Multiple paths of electron flow to current in microbial electrolysis cells fed with low and high concentrations of propionate
Type
ArticleKAUST Department
Biological and Environmental Sciences and Engineering (BESE) DivisionChemical and Biological Engineering Program
Environmental Science and Engineering Program
Water Desalination and Reuse Research Center (WDRC)
KAUST Grant Number
FCC/1/1971-05-01GRP-CF-2011-15-S
Date
2016-03-03Online Publication Date
2016-03-03Print Publication Date
2016-07Permanent link to this record
http://hdl.handle.net/10754/621478
Metadata
Show full item recordAbstract
Microbial electrolysis cells (MECs) provide a viable approach for bioenergy generation from fermentable substrates such as propionate. However, the paths of electron flow during propionate oxidation in the anode of MECs are unknown. Here, the paths of electron flow involved in propionate oxidation in the anode of two-chambered MECs were examined at low (4.5 mM) and high (36 mM) propionate concentrations. Electron mass balances and microbial community analysis revealed that multiple paths of electron flow (via acetate/H2 or acetate/formate) to current could occur simultaneously during propionate oxidation regardless of the concentration tested. Current (57–96 %) was the largest electron sink and methane (0–2.3 %) production was relatively unimportant at both concentrations based on electron balances. At a low propionate concentration, reactors supplemented with 2-bromoethanesulfonate had slightly higher coulombic efficiencies than reactors lacking this methanogenesis inhibitor. However, an opposite trend was observed at high propionate concentration, where reactors supplemented with 2-bromoethanesulfonate had a lower coulombic efficiency and there was a greater percentage of electron loss (23.5 %) to undefined sinks compared to reactors without 2-bromoethanesulfonate (11.2 %). Propionate removal efficiencies were 98 % (low propionate concentration) and 78 % (high propionate concentration). Analysis of 16S rRNA gene pyrosequencing revealed the dominance of sequences most similar to Geobacter sulfurreducens PCA and G. sulfurreducens subsp. ethanolicus. Collectively, these results provide new insights on the paths of electron flow during propionate oxidation in the anode of MECs fed with low and high propionate concentrations.Citation
Hari AR, Katuri KP, Gorron E, Logan BE, Saikaly PE (2016) Multiple paths of electron flow to current in microbial electrolysis cells fed with low and high concentrations of propionate. Applied Microbiology and Biotechnology 100: 5999–6011. Available: http://dx.doi.org/10.1007/s00253-016-7402-2.Sponsors
This work was sponsored by a Ph.D. fellowship, a Global Research Partnership-Collaborative Fellows Award (GRP-CF-2011-15-S), and Center Competitive Funding (FCC/1/1971-05-01) to P.E.S. from King Abdullah University of Science and Technology (KAUST). Special thanks are extended to Bioscience Core Laboratory at KAUST for 454 pyrosequencing.Publisher
Springer NaturePubMed ID
26936773ae974a485f413a2113503eed53cd6c53
10.1007/s00253-016-7402-2
Scopus Count
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