title: Organic loading rate and food-to-microorganism ratio shape prokaryotic diversity in a demo-scale up-flow anaerobic sludge blanket reactor treating domestic wastewater.
abstract: We investigated the microbial community in an up-flow anaerobic sludge blanket (UASB) reactor treating domestic wastewater (DW) during two different periods of organic loading rate (OLR) and food-to-microorganism (F/M) ratio. 16S rDNA clone libraries were generated, and quantitative real-time PCR (qPCR) analyses were performed. Fluctuations in the OLR and F/M ratio affected the abundance and the composition of the UASB prokaryotic community, mainly at the species level, as well as the performance of the UASB reactor. The qPCR analysis suggested that there was a decrease in the bacterial cell number during the rainy season, when the OLR and F/M ratio were lower. However, the bacterial diversity was higher during this time, suggesting that the community degraded more diversified substrates. The diversity and the abundance of the archaeal community were higher when the F/M ratio was lower. Shifts in the methanogenic community composition might have influenced the route of methane production, with methane produced by acetotrophic methanogens (dry season), and by hydrogenotrophic, methylotrophic and acetotrophic methanogens (rainy season). This study revealed higher levels of bacterial diversity, metabolic specialization and chemical oxygen demand removal efficiency of the DW UASB reactor during the rainy season.
authors.affiliation: Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil.
authors.forename: Juliana
authors.initials: J
authors.lastname: Cardinali-Rezende
authors.forename: Juliana C
authors.initials: JC
authors.lastname: Araújo
authors.forename: Paulo G S
authors.initials: PG
authors.lastname: Almeida
authors.forename: Carlos A L
authors.initials: CA
authors.lastname: Chernicharo
authors.forename: José L
authors.initials: JL
authors.lastname: Sanz
authors.forename: Edmar
authors.initials: E
authors.lastname: Chartone-Souza
authors.forename: Andréa M A
authors.initials: AM
authors.lastname: Nascimento
mesh_terms: D001105:Archaea / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D019149:Bioreactors / Q000382:microbiology*; D058448:Biota; D005502:Food; D008697:Methane / Q000378:metabolism; D008969:Molecular Sequence Data; D009930:Organic Chemicals / Q000032:analysis*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012621:Seasons; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*; D062065:Wastewater / Q000382:microbiology*; D014894:Weights and Measures
chemical_list: D008697:Methane; D009930:Organic Chemicals; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D062065:Wastewater