Team:Aachen/Results

Results

Functional Microbial Supercollector: VAULTer I

Our goal was to maximize sodium accumulation in S. cerevisiae. With our measurements we successfully proved that our design leads to higher sequestration of sodium. A yeast mutant taking up 5x more NaCl than the native wildtype, sequestrating 39% (6g/L) of the NaCl of a media containing 0.6 M NaCl (equal to seawater salinization).

Concept: Microbial Supercollector

Many different pollutive ions threaten the earth environment. Means there are varying demands for purifying ions, e.g. wastewaters. To tackle this issue, we developed a concept of microbial supercollectors adaptable to more than just Na+. To proof the adaptability, we additionally designed and tested a mutant capable of sequestrating potassium.

Halotolerant Yeast

During the project, we noticed a significant higher halotolerance of some mutants than the wildtype. This fundamental insight can be utilized for many other applications as well as for our applied design.

Application

We developed a fundamental design for an application in wastewater treatment, including nutrition, separation and after-use of yeast. Regarding the process, but also in terms of safety and responsibility, it is crucial to separate yeast and water. We validated ultrafiltration as a convenient method for that, so we avoid environmental harm through the spreading into the environment of the sequestrated ions.

Raising awareness

Through many talks and educational work, we initiated a debate on genetic engineering in Germany.

Modelling

Modelling of the ion pathways in modified yeast. To predict the thermodynamic feasibility of the ion sequestration in the yeast vacuole and to model time needed to accumulate the ion in the vacuole.

Assembled and submitted a tested and functional BioBrick

We created a Biobrick of the Na+/H+ antiporter AtNHXS1 which occurs in the membrane of vacuoles and is one of the most important transporters in our project. The sodium uptake of S.cerevisiae containing the AtNHXS1-gen is doubled, the chloride-uptake is three times as high. Furthermore, the biobrick of AtSultr1;2, a high-affinity sulfate transporter, represents the expansion of our project from NaCl to the additional accumulation of other salts. – Both biobricks are sequenced.

Development of a functional and affordable peristaltic dosing system

And what went wrong?

• We underestimated the effort to genetically modify yeast, therefore we could not implement and test all combinations of modifications which we planned at the beginning.
• The measurement of the chloride content failed for a few mutants due to the difficult detection of chloride in YPD.
• We indented to develop several BioBricks but didn’t accomplish all of them due to time limitation.
• We could not realize every idea due to the lack of cooperation with some corporate partners.