title: Correlation between microbial community and granule conductivity in anaerobic bioreactors for brewery wastewater treatment.
abstract: Prior investigation of an upflow anaerobic sludge blanket (UASB) reactor treating brewery wastes suggested that direct interspecies electron transfer (DIET) significantly contributed to interspecies electron transfer to methanogens. To investigate DIET in granules further, the electrical conductivity and bacterial community composition of granules in fourteen samples from four different UASB reactors treating brewery wastes were investigated. All of the UASB granules were electrically conductive whereas control granules from ANAMMOX (ANaerobic AMMonium OXidation) reactors and microbial granules from an aerobic bioreactor designed for phosphate removal were not. There was a moderate correlation (r=0.67) between the abundance of Geobacter species in the UASB granules and granule conductivity, suggesting that Geobacter contributed to granule conductivity. These results, coupled with previous studies, which have demonstrated that Geobacter species can donate electrons to methanogens that are typically predominant in anaerobic digesters, suggest that DIET may be a widespread phenomenon in UASB reactors treating brewery wastes.
authors.affiliation: Department of Microbiology, University of Massachusetts Amherst, 01003 MA, USA; Energy Biosciences Institute, University of California, Berkeley, CA, USA. Electronic address: pravin@berkeley.edu.
authors.forename: Pravin Malla
authors.initials: PM
authors.lastname: Shrestha
authors.affiliation: Department of Microbiology, University of Massachusetts Amherst, 01003 MA, USA.
authors.forename: Nikhil S
authors.initials: NS
authors.lastname: Malvankar
authors.affiliation: Chemistry Department, SUNY Cortland, Cortland, NY 13045, USA.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Werner
authors.affiliation: Department of Microbiology, University of Massachusetts Amherst, 01003 MA, USA.
authors.forename: Ashley E
authors.initials: AE
authors.lastname: Franks
authors.affiliation: Department of Microbiology, University of Massachusetts Amherst, 01003 MA, USA.
authors.forename: Amelia
authors.initials: A
authors.lastname: Elena-Rotaru
authors.affiliation: Department of Microbiology, University of Massachusetts Amherst, 01003 MA, USA.
authors.forename: Minita
authors.initials: M
authors.lastname: Shrestha
authors.affiliation: Department of Microbiology, University of Massachusetts Amherst, 01003 MA, USA; Key Laboratory of Coastal Biology and Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong, China.
authors.forename: Fanghua
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Microbiology, University of Massachusetts Amherst, 01003 MA, USA.
authors.forename: Kelly P
authors.initials: KP
authors.lastname: Nevin
authors.affiliation: Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Largus T
authors.initials: LT
authors.lastname: Angenent
authors.affiliation: Department of Microbiology, University of Massachusetts Amherst, 01003 MA, USA.
authors.forename: Derek R
authors.initials: DR
authors.lastname: Lovley
mesh_terms: D000434:Alcoholic Beverages; D000693:Anaerobiosis; D001419:Bacteria / Q000145:classification / Q000254:growth & development*; D019149:Bioreactors / Q000382:microbiology*; D004553:Electric Conductivity; D000431:Ethanol / Q000032:analysis; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000382:microbiology*; D018508:Water Purification / Q000379:methods*
chemical_list: D000431:Ethanol; D012722:Sewage; D062065:Wastewater
keywords: Conductive pili; Direct interspecies electron transfer; Granules; Syntrophy; UASB reactor