Wiring Strategies of Microorganisms

Lital Alfonta, Life Sciences, Ben-Gurion University of the Negev, Beer-Sheba, Israel


Microbial fuel cells are devices in which microorganisms serve as catalysts for fuel oxidation in the anode and/or for oxygen reduction in the cathode, hence enable the flow of electrons in an external electrical circuit. These bacteria were termed as exoelectrogens or electricigens, however, many aspects of the mechanism of action are still not well understood. In our work we have set out to engineer bacteria and yeast such that different redox enzymes will be surface displayed and subsequently wired to electrodes, such that the electron transfer (ET) pathway will be well defined. In my presentation I will demonstrate the characterization of our genetically modified living systems that are designed to deliver electrons to and from electrodes, hence behave as true electricigens. We have explored both site-specific wiring as well as non-specific wiring of these genetically modified microorganisms to electrodes and studied their electrochemical behavior as a result of these changes. I will describe our approach for the display of enzymes suitable for anode compartment and for cathode compartment of a biofuel cell. I will also describe our efforts towards the site-specific wiring of these modified bacteria and the performance of these cells as well as our different approaches for non-specific wiring of these microorganisms.