title: Bacterial communities in thermophilic H2-producing reactors investigated using 16S rRNA 454 pyrosequencing.
abstract: In this study, the composition and diversity of the bacterial community in thermophilic H2-producing reactors fed with glucose were investigated using pyrosequencing. The H2-producing experiments in batch were conducted using 0.5 and 2.0 g l(-1) glucose at 550 °C. Under the two conditions, the H2 production and yield were 1.3 and 1.6 mol H2 mol glucose(-1), respectively. Acetic, butyric, iso-butyric, lactic and propionic acids were detected in the two reactors. The increase in substrate concentration favored a high H2 yield. In this reactor, a predominance of acetic and iso-butyric acids, 27.7% and 40%, were measured, respectively. By means of pyrosequencing, a total of 323 and 247 operational taxonomic units were obtained, with a predominance of the phylum Firmicutes (68.73-67.61%) for reactors with 0.5 and 2.0 g l(-1) glucose, respectively. Approximately 40.55% and 62.34% of sequences were affiliated with Thermoanaerobacterium and Thermohydrogenium, microorganisms that produce H2 under thermophilic conditions.
authors: University of São Paulo, Brazil. Electronic address: regianeratti@gmail.com.
authors: Regiane Priscila
authors: RP
authors: Ratti
authors: University of São Paulo, Brazil.
authors: Tiago Palladino
authors: TP
authors: Delforno
authors: University of São Paulo, Brazil.
authors: Dagoberto Yukio
authors: DY
authors: Okada
authors: University of São Paulo, Brazil. Electronic address: varesche@sc.usp.br.
authors: Maria Bernadete Amâncio
authors: MB
authors: Varesche
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D044822:Biodiversity; D019149:Bioreactors / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics*; D059014:High-Throughput Nucleotide Sequencing; D006859:Hydrogen / Q000378:metabolism*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D006859:Hydrogen
keywords: Fermentation; Firmicutes; Heat-shock; Thermoanaerobacterium; Thermohydrogenium