlyB and HlyD were retrieved from the part BBa_K1166002 by phusion PCR. Using the resulting PCR product, the following construct was composed for the degradation of cellulose into cellobiose, as illustrated on figure #.



Cellulose to Cellobiose
The Edinburgh 2011 iGEM team team created a BioBrick encoding periplasmic β-glucosidase endogenous to E. coli, proposed to increase its efficiency at degrading cellobiose to glucose. However, it seems that the enzymatic activity of bglX has faded as a result of evolution, rendering E. coli incapable of surviving solely on cellobiose. So even though E. coli can absorp cellobiose, it is not able to survive with this as its only carbon source.
To solve this issue, we decided to synthesise a cep94A Biobrick, intended to make E. coli capable of effectively surviving on cellobiose. To achieve this we composed the following construct:



Extracellular Electron Transfer

Theory


Microbial Fuel Cell
Electrochemical devices such as batteries and fuel cells are broadly used in electronics to convert chemical energy into electrical energy. A Microbial Fuel Cell (MFC) is an open system electrochemical device, consisting of two chambers, an anode chamber and a cathode chamber, separated by a proton exchange membrane as illustrated in figure y. Both the anode and the cathode in a MFC can use various forms of graphite as the base material. In the anode chamber of a MFC, microbes are utilised as catalysts to convert organic matter into metabolic products, protons and electrons [kilde 8]. This is carried out through metabolic pathways such as glycolysis, to generate needed ATP to maintain cellular life. This metabolic pathway also generates a release of electrons carried by NAD+ in its reduced form NADH.



Under aerobic conditions, the generated NADH will deliver its electron as part of the electron transfer chain, to return to its oxidised form NAD+. Under anaerobic conditions the electron transport chain will not be able to continue, which will cause the generated NADH to accumulate. As a consequence of accumulated NADH, the concentration of available NAD+ for glycolysis will decrease. This will drive the cell to carry out other metabolic pathways, such as fermentation, in order to maintain its ATP levels. Instead the accumulating NADH generated under anaerobic conditions, can be utilised to drive an electrical current by depositing the retrieved electrons to an anode coupled with an appropriate cathode. The cathode catalyst in a MFC will usually catalyse the reaction of 4 H+ + 2 O2 à H2O. The transfer of electrons from NADH to the anode can be executed in three different ways as shown in figure x; redox shuttles, direct contact electron transfer, and bacterial nanowires [kilde 7][kilde 8].



The redox shuttles use extracellular electron mediators, which hold the advantage of not being limited by the surface area of the anode. However, it is restricted by the slow diffusion of the extracellular mediators. The direct contact electron transfer, in reverse to the redox shuttles, is strongly limited by the surface area of the anode, but the membrane bound cytochromes in direct contact with the anode, rapidly delivers the electrons. Bacterial nanowires are known to efficiently transfer electrons, much like the direct contact electron transfer. However, bacterial nanowires are not as strictly limited by the surface area of the anode as the direct contact electron transfer is. This is due to bacterial nanowires ability to form complex networks of interacting nanowires in biofilm, to efficiently transfer electrons from distant microbes all the way to the anode using this network. [kilde 8]


Bacterial Nanowires
Nanowires are long electrically conductive pili found on the surface of various microorganisms, such as the metal reducing Geobacter sulfurreducens. G. sulfurreducens utilises nanowires to transfer accumulating electrons retrieved from metabolism, to metals in the nearby environment [kilde 3]. G. sulfurreducens is strictly anaerobic, as it would not be able to transfer its electrons to the environment in the presence of the highly reducing oxygen. Nanowires found in G. sulfurreducens is a type IV pilin polymer chain composed of pilA monomers, which can reach nearly 10 mm in length [kilde 4]. The proteins required for the effective transfer of electrons by nanowires is a complex and poorly understood system, which involves a long series of c-type cytochromes [kilde 6].



The electrical conductivity of the nanowires in G. sulfurreducens can be optimised by exchanging endogenous pilA with heterologous pilA rich in aromatic amino acids. Tan Yang et. al [kilde 1] did an exchange like this by heterogeneously expressing pilA from G. metallireducens, which proved to increase the electrical conductivity of the G. sulfurreducens recombinant by a 5000-fold. This optimisation can be helpful in the development of highly efficient bacterial strains for MFCs. With the intention of optimising a MFC, G. sulfurreducens is a lot easier to work with than G. metallireducens [kilde 1].


Approach


Originally, we wanted to implement bacterial nanowires from G. sulfurreducens into E. coli. Through extensive research, we came to a similar conclusion as the Bielefeld 2013 iGEM team did; that this task was too comprehensive to undertake in the limited time of an iGEM project. Postdoc Oona Snoeyenbos-West suggested us to use G. sulfurreducens as the model organism for our MFC.
We then decided to work on optimisation of the G. sulfurreducens by increasing the electrical conductivity of its endogenous nanowires. To achieve this we ordered synthesis of the pilA genes from G. metallireducens, which was used to create a Biobrick. From this Biobrick, a PCR product was made containing the chloramphenicol resistance cassette of the pSB1C3 backbone for later selection of recombinant G. sulfurreducens. The PCR product was ligated with PCR products retrieved from the 500 bp upstream and downstream regions of the chromosomal pilA genes of the G. sulfurreducens PCA strain. This was used to create the following linear DNA fragment, intended for homologous recombination into G. sulfurreducens:


Demonstration and Results








Parts & Procedures

In this section, you will find all the needed information to replicate our approach and experiments. The constructed parts, notebook, SOPs and protocols will show in a pop-up window , from which you can obtain all the necessary knowledge, should you be interested. An essential part of going to the lab is risk and safety assessments, which you will find at the end of the section.

Parts

Notebook

SOPs and Protocols

Safety

Proper Risk Management

Biosafety and proper risk assessment are important aspects to consider before any handling of genetically modified organisms (GMOs). There are several concerns that must be addressed properly. The safety of the public as well as of the environment is of the utmost importance, but the safety of the person in direct contact with the GMOs should not be compromised either. The risk associated with laboratorial work can be evaluated using the statement “Risk = Hazard ✕ Probability”. To responsibly address this inquiry, the entire team was given a mandatory lab safety course held by Lab Technician Simon Rose. In addition, we received a detailed handbook regarding lab safety. This ensured that all our team members were well equipped to work safely in the lab. Throughout the project we have continuously been evaluating the safety of our work. These assessments can be found in the safety form. Furthermore, our team participated in the 5th annual BioBrick workshop hosted by DTU BioBuilders. Here we participated in a lab safety course before entering their laboratories. Both of these lab safety courses gave us the necessary knowledge to work safely with GMO and handle waste appropriate, as well as the according procedures in case of an emergency.
In the lab, we worked with several potentially harmful chemical agents such as dimethylsulfoxide (DMSO), ethidium bromide, chloroform, phenol, Congo red, antibiotics, and autoclaved glycerol. These chemical agents were handled using gloves at all times, and whenever deemed necessary, handled in a fume hood. Gloves were worn when necessary, and clean lab coats were worn restrictedly in the laboratorial areas. To visualise bands in agarose gels, we used an UV board. UV rays are carcinogenic when exposure is frequent and prolonged. To reduce the amount of exposure, several precautions were made. Gloves, long sleeves and a facial screen were worn at all times, and the time spend at the UV board was kept at a minimum.

Public and Environmental Risk Assessment

The chassis organisms containing the system is meant to be contained in a device, which is incorporated into an urban environment. While this device would be a safely enclosed container, it still possess the risk of physical breakage from violent acts or environmental disturbances. For this reason, we consulted a plastics expert, who advised us to use the plastic known as Polycarbonate. This plastic is remarkably durable, with the ability to ward off most physical traumas. The plastics expert has estimated that such a container would last in an urban environment for at least 20 years, and most likely more than that. To illustrate the durability of the plastics, he notified us of several devices from the 1980s made of the same plastic, which still stand strong today.
One of the biggest concerns would be the release of GMOs into nature. While the GMOs used are not pathogenetic, they would be able to share the plasmids containing antibiotic resistance selectors to other bacteria, that might be pathogenic. Antibiotic resistance in pathogenic bacteria complicates the treatment of an infected individual and could, in tragic cases, be the difference between life and death. However small the risk of this scenario might be, it should be addressed properly. Furthermore, antibiotic resistant E. Coli strains could outmatch some of their fellow E. Coli strains through natural selection. This could negatively affect the balance of nature, that we are aiming to restore with the development of the PowerLeaf.
To avoid these risks, several kill switch mechanisms should be implemented into the final device. This could be performed by implementation of a kill switch activated by exposure to light in the energy converting unit. This would of course mean, that the energy converting unit’s container would need to block all sunlight. A task that could easily be carried out by adding Carbon Black to the required areas of the container. The energy storing unit, which requires light to function, could then have a kill switch which makes it dependent on the presence of the energy converting unit. This could be accomplished by having harmless molecules, not naturally found in nature but required for the survival of the energy converting unit, circulating in the system. A similar effect could be accomplished by making the bacteria in the energy converting and storing units codependent on each other for their survival. The implementation of such kill switch mechanisms would tremendously improve the biosafety of the device by opposing hazards related to any kind of physical breakage.

List of Assessed Items


Chassis Organisms
Escherichia coli strains: K12, TOP10, MG1655, KG22, BW25113, DF25663127, SØ928
Geobacter Sulfurreducens strain: PCA
Vectors
pSB1A2: An iGEM plasmid backbone carrying a ampicillin resistance gene
pSB1A3: An iGEM plasmid backbone carrying an ampicillin resistance gene
pSB1C3: An iGEM plasmid backbone carrying a chloramphenicol resistance gene
pSB3C5: An iGEM plasmid backbone carrying a chloramphenicol resistance gene
pSB1K3: An iGEM plasmid backbone carrying a kanamycin resistance gene
pSB4K5: An iGEM plasmid backbone carrying a kanamycin resistance gene
pSB3K3: An iGEM plasmid backbone carrying a kanamycin resistance gene
Bacteriophages
P1 phage, using its site-specific recombinase for transduction of E. Coli

Practices

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Vestibulum tincidunt ac nisl at mattis. Sed eu mollis nisi. In pulvinar mi velit, dictum congue sapien ornare vel. Integer euismod varius velit ac euismod. Curabitur dapibus eget neque hendrerit sollicitudin. Etiam nec consequat diam, interdum egestas purus. Nullam ultricies et augue at vestibulum. Proin ac velit ac nibh rutrum varius at id metus. Morbi vitae auctor arcu, eget pulvinar mi. Suspendisse potenti. Fusce ornare nisi a volutpat malesuada. Donec sed augue nisl. Vivamus et dui orci. Suspendisse potenti. Ut luctus, nisl in ullamcorper facilisis, purus tortor eleifend odio, nec efficitur erat nisl vel massa. Suspendisse sed velit molestie, tincidunt nulla in, consectetur ligula.

Bioethics

ethics is forcing Neergaard drink phenol

Jonas can approve on this

Integrated Practices

“The best way to predict your future, is to create it”


Abraham Lincoln - (former) president of the United States of America


Not that we can claim to be anything like Abraham Lincoln, or even to be vampire hunters, but we do agree that to create the future we all hope for, we must contribute to finding a sustainable solution for a greener future. However, before we can tackle the arduous task of providing a sustainable future for the entire world, we must first look to our own local environment to better understand its vision for the future. Hopefully this approach will help future iGEM teams find a connection between global issues and local ones - as we believe that the best way to gain a better understanding of a global dilemma, is to examine how a local environment is affected by it, and how it could possibly be tackled in such a setting. This approach has helped us elucidate specific issues and to find sustainable solutions that can be implemented into our society with the help and endorsement of local agents.

integrate a pizza here

A Statement from the Mayor of Odense

We first decided to reach out to the mayor of Odense, to investigate the possibilities for iGEM to help in the government's endeavours to make Odense a CO2 neutral city, with a high quality of life.

“We face a series of challenges that we have to recognize, in the chase of a good and sustainable life in the city of Odense. Some of these concern local circumstances, while others contain national and even global issues. We as the municipality can only go so far on our own. So we are entirely dependehttps://2017.igem.org/Team:SDU-Denmark/testnt on the help of local agents. It makes me so happy, when the students of the city, have taken on the mantle of developing new green technologies, which global issues while also contributing to the city's high quality of life.”


Peter Rahbæk Juel - Mayor of Odense


The core philosophy of our integrated human practices has been to integrate local experts in the development of our project; in order to better comprehend how to use the knowledge gained in the laboratory to shape a product that would compliment Odenses (or beyond) green values. We have also made use of experts in other fields in order to better understand how to shape our project - and so our human practice has influenced everything from the design of our prototype(s), laboratory work to ethical considerations.
We will now walk you through our integrated human practices, so scroll on down to find out more about who we spoke with and how their input and advice came to influence our entire iGEM experience.

Meeting with Kristina Dienhart


For the purpose of a possible implementation of the PowerLeaf into the different areas of Odense city’s renewal, we decided to reach out to Kristina Dienhart. Kristina Dienhart was at this point in time project manager of Smart City Odense – a project within Odense Municipality that seeks to combine urban planning with new technologies and open-data, in order to create a smarter city. We decided to consult mrs. Dienhart, as Smart City Odense shares our core values; working transparently, openly and collaborative, while also sharing know-how. Mrs. Dienhart made us aware of the following necessities for Odense and its citizens - feedback that we have integrated in numerous areas of our overall project. It is important to note that at the time of our meeting with Mrs. Dienhart, our vision of the PowerLeaf was exclusively in the shape of a leaf; a leaf designed to be implemented on various buildings around Odense.

  • From Mrs. Dienhart’s point of view, one of the most advantageous attributes of our device, is the the potential for changeability in the size and shape of the PowerLeaf - as this means it could be shaped depending on what urban area we wish to integrate the PowerLeaf within. We had yet to consider the PowerLeaf as a device not limited by physical dimensions, and it’s perhaps the most significant element we took away from our meeting with Mrs. Dienhart. Changeability is a necessity to a city planner, as various laws and aesthetic aspects need to be taken into consideration, when altering or creating an urban environment.
  • Accessibility – the citizen will not use our device if it is not easily accessible. This means that the overall design of PowerLeaf – regardless of its aesthetic – always needs to be designed with a user in mind. Offering a mobile-charger in a city-space is only clever insofar that the citizen using the public space is aware of the device and how to easily access it. Reflecting on the advice of Mrs. Dienhart, we decided to reevaluate the means of implementation of our bacterial solar battery in the prototype, to ensure that the need for accessibility and user-comfort is met.
  • Mrs. Dienhart supported our notion that offering free and accessible energy within public space could help ensure that the ordinary citizen of Odense uses and stays in the public space for a longer amount of time. Something that is valuable not only to the individual citizen but also to the community as a whole, as it creates a sense of city-cohesion and hence a high quality of city-life.
  • Overall Mrs. Dienhart confirmed that our PowerLeaf could play a part in Odenses dream of developing into an even greener and more lively city. She also made us aware that not every neighbourhood in Odense will be desiring the same design, and that we ought to focus on the changeability aspect in the development of our prototype’s design.

Overall Mrs. Dienhart introduced us to several considerations that shaped large parts of our project. Her call for ‘the changeability aspect’ of the PowerLeaf has been used to reconsider the construction of the solar battery’s exterior and sustainability. We do not know the needs of every urban area in Odense; and consequently - with Mrs. Dienhart in mind – we have aimed to create a device that is changeable to a city in movement such as Odense. Mrs. Dienhart therefore challenged what we thought we wanted from a prototype - namely a fixed design - into the belief that we ought to create a prototype that can be shaped and reshaped depending on the requested necessities of the customer.
Furthermore the conversation with Mrs. Dienhart was also a source of inspiration in regards to our ethical and safety thoughts. The belief that while we ought to create a better more sustainable tomorrow for ourselves and future generations, we do not necessarily have to provide an exhaustive description of what that future should like, very much evolved from the changeability aspect, which was brought about by our conversation with Mrs. Dienhart.

Meeting with Rikke Falgreen Mortensen

Mrs. Dienhart also helped to establish contact with Rikke Falgreen Mortensen, manager of the Bolbro’s city-renewal project called MyBolbro. We arranged a meeting with Mrs. Mortensen with the intent of further investigating how the PowerLeaf could and should be integrated into an urban area of Odense - in this case the neighbourhood Bolbro.
Bolbro is an old neighbourhood in Odense historically known to be the home of the working-class, and while Bolbro provides a homely atmosphere known to the locals, it has had a hard time attracting new residents. However, this is subject to change as the neighbourhood in 2016 received a reservation of approximately 1,6 million us dollars to renew its city-space and create an even more appealing and vibrant neighbourhood. This will be achieved by including the locals, as Bolbro is characterized by having a strong, engaging civil society. Mrs. Mortensen is not only an expert in urban renewal but also in how to include local citizens in reshaping the public space in which they reside.
Mrs. Mortensen, as Mrs. Dienhart, also argued that a changeable design would be the optimal solution to fit the challenges, One faces in creating a vibrant, green city-ambience. As such a task depends on preferences, laws and needs. Instead a technology needs to be both flexible and accessible in order to successfully contribute to the process of creating a successful city environment. Furthermore we had a discussion with Mrs. Mortens about the creation of a prototype based on the wishes of Bolbro’s local citizens.

“Hauge’s square is a spot in Bolbro, which we aim to make a central place in Bolbro; a place that invites the citizen to meet and dwell. At the same time it must also be an orientations point, from where citizens and visitors can find their way to other places and attractions in Bolbro. Today the possibility for enjoying the outside consists of the space in Hauge’s square, which is made up by a bakery, a small local library, and a parking lot. However, we believe that the space contains better opportunities. In short, the space must be transformed from primarily being a parking spot to a recreational place with a much more aesthetic design. Your solution should be able to contribute to help citizens recharge their phones, ex. A solution could be implanting the PowerLeaf into a ‘living’ furniture, but where demands for the aesthetic design still remains”



“A part of the vision of this project is the concept of making a pop-up park with differently designed multi-furniture, preferably in wood and organic design, which are removable to the various areas where we are going to develop in the district. It is furniture that should be able to be used to relax in and at the same time also motivates children to move - and there should also be platforms that invite to activity ex. table tennis or a more screened seating for lovers, conversation or work. There is also a need for charging devices and it therefore demands that your solution is an integrated but still mobile solution, as the park will move physically over time”



“Finally, the church / playground is to be developed especially for the young audience, which is a major consumer of power for phones. The place must be a place where the youngsters hang out after school, still a green space where the solution should be integrated into the interior and could keep the target audience children and adolescents. The site is in a socially charged area, so it demands a robustness from of the solution, to help when faced with ex. vandalism”



The making of the furniture as a prototype called for a re-visit of our safety concerns, as children will be climbing and playing on the furniture, it is crucial that the material of the PowerLeaf will not break; a concern we discussed with Flemming Christiansen, which you will be able to read more about next. Just keep scrolling!

Flemming Christiansen

Criteria to the Prototype
Having decided that the exterior of the device would be made entirely from plastic, we set out to.
Plastic is thought of as an undesirable material, due to the difficulties in its disposal. This is due to plastic being of a xenobiotic nature, making it generally recalcitrant to microbial degradation. This predicament is complicated further by biodegradable plastics being of a compensatory nature; sacrificing form-stability and strength for biodegradability. Following these concepts, we can identify the following set of criteria for our material:


  • Solar exposure - The material covering the solar cell, must allow sunlight to pass through it to the bacteria.
  • UV resistance - As the material will be exposed to the sun, it should be resistant to the UV radiation.
  • Bacterial growth - The material must support, or not be toxic to the bacteria.
  • Easy to mold - As the device is only dependent on the insides, the outside could be molded depending on the co
  • Durability - material must be able to withstand hard conditions and heavy weight.
  • Temperature -The material must allow for appropriate temperature for the bacteria, despite the constant sun exposure.
  • Longevity - We would like for the material to have as long a durability as possible, as replacing the leaves often would prove cumbersome. In this regard we are aiming for at least twenty years.
  • Price - We are looking for a material that is as cheap as possible, without sacrificing the necessary criteria.
  • Environmentally friendly - Considering the goal of this project being the creation of an environmentally friendly energy source, the ideal material would be as environmentally friendly as possible.

Interview with Flemming Christiansen For the purpose of finding the necessary materials for our prototype, we contacted one of the leading plastic experts in Denmark, Flemming Christiansen, who acts as the market development manager of SP Moulding. He has been acting as a plastics consultant, since his graduation as a master of science in Engineering with a speciality in plastics in the 1970ies. A meeting was quickly arranged, where we fleshed out the criteria, the technical design, the material and the possible price of creating the PowerLeaf.
In accordance with our established criteria, mr. Christiansen suggested that we use the plastic known as Polycarbonate, specifically Lexon 103R-III (kilde). The material, however, cannot fulfill the criteria on it’s own. Therefore, Mr. Christiansen suggested that we take a few liberties with it. In order to prevent the exposed part of the prototype from degradation by UV radiation, we will be adding certain additives to the surface of the exposed part. This doesn’t hinder the sunlight from entering the device and thus the bacteria, but just increases the UV-resistance of the material. During our consultations with Mr. Christiansen, we reached the topic of what to do in case of a breach. Should the container against all expectations be damaged, the GMOs inside would be exposed to the environment. The solution we came up with was the possible implementation of a kill-switch in the energy storage unit, making it vulnerable to light. Should the bacteria of said unit be exposed to sunlight, they would die, and since it’s counterpart in the solar cell unit would be dependent on the continued coexistence of the two units, the entire GMO system would be purged. With Mr. Christiansen’s help we designed the container for Cell 2 of the same material as Cell 1, albeit with an added compound. The container for Cell 2 would be covered with Carbon Black, which has the ability to absorb sunlight, thus leaving the compartment itself in darkness.
The process of constructing our device would be through an extensive use of Injection Moulding, which is considered pricey equipment. Next, one must purchase the required material, which at above 1 ton would cost around 4-5.5 USD per kg. As such it’s an expensive material compared to others, but it’s longevity and durability means one would not be required to replace the devices for a long time. Lastly, we discussed the reusability of Polycarbonate, which Mr. Christiansen assured us was of no concern, as the material could be reused and recycled with ease.

Meeting with Ann Zahle Andersen


During our iGEM experience we met with Business Developer Ann Zahle Andersen twice. Mrs. Andersen had arranged two workshops for us based on a business canvas. This helped us to understand our project in a larger perspective. She encouraged us to view our project as if it was supposed to be a startup business, and through this perspective we gained a better comprehension of society’s pull and pushes on a project like ours. In a time of crisis she discussed our project’s advantages and disadvantages from a business perspective. A perspective and talk that forced us as a team to get to the bottom of what we found important about our project. And to truly appreciate the advice we have been given throughout our human practice work, as if we were a business trying to understand the needs of a costumer.

Upcoming Meeting with Borgernes Hus


‘Borgernes Hus’ is a new initiative offered by the city’s central library. The name translates to ‘House of the Citizen’s’. The house aims to offer guidance and advice to projects such as our own. It is meant to aid Odense in its journey towards the status of a modern, danish city. Unfortunately, the building remains under construction until after our trip to Boston, meaning that they have been busy finishing said construction while our project was underway. It is for this reason, that we along with director Jens Winther Bang Petersen decided that a future collaboration would be the most suitable solution.
It is our hope, that a collaboration with Borgernes Hus will be of assistance to future iGEM SDU-Denmark teams as well as students from Odense. In extension of this, we hope that such a collaboration will help them see the benefits in collaborating with local agents.

Education & Public Engagement

hello my friend, wanna learn something? the wiki isn't done yet.

lets goo

Prospects

Our prospects section is aimed to expand on the vision of the PowerLeaf, a vision we would love to see develop into reality. For this reason we have created an overview of the project, in the hope that it will benefit future iGEM teams. Additionally, it is aimed to assist prospective teams, should they wish to take the PowerLeaf to the next level.

Perspectives

Building a Product for a Better Future

The purpose of the PowerLeaf is to provide a greener alternative to the currently available sources of energy. An important aspect of such an undertaking, is to limit the use of depleting resources in the construction of the device itself. This is accomplished through the use of the most common resources available, recyclable plastics and bacteria. This in turn, will contribute to our dream of building a better future. A future where fear of reaching a critical shortage of natural resources has been eliminated. Another benefit of the PowerLeaf, is the bacteria's ability to self-replicate, if provided with the essential nutrients.
As tools for genomic editing improves, the advancement of biological devices will conceivably become even more complex and independant. They will do so by introducing new metabolic pathways inspired from other organisms using genetic engineering. This could potentially allow the PowerLeaf to become completely independent through its self-replication. An ability that would occur when the bacteria are engineered to produce their own essential nutrients directly from unwanted pollution in the environment. A trait that would lead to cleaner cities, along with providing a natural solution to sustainable energy.

Genetic Code Expansions for Biological Engineering

In an effort to advance technologies used in today’s synthetic biology, research groups are working on genetic code expansion. We had an interesting talk from postdoc Julius Fredens, about his work on genetic code expansion. Once a technology like this advances, it will completely revolutionise biological engineering, including that of the PowerLeaf. Genetic code expansion could be used for optimisation of the systems in the PowerLeaf, such as optimisation of nanowires, improvement of the light-sensing system and making the breakdown of cellulose inducible.

To Future iGEM Teams

Hello future iGEM’er and congratulations on starting your iGEM journey! You are going to have an amazing time with plenty of wonderful experiences, knowledge and new friendships. In this section some ideas for improvement and further development of our project, the PowerLeaf, will be presented.

Further Development of Our Project

For those of you that are interested in our project and would like to improve upon it, this is the section you have been looking for. We have listed the systems and the related information needed for the fulfillment of the device we envisioned. Nonetheless, you should not feel restricted by these suggestions. You are more than welcome to contact any of us regarding questions to the project. You can find each of our team members contact informations in the Team section in the Credits.
Systems that did work:

  • Light sensing system, this is used by the energy storing unit to reduce metabolism during times of the day with low amounts of solar energy available for the energy production, i.e. night time. We had several failed attempts during the development and optimization of the system and have through this learned a lot about the system. Furthermore, the system was modelled to gain an even greater understanding about the regulation of its light sensitivity. You can read about the work we did regarding the light sensing system here.

  • Cellulose consumption, this was used by the energy converting unit to degrade cellulose to glucose from which electrons could be retrieved. This system is probably the most straightforward, but was also worked on very extensively. You can read about the work we did regarding cellulases here.

  • Optimisation of the nanowires, this system was heavily inspired by the following article (link). We did create the required BioBricks to make the system work, but still requires some extensive work to actually implement it. You can read more about the work regarding the nanowires here.

Systems that didn’t work:

  • CO2 fixation, we retrieved the parts from the Bielefeld 2014 iGEM team and worked on assembling their parts into one fully functional BioBrick. However, we had a lot of trouble assembling it, and it seems that Bielefeld 2014 didn’t succeed on combining all the components needed for CO2 fixation either. So be aware of this. It seems like a simple assembly, but has caused us lots of problems. Some of the larger BioBricks tend to do that when they reach a certain size. You can give it a go anyways, but make sure to have a backup-plan, or maybe even try to redo the CO2 fixation by using a system from a different organism. We essentially decided to let go of this system of the PowerLeaf to focus on some of the other components. You can still read about our work done regarding the CO2 fixation here.

  • Cellulose production and secretion from the fixated CO2. These parts were retrieved from the Imperial College London 2014 iGEM team, this, much like the CO2 fixation, gave us trouble when it came to the assembly of the large BioBricks. It did seem that Imperial College London 2014 made their system work, but in the end, they proved it to be very inefficient of producing cellulose. So, this part could be the very thing to improve. You can still read about our work regarding the cellulose production and secretion here.

Systems we didn’t work on, but should be implemented in the device:

  • ATP production from solar energy comes to mind as one of the most essential system needed for the PowerLeaf to actually work. We had to pick the some of the systems to work on, and at the end of the day, this was the project our supervisors recommended to cut, if we wanted to work on more than just one system. Instead, we had a great Skype call early in the project with the Australian Macquarie iGEM team, whom has been working for many years with the implementation of the photosynthetic systems in E. coli. You could always contact them regarding the photosynthetic systems, they are super nice.

  • Making the interaction between the cellulose and the cellulases a controllable element, so it could be controlled in the same way of an on/off switch. This is also a very crucial part of the PowerLeaf, since it would otherwise be generating an electrical current non-stop. Even when it is not needed, and thereby overthrow the potential for long term-storage of solar energy. We believe this can be solved either through precise gene circuit regulation or by physical compartmentalization, however there might be even more elegant ways to solve this issue.

  • Physical engineering of the hardware required to make the device work. It should be possible for the energy storing unit to convert CO2 to cellulose, which will produce O2, thus making its chamber aerobic. For the energy converting unit to effectively transfer retrieved electrons to an anode, it will need to be in an anaerobic chamber. This will be a very difficult obstacle to overcome and requires some out-of-the-box thinking, to come up with a novel idea without having to require more energy than produced by the system. Engineering of the hardware required, e.g. anode, chamber, circulation of important nutrients and use of the correct plastic, is really important to make a workable prototype of the PowerLeaf. We worked out the optimal type of plastic for the system with the help of local experts. You can read about our work regarding the plastic here.

Ideas from Our Idea Generation


List of ideas from our idea generation

Credits

“You'll stay with me?” - “Until the very end”


J.K. Rowling, Harry Potter and the Deathly Hallows


Just like in the movies, you only get to meet the brilliant minds behind the project in the closing credits. Some might leave the cinema without sitting through the credits, but we hope you will sit through ours, as you will get to know us on a more personal level. We probably have more in common than you think. And do not forget that behind every great team is an equally great amount of external attributions. The contributors have supported and inspired us, especially when things have been rough and deadlines closeby. When you finish this section, we kindly ask that you turn your attention to our various collaborations, all of which have been amazing experiences. They truly show of that wonderful iGEM spirit!
Finally, we do not want you to miss out on the ‘after-the-credits-clip’ that summarises the fun we had during this fantastic iGEM adventure. This is will be the moment you will get that long-awaited ‘thank you for listening, we hope you enjoyed our wiki and project’.

Team

Welcome to the team page, here you get to know us on a more personal level. As a team, we are 12 students from 8 different majors. As friends, we experienced the most amazing summer together, filled with various fun activities, both in- and outside the lab. To mention a few; we had road trips, dinners, Game of Thrones night and we even celebrated Christmas in July! We shared all of this with our amazing supervisors, for which we are truly greatful.


Ellen Gammelmark


Study: Biochemistry and Molecular Biology
E-mail: elgam15@student.sdu.dk
Why, hello there! My name is Ellen, and I spend most of my waking hours either in the lab with a pipette in my hand, or just outside it with a computer on my lap. You know.. Learn iGEM, live iGEM, love iGEM!

Emil Bøgh Hansen


Study: Biology
E-mail: ehans15@student.sdu.dk
Howdy! I’m the first of many Emil’s, and the team's only biologist! I am a huge wolf enthusiast! This summer I put my boots in the closet, in order to put on a proper lab coat doing iGEM. Besides my time in the lab I’ve also looked into how GMOs can influence the environment.

Emil Søndergaard


Study: History
E-mail: emsoe09@student.sdu.dk
Ahoy thar! My name is Emil, and I want to be the next Indiana Jones. But before I can raid any tombs, I’ve decided to raid iGEM trophies. When I’m not cooking or travelling, I’m drawing on my background in history for communications and human practices.

Emil Vyff Jørgensen


Study: Physics
E-mail: ejoer15@student.sdu.dk
Mojn! I am yet another Emil! I might not be a model biochemist, so instead I am modelling biochemistry! My iGEM existence is a stochastic binary function between naps and extreme bursts of energy.

Felix Boel Pedersen


Study: Biochemistry and Molecular Biology
E-mail: feped15@student.sdu.dk
Aloha. My name is Felix and I bring joy to others by eating my daily ryebread with paté and wearing my magical red racer rain coat. Speaking of magic, I’m the team’s wiki lizard (get it?). I also do dry-lab and when the other miss me too much, I join them in the wet lab.

Frederik Bartholdy Flensmark Neergaard


Study: Biochemistry and Molecular Biology
E-mail: frnee15@student.sdu.dk
Hey yo! I’m Frederik and I have worked day and night on iGEM, mostly drinking beers at night time, but that should count as well. When I’m not working in lab or on the PC, I make fun with the other teammates and tell bad dad jokes. Also I make crazy ideas come true, like celebrating christmas in July.

Frederik Højsager


Study: Medicine
E-mail: frhoe14@student.sdu.dk
Heyah! I’m the other Frederik. I’m a green, lean, coffee-machine. I’ve been the steady supplier, and consumer of coffee on the team. My main focus has been on how to build a sustainable iGEM-project. I’ve been planting trees, eating green and lowering our team's carbon-footprint. Oh, and did I also mention I starred in our commercial? You can get autographs later.

Jonas Borregaard Eriksen


Study: Pharmacy
E-mail: jerik15@student.sdu.dk
Hey sup? I’m Jonas and used to like sports, partying, eating cake, hanging out with friends and such things most people like to do. During iGEM these interest has changed… I have been enslaved into the lab, and has realised that the only purpose of my life is to be in the lab.

Lene Vest Munk Thomsen


Study: Philosophy
E-mail: letho11@student.sdu.dk
Hey, is it solipsistic in here, or is it just me? When not wondering whether or not there is an external world, I’ve been busy working out how to implement our solar battery into our local community and what to gain from doing so. Oh, and imposing metaethics on my team members, but I Kant go into detail with this just yet.

Malte Skovsager Andersen


Study: Biochemistry and Molecular Biology
E-mail: malta14@student.sdu.dk
Ey what up pimps, I’m Malte. I’ve mostly been working in the lab wrapped in the dankest of lab coats, doing the most exciting of experiments. All in the name of why the hell not. In the lab the utmost highest level of patience is needed, especially when tasked with testing if biobricks function as intended. This has, as seen in the image, caused me to pull out most of my hair.

Sarah Hyllekvist Jørgensen


Study: Biochemistry and Molecular Biology
E-mail: sajo415@student.sdu.dk
Despite my favorite occupation being going into depth with theory, my main attribution to our project has primarily been running around in the lab. Luckily, there is a clear link between wet- and dry-lab. I am the smallest member of the SDU iGEM team, but I have definitely risen to the occasion.

Sofie Mozart Mortensen


Study: Biomedicine
E-mail: sofmo15@student.sdu.dk
Hi there! My name is Sofie, and I am the team mama! I am the one who makes sure everyone gets their fair share of cake. When I’m not in the kitchen, busy making cakes for my teammates, you can find me in the lab, where I’m working on enhancing our systems cellulose production.

Project Synergism


We have all been working together in every aspect of our project. Nevertheless, some people have had to focus on some areas more than others. The main groups are listed as follows;

  • The group focusing on fixation of CO2, production of cellulose and light-sensing dormancy consisted of Sarah Hyllekvist Jørgensen, Ellen Gammelmark, Sofie Mozart Mortensen and Emil Bøgh Hansen.
  • The group focusing on the breakdown of cellulose to create an electrical current and optimisation of nanowires consisted of Felix Boel Pedersen, Frederik Bartholdy Flensmark Neergaard, Jonas Borregaard Eriksen and Malte Skovsager Andersen.
  • The group focusing on the implementation of the device in an urban environment, as well as our outreach consisted of Emil Søndergaard, Frederik Mark Højsager and Lene Vest Munk Thomsen.
  • The mathematical modelling of our project was single-handedly performed by Emil Vyff Jørgensen.
  • Coding and design of the wiki was performed by Felix Boel Pedersen and Frederik Mark Højsager.

Collaboration

"Alone we can do so little; together we can do so much"


The American author Helen Keller had it right! As an iGEM team, you can reach many goals, but as an entire community, we can aspire to achieve so much more. We would like to thank all the people that made this iGEM experience so memorable, we truly enjoyed your companionship!

Danish Ethics and Wiki Workshop at SDU

In the spirit of the iGEM community, we hosted a meetup in August for our fellow Danish iGEM teams: InCell from the University of Copenhagen (KU), and the Snakebite Detectives from the Technical University of Denmark (DTU). A total of seven members from these two teams joined us for breakfast and attended our meetup. This was the first ever iGEM meetup hosted by our university, so we decided to make it memorable. We took advantage of our interdisciplinary team roster, and thus designed a wiki and ethics workshop to aid our fellow Danish teams.
We utilised the broad interdisciplinary profile of our team, to have Emil S. and Lene present the perception of science throughout the history and the meta-bioethical aspects of GMO, respectively. Emil S. has a Bachelor of Arts in History, and Lene has a Bachelor of Arts in Philosophy. The ethical presentation was purposely turned into an ethical debate, where viewpoints of ethical conduct were exchanged and discussed. After the presentations and discussions on metaethics, it was time for the wiki workshop.
The SDU-Denmark iGEM teams have won the Best Wiki prize several times in the past. As such, we wanted to share the knowledge gained from our university's experience. To facilitate this exchange of knowledge on wiki development, we recruited our current supervisor Thøger Jensen Krogh, to facilitate presentations on how to design a good wiki page. He was qualified for this task through his role as the designer of the SDU iGEM 2013 and 2014 team wikis, which won the special prize on both occasions. During the presentation, Thøger had arranged several exercises where the attendees got to mingle, discuss and evaluate their wikis. This resulted in a steady flow of information and constructive feedback between all three teams.
After a long day of learning and discussing, we went for a tour around campus under the summer sun, which concluded in a visit to the roof terrace of the campus dormitory, followed by dinner. It was requested, by our fellow Danish teams, to make the SDU meetup a tradition.

Attending Meetups

Besides hosting our own meetup, we also attended several ones during our iGEM experience. The first of which, was the 5th Annual Biobrick Workshop in March, hosted by the Technical University of Denmark, DTU-Denmark. This meetup not only gave us our first experience with Biobricks, but also worked as a foundation for friendships across the teams.
Our second meetup, the Nordic iGEM Conference, was hosted by the University of Copenhagen, UCopenhagen, in June. The main focus of this meetup, was the traditional mini Jamboree. Participating in this gave us useful feedback from the judges, as well from our fellow iGEM teams. This helped us greatly shape and develop our project for the better.
To celebrate the beginning of our iGEM summer, we went on a road trip to attend the European Meetup, hosted by the Delft University of Technology in the Netherlands. Here we discussed ideas regarding our project at a poster session, learned from all the other great iGEM projects, and made new friends from all over Europe.

Further Collaboration

In our project, we have been in contact with the iGEM teams from Bielefeld and Imperial College, who helped us by sending crucial parts relevant to the execution of our project.
As our project revolves around global warming and green sustainable energy, we were thrilled to hear about the iGEM Goes Green initiative from the TU Dresden iGEM team. Following their guidelines, we have calculated the carbon footprint of our laboratory work and travelling. We have, in part, tried to make up for our carbon footprint, by changing our travelling and eating habits in our everyday lives. Furthermore, we have reduced our daily electricity consumption, our wiki became CO2 neutral and we made an effort to sort our waste. The full report can be scrutinized here **link to report*. Due to our team being the most green team TU-Dresden asked us to run the iGEM Goes Green project in 2018.
We sought expertise from the Macquarie Australia iGEM team, who has worked with the implementation of photosynthesis in E. coli since 2013. We had an interesting Skype call with their team, where we discussed the particular challenges the previous teams had experienced throughout their projects.
We were also able to help the Stony Brook iGEM team by facilitating communication with members of the SDU iGEM team from 2016.
During our project we received several questionnaires from fellow iGEM teams. We were delighted to help the teams by answering their questionnaires. The questionnaires were from:

  • Waterloo - regarding 3D printing of lab equipment
  • Dalhousie - regarding the common conception of science literature
  • University of Washington - regarding communication platforms used by teams
  • Vilnius-Lithuania - regarding cotransformation
  • Nanjing-China - regarding whole-cell sensor for formaldehyde
  • University of Sydney - regarding the use and accessibility of insulin
  • Georgia State - regarding disabilities
  • Greece - regarding modular RNAi-based logic circuits

Attributions

Nothing can be done alone, so please scroll further to read about the contributors, who helped make this project a reality.

Laboratory, Technical and General support


We would like to give a special thanks to our supervisors:

  • Assistant professor Mikkel Girke Jørgensen, for his general support and advice on the project, the laboratory, the fundraising and our team synergy.
  • Ph.D. student and former iGEM participant Patrick Rosendahl Andreassen, for his guidance and technical assistance in the laboratory.
  • Ph.D student and former iGEM participant Thøger Jensen Krogh, for his help in developing the wiki, as well as his laboratory guidance.
  • Cand.phil student and former iGEM participant Tim Munk, for his focus on team dynamics and advice for our human practices.

We would also like to thank:

  • Academic assistant Tina Kronborg, for her guidance in the lab, as well as for providing us with laboratory equipment.
  • Medical Laboratory Technician Simon Rose, for giving us a course in lab safety, risk assessment and general guidance in the lab.
  • Postdoc Oona Sneoyenbos-West, for providing us with Geobacter Sulfurreducens PCA and the necessary knowledge on how to grow this particular bacterial strain. Furthermore, she helped us greatly with helpful discussions regarding the advancement of our project. We would also like to thank her for lending us her laboratory, for the cultivation of Geobacter Sulfurreducens PCA.
  • Postdoc Satoshi Kawaichi, for his assistance in measuring the electrical conductivity of our nanowires, as well as providing us with knowledge on the Geobacter Sulfurreducens.
  • Business scout and PhD Ann Zahle Andersen, for presenting us with the necessary tools for the development of innovative business ideas.
  • Stud.scient Kristian Severin Rasmussen, for helping us use the oCelleScope for testing.
  • Stud.scient Brian Baltzar, for hosting a workshop regarding Adobe Illustrator, which has been a great help to the development of graphics for our wiki.
  • Ph.D student Richard Xavier Etienne Valli, for helpful discussions in the lab.
  • Software Developer Jonas Hartwig, for his help with some JQuery functionality on the wiki.
  • Stud.scient Birka Jensen, for general advice and suggestion on how to build an iGEM wiki.
  • Stud.med Ida Charlotte Hvam, for helpful discussions on the development of our wiki, helping with last minute figures to the wiki, as well as proof-reading of its content.
  • Ph.D student and current iGEM advisor of the team from Bielefeld, Boas Pucker, for providing us with BioBricks created by former iGEM teams from Bielefeld.
  • Our iGEM HQ Representative, Traci Haddock-Angelli, for her general guidance and assistance in registering our meetup to the official iGEM meetup page.
  • iGEM HQ Representative and Lab Technician, Abigail Sison, for her help in registering our meetup to the official iGEM meetup page.
  • Stud.polyt Oliver Klinggaard, for helpful discussions on the implementation of a pan-tilt system and for providing os with his project report on the subject.
  • DTU BioBuilders, for hosting their 5th Annual Biobrick Workshop. And for attending our meetup.
  • The UNIK Copenhagen iGEM team, for hosting the Nordic Meetup. And for attending our meetup.
  • The TU-Delft iGEM team, for hosting the European Meetup.
  • Mimo Antabi, for adding our adverts to the university info-screens preceding the Danish Research Festival.
  • Anders Boe, for putting an enormous amount of work into the post-production of our commercial.
  • Allan Haurballe Madsen, for helping us with our appearance at the Danish Science Festival.
  • Outreach Coordinator and PhD Lise Junker Nielsen, for for helping us with the Danish Science Festival as well as with the visit from the Academy for Talented Youth. We would also like to thank her for providing us with iPads for laboratory use.
  • The Danish Science Festival, for having us at their annual event. We would also like to thank all the visitors who attended our booth.
  • The high schools Odense Technical gymnasium, Mulernes Legatskole and Academy for Talented Youth, for letting us present our project.
  • The UNF Biotech Camp, for having us present our project to the attending students.
  • The elementary school, Odense Friskole, for letting us present our project for their 8th grade students.
  • All former iGEM participants from SDU, for attending our preliminary presentation and giving us feedback before the Giant Jamboree.
  • The following groups and associations, for helping us develop our human practices: SP-Moulding, Borgernes Hus, Kommunens bygninger, Bolbro - områdefornyelse, Odense Byudvikling.
  • Project manager (Smart City Odense) Kristina Dienhart, for wonderful advice on how to involve Odense Municipality in our project, as well for having a long conversation with us about the city’s current projects and how our solar battery could be implemented. We would also like to thank her for providing us with contact informations and for leading us to Bolbro city renewal.
  • Project Manager Bolbro City Renewal (DitBolbro) Rikke Falgreen Mortensen, for meeting with us to discuss how The PowerLeaf could be implemented in the city neighbourhood of Bolbro’s urban renewal.We would also like to thank her for providing us with a pitch, more contact informations and reading materials on Odense’s green goals.
  • Director of audience - and central library Odense (Borgernes Hus)Jens Winther Bang Petersen, for an email correspondence and hopefully a future meeting with members of our iGEM team.
  • Matlab user Nezar, for an easy implementation of the gillespie algorithm into matlab.

Sponsors


Thanks to:

  • The Faculty of Science at University Southern Denmark, for providing us with the fundamental funds required for our participation in the iGEM competition, and for providing us with laboratory benches and essential equipment.
  • The Faculty of Health Sciences at University of Southern Denmark, for their much needed funding of our project.
  • Integrated DNA Technologies, for providing us with 20 kilobases of gBlock gene fragments.
  • SnapGene, for providing our team with memberships to their software during the duration of the competition.
  • PentaBase, for sponsoring us with 10.000 DKK worth of oligos and a further 10% discount.
  • New England Biolabs, for providing our team with a BioBrick® Assembly Kit, a Q5® High-Fidelity 2X Master Mix and a Quick-Load® Purple 2-Log DNA Ladder.
  • CO2NeutralWebsite, for attributing to green energy in our name, and thereby eliminating the carbon footprint our wiki makes.
  • Piktochart, for extending their student-offer to our mail aswell, providing us with easy access to great graphics.

Litterature


Final Words

Thank you for your time! We hope you enjoyed our wiki and getting to know our project.
Now you can sit back, relax, and be proud of your hard work. While you do so, feel free to enjoy some of the less serious pictures and snippets from our amazing iGEM adventure.
Take a look at these telling pictures from our iGEM experience.