Engineering bacteria to harvest electrons


Carbon fixation is an important biological process that removes the green house gas carbon dioxide from the atmosphere.  The best-known mechanism for doing this is photosynthesis, which requires a source of electrons. These electrons can be harvested from reduced iron in the environment and by replacing the iron with an electrode it could be possible to build microbial electrochemical systems that power bacterial metabolism and carbon fixation.

Recently we solved the structure of a protein ‘nanowire’ that allows the flow of electrons across the outer membrane.  The structure allows us to build models of the homologous nanowires that occur in photosynthetic iron oxidising bacteria and use these models to understand how they may differ in their ability to trap electrons inside the cell.

This project aims to understand the key difference between nanowire from photosynthetic and non-photosynthetic organisms with a view to optimising photosynthetic electron transfer.  Initially molecular biology techniques such as site directed mutagenesis will be used to change key residues in the nanowire structure.  Spectroscopy, electrochemistry and proteoliposomes will then be used to determine how these changes affect the nanowire.

This PhD will be supervised by Dr Tom Clarke in collaboration with Prof. Julea Butt. Depending on the direction of the project the student may collaborate with reseachers at the University of Minnesota to characterise alternative nanowires from other bacteria.

Informal enquiries can be made to Dr Tom Clarke (