Team:Aachen/Applied Design

iGEM Team Aachen 2017

Applied Design


The outcome of an environmental project, like the Salt Vault, depends on thoughts on its feasibility and application. If no thought is given to application or use, the picture is not complete, just like a puzzle. Within our project we developed a design for the possible implementation of desalinating yeast into wastewater treatment and discussed its necessity in comparison to conventional desalination methods. Follow the flowchart to gather information on the applied design of a new way to handle wastewater – the Salt Vault.

Reverse Osmosis

Reverse Osmosis is an established technology to remove salt from water by retaining solvent molecules on a semipermeable membrane. This method is used in a variety of applications in saltwater desalination plants of countries struggling with freshwater supply. Reverse osmosis purifies water completely from all kinds of pollutants and molecules. However, it has got significant disadvantages, making it necessary to think about alternative solutions.

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Salt taken up from solution

Salt Uptake

The most promising Salt Vault we created is capable of taking up X times more NaCl than the native wildtype. This Salt Vault with a dry mass of X g/L sequestrates X % NaCl of a media containing 0.6 M NaCl (35,1g per Liter), which is equal to the average salt content of sea water. A dry mass of X g/L is roughly equal to the concentrations of bacteria in industrial wastewater treatment plants. Being specific for certain ions, the Salt Vault purifies the water only from wished solvents, in this case NaCl, making it more efficient than reverse osmosis. With the vision of a microbial supercollector, a huge range of specific pollutants could be removed from differing wastewaters.

Salt Vault and Membrane Technology

The use of a genetically modified organism raises the question how to separate the yeast from water. The answer is membrane technology - the much more energy- and maintenance-efficient micro- or ultrafiltration, which guarantees complete separation of the yeast from the purified water.

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Nutrition and After-Usage

Nutrition and after-usage of the yeast remain as unsettled questions for an application in wastewater treatment. Yeast is not able to grow directly in salinized water, making separate breeding necessary. Growth of the yeast depends on the availability of an external C-source, a cheap by-product of many industrial processes. A meaningful nutrition of the yeast must be set-up for specific industrial applications. After separation of the water, yeast, filled with ions, drop behind. We utilize the nutritional value of yeast and add it to fouling towers for enhanced gas production. Final burning of the cells would leave behind dry salt, which must be re-used or stored permanently.

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