NICOP - Study for synergetic electron transfer from dual species biofilm in anaerobic conductive sediment
Abstract
Project Summary/Abstract:Sediment microbial fuel cells (SMFCs) are currently being developed to provide persistent power for undersea devices for more than two years without any operation once it buried. While SMFCs generate low power levels (a few hundred milliwatts) compared to other renewable energy sources such as wind or solar, the energy production of SMFCs is sufficiently large to support low power sensors and intermittent communications. The sustainability and power output of SMFCs highly exceeds those of typical wastewater microbial fuel cells (MFCs) systems. However, it has been unclear what makes SMFCs better than MFCs, because both systems have similar community often dominated by iron-reducing (IRB) and sulfate-reducing bacteria (SRB). One unique feature of SMFCs is that neighboring SMFCs gradually influence each other for power output once the microbial community was matured in laboratory sediment systems. These observations may suggest that the microbial communities of the SMFCs dominated by IRB and SRB change their environment in such a way that enhances electrical interaction among SMFCs, and the biosynthesized conductive matrix contribute to the higher stability and current production of SMFC than MFC.To this end, we recently have found a synergetic effect of IRB and SRB for current production in half-cell anodic chamber. When we inoculated the two kinds of microbes on electrode surface in anodic chamber in the presence of lactate as a sole electron donor, highly conductive FeS minerals were generated and current production from microbe showed 100-fold higher value than single culture of either IRB or SRB. Because IRB and SRB supposedly compete each other for acquiring electron donor agents in natural environments, the presence of biosynthesized FeS may alter the interspecies interaction between IRB and SRB for synergetic current production. In this project, we, therefore, explore the mechanism of synergetic current production we observed using our in vivo electrochemical techniques, combining with microscopic techniques to monitor the single cell activity of SRB or IRB. This study will be the collaboration with Dr. Bart Chadwick / Dr. Lewis Hsu (SPAWAR SC Pacific) currently supported on other SMFC efforts through ONR (Dr. Linda Chrisey). Results generated from this research will aid in design and optimization of current and future SMFC systems. If successful, this research would also provide a new perspective for viewing the SMFC as a system and lead to further avenues of research in geobiology and environmental interactions in the marine environment.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 03, 2017
- Source ID
- N629091712038
Entities
People
- Akihiro Okamoto
Organizations
- Office of Naval Research
- United States Navy