title: Different substrates and starter inocula govern microbial community structures in biogas reactors.
abstract: The influence of different starter inocula on the microbial communities in biogas batch reactors fed with fresh maize and maize silage as substrates was investigated. Molecular biological analysis by Denaturing Gradient Gel Electrophoresis (DGGE) of 16S rRNA gene fragments showed that each inoculum bore specific microbial communities with varying predominant phylotypes. Both, bacterial and archaeal DGGE profiles displayed three distinct communities that developed depending on the type of inoculum. Although maize and silage are similar substrates, different communities dominated the lactate-rich silage compared to lactate-free fresh maize. Cluster analysis of DGGE gels showed the communities of the same substrates to be stable with their respective inoculum. Bacteria-specific DGGE analysis revealed a rich diversity with Firmicutes being predominant. The other abundant phylotypes were Bacteroidetes and Synergistetes. Archaea-specific DGGE analysis displayed less diverse community structures, identifying members of the Methanosarcinales as the dominant methanogens present in all the three biogas digesters. In general, the source of inoculum played a significant role in shaping microbial communities. Adaptability of the inoculum to the substrates fed also influenced community compositions which further impacted the rates of biogas production.
authors.affiliation: a Institute for Chemistry and Biology of the Marine Environment (ICBM) , University of Oldenburg , Oldenburg , Germany.|b Emder Institut für Umwelttechnik (EUTEC) , University of Applied Sciences , Emden , Germany.
authors.forename: Preseela
authors.initials: P
authors.lastname: Satpathy
authors.affiliation: b Emder Institut für Umwelttechnik (EUTEC) , University of Applied Sciences , Emden , Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Steinigeweg
authors.affiliation: a Institute for Chemistry and Biology of the Marine Environment (ICBM) , University of Oldenburg , Oldenburg , Germany.
authors.forename: Heribert
authors.initials: H
authors.lastname: Cypionka
authors.affiliation: a Institute for Chemistry and Biology of the Marine Environment (ICBM) , University of Oldenburg , Oldenburg , Germany.
authors.forename: Bert
authors.initials: B
authors.lastname: Engelen
mesh_terms: D000693:Anaerobiosis; D001105:Archaea / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D056804:Biofuels / Q000032:analysis / Q000382:microbiology*; D019149:Bioreactors / Q000382:microbiology*; D019344:Lactic Acid / Q000378:metabolism; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000302:isolation & purification
chemical_list: D056804:Biofuels; D012336:RNA, Ribosomal, 16S; D019344:Lactic Acid
keywords: Anaerobic digestion; DGGE; biogas digesters; microbial population dynamics; phylogenetic analysis