title: Impact of volatile fatty acids on microbial electrolysis cell performance.
abstract: This study investigated the performance of microbial electrolysis cells (MECs) fed with three common fermentation products: acetate, butyrate, and propionate. Each substrate was fed to the reactor for three consecutive-batch cycles. The results showed high current densities for acetate, but low current densities for butyrate and propionate (maximum values were 6.0 ± 0.28, 2.5 ± 0.06, 1.6 ± 0.14 A/m(2), respectively). Acetate also showed a higher coulombic efficiency of 87 ± 5.7% compared to 72 ± 2.0 and 51 ± 6.4% for butyrate and propionate, respectively. This paper also revealed that acetate could be easily oxidized by anode respiring bacteria in MEC, while butyrate and propionate could not be oxidized to the same degree. The utilization rate of the substrates in MEC followed the order: acetate > butyrate > propionate. The ratio of suspended biomass to attached biomass was approximately 1:4 for all the three substrates.
authors.affiliation: Department of Civil and Environmental Engineering, University of Western Ontario, London, Ontario N6A 5B9, Canada.
authors.forename: Nan
authors.initials: N
authors.lastname: Yang
authors.affiliation: Department of Civil and Environmental Engineering, University of Western Ontario, London, Ontario N6A 5B9, Canada; GreenField Ethanol Inc., Chatham, Ontario N7M 5J4, Canada.
authors.forename: Hisham
authors.initials: H
authors.lastname: Hafez
authors.affiliation: Department of Civil and Environmental Engineering, University of Western Ontario, London, Ontario N6A 5B9, Canada; Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario N6A 5B9, Canada. Electronic address: gnakhla@eng.uwo.ca.
authors.forename: George
authors.initials: G
authors.lastname: Nakhla
mesh_terms: D001674:Bioelectric Energy Sources / Q000382:microbiology*; D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D004560:Electricity; D004566:Electrodes; D004572:Electrolysis / Q000379:methods*; D005232:Fatty Acids, Volatile / Q000494:pharmacology*; D006859:Hydrogen / Q000378:metabolism; D007475:Ion Exchange Resins / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D005232:Fatty Acids, Volatile; D007475:Ion Exchange Resins; D006859:Hydrogen
keywords: Biomass; Hydrogen; Microbial electrolysis cell; Volatile fatty acids