Extracellular Electron Transport: Mechanism(s) and Applications

THE MORK FAMILY DEPARTMENT OF CHEMICAL ENGINEERING AND MATERIALS SCIENCEPRESENTS A SEMINAR
BYKen Nealson
Wrigley Professor of Environmental Sciences Department of Earth Sciences and Biological Sciences University of Southern CaliforniaonExtracellular Electron Transport: Mechanism(s) and Applicationsabstract Microbes constitute more than half the biomass on our planet ­ their immense success is, in large part, due to their ability to catalyze reactions at rates orders of magnitude higher than they would occur in the absence of life, using protein catalysts called enzymes. In particular, microbes are experts at electron transfer, seemingly being able to transfer an electron to any substrate that will accept one. Recently, it was discovered that microbes have the capacity to donate electrons to solid substrates (e.g., solid metal oxides or metal-rich clays), leading to rapid catalysis of these substrates via direct electron transport. One such organism, Shewanella oneidensis is seemingly the master of this type of metabolism, being capable of reduction of more than 15 different substrates, including iron and manganese oxides, metal rich clays, and even the anodes of fuel cells. The nature of the electron transfer process, while still being elucidated, shows hints of being something different from anything
previously observed. Under conditions of electron acceptor limitation, S.
oneidensis makes copious amounts of extracellular enzymes, as well as long extracellular structures (nanowires) that are highly conductive, and necessary for the reduction of solid metal oxides, and the production of current in microbial fuel cells. Results of recent studies of the nanowires and their properties will be discussed.

Location: John Stauffer Science Lecture Hall (SLH) - 102

Audiences: Everyone Is Invited

Contact: Petra Pearce