Hydrogen evolution catalyzed by viable and non-viable cells on biocathodes
KAUST Grant NumberKUS-I1-003-13
Permanent link to this recordhttp://hdl.handle.net/10754/672257
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AbstractThe presence of microorganisms on cathodes has been shown to enhance the hydrogen evolution reaction (HER), but a requirement for viable cells has not been sufficiently examined. HER was examined using live or killed biocathodes of exoelectrogenic (Geobacter sulfurreducens) and non-exoelectrogenic (Escherichia coli) bacteria, and a hydrogenotrophic methanogen (Methanosarcina barkeri). Electrodes at a set potential of -0.6 V (versus a standard hydrogen electrode) containing G. sulfurreducens biofilms or killed controls produced hydrogen at a similar rates (118 ± 15 nmold-1 mL-1) over 5 months. Electrodes containing cell extracts produced hydrogen at approximately half this rate (56 ± 6 nmold-1 mL-1). Biocathodes fed lactate produced only 14 ± 2 nmol/d-mL. Electrodes inoculated with M. barkeri produced hydrogen at a rate (120 ± 18 nmold-1 mL-1) similar to the G. sulfurreducens, but no methane was recovered after the initial inoculation cycle. Non-exoelectrogenic E. coli cells and extracts produced hydrogen at a slower rate (13 ± 1 and 4 ± 1 nmold-1 mL-1, over 3 cycles). Electrodes exposed to viable cells that were examined after 5 months had increased levels of in nitrogen, sulfur, iron, nickel, cobalt, and peptides (possibly remnants of hydrogenases and other oxidoreductases) relative to uninoculated controls, and no intact cells. These results show that enhanced HER can result from cell debris and that living cells are not required.
CitationYates, M. D., Siegert, M., & Logan, B. E. (2014). Hydrogen evolution catalyzed by viable and non-viable cells on biocathodes. International Journal of Hydrogen Energy, 39(30), 16841–16851. doi:10.1016/j.ijhydene.2014.08.015
SponsorsThe authors would like to thank Dr. James Ferry for providing the M. acetivorans culture. We also thank John Cantolina and Tatiana Laremore in the Penn State Huck Institutes of the Life Sciences for assistance with SEM imaging and protein analysis, and Vince Bojan in the Materials Research Institute for assistance with XPS. This research was supported by Award KUS-I1-003-13 from the King Abdullah University of Science and Technology (KAUST) and by Award DGE-1255832 to M.D.Y. by the National Science Foundation (NSF) Graduate Student Fellowship Program. M. S. was supported by the Global Climate and Energy Program (GCEP).