Apr 2022
Host: The WDRC Students Committee
Abstract:
Electrochemically
active biofilms (EABs) can exchange electrons with an inert, conductive
surface - an electrode. Specifically, biofilms that deliver electrons
to the electrode are described as anodic biofilms, whereas biofilms that
accept electrons or facilitate reduction reactions at the electrode
surface are cathodic biofilms. The chemical and electrochemical
gradients in EABs play a critical role in electron transfer processes.
Most of the time, electron transfer processes have been investigated in
the bulk phase for a biofilm electrode or an isolated component of a
biofilm. Currently, the knowledge of chemical and electrochemical
gradients in EABs is limited. Chemical and electrochemical gradients are
critical for explaining electron transfer mechanisms. The bulk
conditions, an isolated part of EABs or a single cell, cannot be used to
describe electron transfer mechanisms in EABs. In addition, gradients
in EABs explain how the reactor configuration plays a critical role in
electron transfer processes. This presentation discusses how to grow the
EABs and the crucial choices made in the experimental setup that affect
the experimental results. We describe reactor configurations and
demonstrate how to use electrochemical and microscale techniques to
study extracellular electron transfer in biofilms. Finally, we address
some critical concerns with the proposed electron transfer mechanisms in
biofilms and the prospects of bioelectrochemical systems as
energy-converting and energy-harvesting devices.
Bio:
Haluk Beyenal
is widely known for his biofilm engineering expertise in the area of
microscale biofilm characterization and electron transfer processes in
biofilms. The research in his laboratories has focused on the
fundamental understanding of biofilm processes, their characterization,
and applications. He has developed many research tools for understanding
biofilm processes at the microscale, including microelectrodes for
monitoring local chemistry and electron transfer mechanism inside
biofilms. He has developed mathematical models for
predicting biofilm activity, electron transfer rates, and biofilm
structure. He pioneered the studies of electron transfer processes in
biofilms using microelectrodes and powering electronic devices using
microbial fuel cells. He and his collaborators in PNNL developed an
electrochemical nuclear magnetic resonance microimaging technique to
study electron transfer processes in biofilms. The microscale techniques
developed in his laboratory are critically used to study biofilms
respiring on electrodes. His research group also developed technology to
power remote sensors using energy harvested from microbial fuel cells.
His research has been supported by the Office of Naval Research,
National Science Foundation program, Department of Energy, Department of
Defense, National Institute of Health as well as industry. He and
Zbigniew Lewandowski published a book entitled "Fundamentals of Biofilm
Research" in 2007 and 2nd edition in 2013 and he received an
NSF-CAREER award in 2010. He and Jerome Babauta edited a book entitled
"Electrochemically active biofilms in microbial fuel cells and
bioelectrochemical systems: From laboratory practice to data
interpretation" in 2015. Currently, he is a Professor at Washington
State University, in the Gene and Linda Voiland School of Chemical
Engineering and Bioengineering.