Creation of an optimized biologically battery powered by genetically engineered cyanobacteria
The transition from fossil fuel-based to sustainable energy production plays a central role in the ongoing fight against climate change. To provide sustainable and economically viable energy supply, innovative and radical concepts from chemistry and biology are urgently needed. Recently, the application of cyanobacteria in biological batteries has been proposed as a promising energy source. As photoautotrophs, cyanobacteria thrive on water and sunlight to transform CO2 into organic compounds. Placed in a biological battery, electrons gained from water oxidation, are transferred out of the cell to an electrode, consequently producing a photocurrent. However, present prototypes based on wild-type cyanobacteria generate low current output and are considered insufficient energy suppliers. Presumably this is due to inefficient electron transfer to the extracellular space. Therefore, this project aimed at optimizing a cyanobacterial battery, by expressing the porin-cytochrome complex mtrCAB from the facultative anaerobe Shewanella oneidensis in Synechocystis. Since mtrCAB enables S. oneidensis to efficiently transfer electrons to electrodes, we hypothesized that mtrCAB-expressing Synechocystis should outperform the wild-type strain in terms of current output.