Everything is Connected!

Prologue

On November 2015, Indonesia massively highlighted as the second worst plastic polluters to the sea. It inspires us to develop a project benefiting the environment and Indonesia image. We came up with a project named Dewaruci. It should be inspiring and sustainable. For that, we involve various stakeholder into our project design, execution, and future outlook. Here is how everything is connected.

Bioreactor Concept Design

Dr. Sri Harjati Suhardi gave us an insight of the future application of our project. She suggests us to build a safety containment to prove the safety of GMO as the first step to convince the society. Therefore, we made a bioreactor concept as the first stage of future application. We hope this concept could be enhanced and realized in the near future.

The bioreactor is operated on batch mode with a hundred liters of capacity. To fulfill the oxygen requirement, air is supplied at the rate of 2 vvm continuously to the vessel. The medium consists of 1.5 kg of molasses as a minimum carbon source. As the nitrogen source, we use 0.5 kg of fish waste as minimum amount. A hundred milliliter of kanamicyn is added to prevent the invasion of foreign microbes. Sea water is added until reach working volume 100 L. The diagram is given below:

There are two operation stage:

1. Inoculation Stage

In this stage, the bacteria is grown until reaches quorum sensing phase, which triggered at 1 × 107 times of the initial cell concentration. According to growth kinetics model, the time needed to reach the quorum sensing is 10 hours, using the assumption in which the specific growth rate of bacteria is half its maximum value.

2. Degradation Stage

Sea water is pumped into vessel and the bacteria will degrade the plastic debris as well as micro-plastic. The mixing rate should be reduced in order to minimize the drag force when bacteria starts forming a biofilm on PET surface.

According to ethylene terephthalate production model, we can calculate degraded PET by stoichiometric reaction approach:

Hence, we got 0.84 mg of PET that degraded. Reaction yields can calculate by equations :

We obtain that the yield of the degradation is 49.93%(w/w), which indicates that this process is affordable to be upscaled into the commercial scale.

Productivity can also calculate based on data that we have. Productivity calculated by equation :

The productivity of the reaction is 0.00209 g(L-1 h-1). From this data, we determine the degradation capacity which is the multiplication of productivity to bioreactor capacity on a yearly basis. The production capacity 1.83 kg/year for a 100L bioreactor. Aside from technical analysis, we also do the economic assessment. The bioreactor is not purposed to be a profitable tool, rather a remediation tool. Hence, we only calculate the capital investment and operational cost. The capital cost of the bioreactor system is listed as below:

To operate a single bioreactor would need a medium that cost:

We assume the bioreactor would operate on a weekly basis. Hence, the operational cost would be fitted for 52 weeks or 52 batch. The total medium cost would be 818 USD/year. Electricity cost was calculated by using national tariff which is Rp 1467/kWh or 0.11 USD/kWh. Overall, the total cost to operate a 100L bioreactor is 2467 USD/year.

Indonesia iGEM Booklet Vol. 1

Lastly, we put all the affordable knowledge into one documented media, Indonesia iGEM Booklet Vol. 1. Public engagement program gave us an overview about people awareness on synthetic biology. We are trying to increase the awareness by writing a booklet. The booklet was written in Bahasa to prevent a language barrier in the learning process. It is consist of the synthetic biology basic knowledge and our projects. The basic knowledge includes the definition of synthetic biology, part, device, and system. We also elaborate the previous, recent and future outlook of our iGEM projects. We put the past four years of ITB team human practice, dry lab, and wet lab in detail. It was our contribution to inspire another Indonesian team. The booklet then distributed to academician through an email. We hope this effort could generate more innovative solution through synbio field in Indonesia.

Conclusion

Overall, the stakeholders have given us a lot reasoning of our project. It is how the world affects ours. Dr. Ivonne's suggest how the idea should be executed. Her suggestion has given the reason behind the module selection. Dr. Sri Harjati suggests an insight into the future application. Hence, we develop a bioreactor concept aimed at the sustainability of Dewaruci project. The fishermen interview open our eyes that the problem does exist. Moreover, our visit on Sarimukti Landfill has surprisingly revealed another plastic issue. Again, the problem is bigger than the solution. Our project should now affect the world. We are trying to generate the solution by making a well-documented and creative media to inspire the world. Start small for a greater good.