title: Anaerobic digester bioaugmentation influences quasi steady state performance and microbial community.
abstract: Nine anaerobic digesters, each seeded with biomass from a different source, were operated identically and their quasi steady state function was compared. Subsequently, digesters were bioaugmented with a methanogenic culture previously shown to increase specific methanogenic activity. Before bioaugmentation, different seed biomass resulted in different quasi steady state function, with digesters clustering into three groups distinguished by methane (CH4) production. Digesters with similar functional performance contained similar archaeal communities based on clustering of Illumina sequence data of the V4V5 region of the 16S rRNA gene. High CH4production correlated with neutral pH and high Methanosarcina abundance, whereas low CH4production correlated to low pH as well as high Methanobacterium and DHVEG 6 family abundance. After bioaugmentation, CH4production from the high CH4producing digesters transiently increased by 11 ± 3% relative to non-bioaugmented controls (p < 0.05, n = 3), whereas no functional changes were observed for medium and low CH4producing digesters that all had pH higher than 6.7. The CH4production increase after bioaugmentation was correlated to increased relative abundance of Methanosaeta and Methaospirillum originating from the bioaugment culture. In conclusion, different anaerobic digester seed biomass can result in different quasi steady state CH4production, SCOD removal, pH and effluent VFA concentration in the timeframe studied. The bioaugmentation employed can result in a period of increased methane production. Future research should address extending the period of increased CH4production by employing pH and VFA control concomitant with bioaugmentation, developing improved bioaugments, or employing a membrane bioreactor to retain the bioaugment.
authors: Department of Civil, Construction and Environmental Engineering, Marquette University, P.O. Box 1881, Milwaukee, WI 53233, USA. Electronic address: kaushik.venkiteshwaran@marquette.edu.
authors: K
authors: K
authors: Venkiteshwaran
authors: INRA, UR0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, Narbonne F-11100, France.
authors: K
authors: K
authors: Milferstedt
authors: INRA, UR0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, Narbonne F-11100, France.
authors: J
authors: J
authors: Hamelin
authors: Department of Civil, Construction and Environmental Engineering, Marquette University, P.O. Box 1881, Milwaukee, WI 53233, USA.
authors: D H
authors: DH
authors: Zitomer
mesh_terms: D000693:Anaerobiosis; D001105:Archaea / Q000235:genetics*; D019149:Bioreactors; D008697:Methane; D012336:RNA, Ribosomal, 16S / Q000235:genetics*
chemical_list: D012336:RNA, Ribosomal, 16S; D008697:Methane
keywords: Digester efficiency; Methanobacterium; Methanosaeta; Methanosarcina; Methanospririllum; Next generation sequencing