title: Metagenomic analysis and performance of a mesophilic anaerobic reactor treating food waste at various load rates.
abstract: The performance of a demonstration-scale anaerobic reactor treating food waste was evaluated with an emphasis on microbial response to increasing organic loading rates (OLRs). The reactor exhibited a stable performance in terms of methane yield at OLR ranging from 1.0 to 2.4 kg VS L-1day-1(phases I and II), compared to that at phase III (OLR: 1.0-1.5 kg VS L-1day-1) when the food waste exhibited greater acidity. Deep sequencing analysis revealed shifts in the microbial composition at each operational phase. The phyla Firmicutes and Bacteroidetes were favoured, whereas the abundance of Proteobacteria and Chloroflexi decreased at higher OLRs, indicating that fermenting-, hydrolytic- (and acidogenic) bacteria were selected under this condition. Changes were observed in the composition of methanogens, and not the abundance, in response to a shift in OLR. Methanosaeta and Methanospirillum dominated at low OLRs, indicating the importance of both acetoclastic and hydrogenotrophic methanogens for methane production during this condition. Methanosaeta almost disappeared at high OLRs, whereas Methanoculleus was favoured. Syntrophic prokaryotes were in high abundance (>9%), indicating that syntrophic methane production was important in this reactor. Syntrophic interactions between hydrogen-producer (Syntrophomonas and Desulfosporosinus) and hydrogenotrophic methanogens were more evident at high OLR. These results indicate that hydrogenotrophic methanogenesis contributed significantly to methane production at higher OLRs than when the reactor was operated at low OLR.
authors: a Departamento de Engenharia Sanitária e Ambiental , Universidade Federal de Minas Gerais , Belo Horizonte , Brazil.
authors: Alessandra
authors: http://orcid.org/0000-0002-1692-9514
authors: A
authors: da Silva Martins
authors: a Departamento de Engenharia Sanitária e Ambiental , Universidade Federal de Minas Gerais , Belo Horizonte , Brazil.
authors: Bernardo
authors: http://orcid.org/0000-0001-8703-573X
authors: B
authors: Ornelas Ferreira
authors: a Departamento de Engenharia Sanitária e Ambiental , Universidade Federal de Minas Gerais , Belo Horizonte , Brazil.
authors: Nirvana Cecília
authors: NC
authors: Ribeiro
authors: a Departamento de Engenharia Sanitária e Ambiental , Universidade Federal de Minas Gerais , Belo Horizonte , Brazil.
authors: Raiane
authors: R
authors: Martins
authors: b Genomics and Computational Biology Group , René Rachou Research Center, Oswaldo Cruz Foundation , Belo Horizonte , Brazil.
authors: Laura
authors: http://orcid.org/0000-0002-9542-9904
authors: L
authors: Rabelo Leite
authors: b Genomics and Computational Biology Group , René Rachou Research Center, Oswaldo Cruz Foundation , Belo Horizonte , Brazil.
authors: Guilherme
authors: http://orcid.org/0000-0003-0054-3438
authors: G
authors: Oliveira
authors: a Departamento de Engenharia Sanitária e Ambiental , Universidade Federal de Minas Gerais , Belo Horizonte , Brazil.
authors: Luis Felipe
authors: http://orcid.org/0000-0003-2589-3602
authors: LF
authors: Colturato
authors: a Departamento de Engenharia Sanitária e Ambiental , Universidade Federal de Minas Gerais , Belo Horizonte , Brazil.
authors: Carlos Augusto
authors: http://orcid.org/0000-0001-7226-8266
authors: CA
authors: Chernicharo
authors: a Departamento de Engenharia Sanitária e Ambiental , Universidade Federal de Minas Gerais , Belo Horizonte , Brazil.
authors: Juliana Calabria
authors: JC
authors: de Araujo
mesh_terms: D000693:Anaerobiosis; D001421:Bacteria, Anaerobic; D019149:Bioreactors; D056186:Metagenomics; D008697:Methane
chemical_list: D008697:Methane
keywords: Anaerobic digestion; Illumina sequencing; food waste; methane production; microbial community