Thursday 18 August; Leiden, Lital Alfonta "Site specific wiring of redox enzymes in biofuel cells"



van Marum Colloquium

Location: room L144 Gorlaeus, LION, Leiden

time: 13:15 hrs

Speaker:  Professor Lital Alfonta
Affiliation:  Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben-Gurion University of the Negev

Electrical communication between microorganisms and electrodes, when designing a biofuel cell, is one of the most crucial issues to take into consideration. Once shuttling of electrons to and from electrodes is prevented due to the absence of proper “wiring”, such a fuel-cell cannot function, thus energy cannot be harnessed. Various mechanisms are suggested for the electron transfer to occur, but they are poorly understood. One of our major research interests is to study the electron transfer mechanisms between bacteria and other microorganisms with electrodes and to attempt to artificially improve it.

Microbial fuel cells are fuel cells which make use of microorganisms as the catalysts in room temperature operating fuel cells. Enzyme based fuel cells make use of purified enzymes as catalysts in similarly operating systems. Recently, we have created a hybrid cell (enzyme-microbial fuel cell) by displaying on the surface of S. cerevisiae a redox active enzyme (Glucose oxidase) and assessed the power output of a microbial fuel cell based on these yeast cells in comparison with S. cerevisiae not displaying these redox enzymes on their surface. The surface display system and the yeast displaying redox enzymes have proved to be very efficient and have contributed to a significant improvement in power outputs in such devices. We have expanded our approach for the display of an array of other redox as well as non redox active enzymes and we are currently attempting to electrically wire these displayed enzymes to electrodes. These examples will be presented and discussed.

In summary while improving using our approach power outputs in bio-fuel cells we are also attempting to understand what makes electrochemically active microorganisms, electrochemically active?

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