Environmental Science and Engineering Seminar

The iron-reducing bacteria Geobacter and Shewanella, as well as acetogenic, methanogenic, and iron-oxidizing bacteria have all been shown to perform extracellular electron transfer (EET) when grown as biofilms on the surface of electrodes. However, our understanding of the microbial electrical wiring that enables this non-natural connection is remarkably limited. Understanding electrode EET processes could result in leap-ahead technological advancements in applications including microbial electrosynthesis, bioremediation, and microbial bioelectronics. In this talk I will describe our work over the past 7 years using meta-omics and microbial electrochemistry to search for better electroautotrophs, bacteria presumed to "eat" electricity and use the energy gained to fix CO₂. First, I will present metaproteomic and metatranscriptomic data supporting our discovery of a previously uncharacterized electroautotroph from a marine biocathode microbial community (Biocathode-MCL), which we have recently proposed as the candidate genus and species "Candidatus Tenderia electrophaga". Second, I will describe electrochemical measurements using an interdigitated electrode array and complimented by confocal Raman microscopy (CRM) indicating that long-range electron transfer (conductivity) through this biocathode biofilm is dominated by electron-hopping, presumably mediated by "Cd. T. electrophaga". I will conclude by briefly outlining approaches our group is taking to genetically modify "Cd. T. electrophaga" to exploit its potential for electrosynthesis.