title: Evaluation of hydrolysis and fermentation rates in microbial fuel cells.
abstract: This study determined the influence of substrate degradation on power generation in microbial fuel cells (MFCs) and microbial community selection on the anode. Air cathode MFCs were fed synthetic medium containing different substrates (acetate, glucose and starch) using primary clarifier sewage as source of electroactive bacteria. The complexity of the substrate affected the MFC performance both for power generation and COD removal. Power output decreased with an increase in substrate complexity from 99±2 mWm(-2) for acetate to 4±2 mWm(-2) for starch. The organic matter removal and coulombic efficiency (CE) of MFCs with acetate and glucose (82% of COD removal and 26% CE) were greater than MFCs using starch (60% of COD removal and 19% of CE). The combined hydrolysis-fermentation rate obtained (0.0024 h(-1)) was considerably lower than the fermentation rate (0.018 h(-1)), indicating that hydrolysis of complex compounds limits current output over fermentation. Statistical analysis of microbial community fingerprints, developed on the anode, showed that microbial communities were enriched according to the type of substrate used. Microbial communities producing high power outputs (fed acetate) clustered separately from bacterial communities producing low power outputs (fed complex compounds).
authors.affiliation: School of Chemical Engineering and Advanced Materials, Merz Court, Newcastle University, Newcastle upon Tyne NE1 7RU, UK. sharon.velasquez-orta@ncl.ac.uk
authors.forename: Sharon B
authors.initials: SB
authors.lastname: Velasquez-Orta
authors.forename: Eileen
authors.initials: E
authors.lastname: Yu
authors.forename: Krishna P
authors.initials: KP
authors.lastname: Katuri
authors.forename: Ian M
authors.initials: IM
authors.lastname: Head
authors.forename: Tom P
authors.initials: TP
authors.lastname: Curtis
authors.forename: Keith
authors.initials: K
authors.lastname: Scott
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology; D003470:Culture Media; D004566:Electrodes; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D006868:Hydrolysis; D012722:Sewage / Q000382:microbiology; D013213:Starch / Q000378:metabolism
chemical_list: D003470:Culture Media; D012722:Sewage; D013213:Starch; D005947:Glucose