title: Microbial community composition and dynamics in high-temperature biogas reactors using industrial bioethanol waste as substrate.
abstract: Stillage, which is generated during bioethanol production, constitutes a promising substrate for biogas production within the scope of an integrated biorefinery concept. In this study, a microbial community was grown on thin stillage as mono-substrate in a continuous stirred tank reactor (CSTR) at a constant temperature of 55 °C, at an organic loading rate of 1.5 goTS/L*d and a retention time of 25 days. Using an amplicon-based dataset of 17,400 high-quality sequences of 16S rRNA gene fragments (V2-V3 regions), predominance of Bacteria assigned to the families Thermotogaceae and Elusimicrobiaceae was detected. Dominant members of methane-producing Euryarchaeota within the CSTR belonged to obligate acetoclastic Methanosaetaceae and hydrogenotrophic Methanobacteriaceae. In order to investigate population dynamics during reactor acidification, the organic loading rate was increased abruptly, which resulted in an elevated concentration of volatile fatty acids. Acidification led to a decrease in relative abundance of Bacteria accompanied with stable numbers of Archaea. Nevertheless, the abundance of Methanosaetaceae increased while that of Methanobacteriales decreased successively. These findings demonstrate that a profound intervention to the biogas process may result in persistent community changes and reveals uncommon bacterial families as process-relevant microorganisms.
authors.affiliation: Institute of Technical Microbiology, Hamburg University of Technology, Kasernenstraße 12, Hamburg, 21073, Germany.
authors.forename: Immo
authors.initials: I
authors.lastname: Röske
authors.forename: Wael
authors.initials: W
authors.lastname: Sabra
authors.forename: Heiko
authors.initials: H
authors.lastname: Nacke
authors.forename: Rolf
authors.initials: R
authors.lastname: Daniel
authors.forename: An-Ping
authors.initials: AP
authors.lastname: Zeng
authors.forename: Garabed
authors.initials: G
authors.lastname: Antranikian
authors.forename: Kerstin
authors.initials: K
authors.lastname: Sahm
mesh_terms: D001105:Archaea / Q000145:classification* / Q000235:genetics; D001419:Bacteria / Q000145:classification* / Q000235:genetics; D056804:Biofuels; D019149:Bioreactors / Q000382:microbiology*; D058448:Biota; D003470:Culture Media / Q000737:chemistry; D019641:DNA, Archaeal / Q000737:chemistry / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D000431:Ethanol / Q000378:metabolism*; D005227:Fatty Acids / Q000032:analysis; D005285:Fermentation; D008969:Molecular Sequence Data; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013696:Temperature
chemical_list: D056804:Biofuels; D003470:Culture Media; D019641:DNA, Archaeal; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D000431:Ethanol