Engineering bacteria to harvest electrons

Carbon dioxide can be converted into organic molecules by photosynthesis, which requires a source of electrons. Some bacteria, such as Rhodopseudomonas palustris TIE-1, can harvest these electrons from environmental Fe2+ using special outer membrane transporters that trap the electrons inside the cell. By replacing the Fe2+ with an electrode it could be possible to build microbial electrochemical systems that use electrical power to power bacterial metabolism.
This project aims to understand how the transporters in R. palustris TIE-1 manage to keep electrons inside the cell. Initially genetic engineering and site directed mutagenesis will be used to generate a hybrid electron transporter in the outer membrane of the model organism Shewanella oneidensis and the ability for electrons to move across the membrane investigated using a range of spectroscopic techniques. With the help of collaborators at the University of Minnesota a parallel set of hybrid strains will be assembled in R. palustris TIE-1 and also characterised to determine the ability of these strains to fix CO2. Finally the opportunity to measure formation of chemical products succinate and formate by hybrid S. oneidensis strains using electrons supplied by electrodes will be measured.