title: Microbial dynamics during azo dye degradation in a UASB reactor supplied with yeast extract.
abstract: The present work aimed to investigate the microbial dynamics during the anaerobic treatment of the azo dye blue HRFL in bench scale upflow anaerobic sludge bed (UASB) reactor operated at ambient temperature. Sludge samples were collected under distinct operational phases, when the reactor were stable (low variation of color removal), to assess the effect of glucose and yeast extract as source of carbon and redox mediators, respectively. Reactors performance was evaluated based on COD (chemical oxygen demand) and color removal. The microbial dynamics were investigated by PCR-DGGE (Polimerase Chain Reaction - Denaturing Gradient of Gel Electrophoresis) technique by comparing the 16S rDNA profiles among samples. The results suggest that the composition of microorganisms changed from the beginning to the end of the reactor operation, probably in response to the presence of azo dye and/or its degradation byproducts. Despite the highest efficiency of color removal was observed in the presence of 500 mg/L of yeast extract (up to 93%), there were no differences regarding the microbial profiles that could indicate a microbial selection by the yeast extract addition. On the other hand Methosarcina barkeri was detected only in the end of operation when the best efficiencies on color removal occurred. Nevertheless the biomass selection observed in the last stages of UASB operation is probably a result of the washout of the sludge in response of accumulation of aromatic amines which led to tolerant and very active biomass that contributed to high efficiencies on color removal.
authors.affiliation: Laboratório de Biologia e Tecnologia de Micro-organismos Departamento de Ciências Biológicas Universidade Federal de Ouro Preto Ouro PretoMG Brazil Laboratório de Biologia e Tecnologia de Micro-organismos, Departamento de Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil.
authors.forename: S Q
authors.initials: SQ
authors.lastname: Silva
authors.affiliation: Laboratório de Biologia e Tecnologia de Micro-organismos Departamento de Ciências Biológicas Universidade Federal de Ouro Preto Ouro PretoMG Brazil Laboratório de Biologia e Tecnologia de Micro-organismos, Departamento de Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil.
authors.forename: D C
authors.initials: DC
authors.lastname: Silva
authors.affiliation: Laboratório de Biologia e Tecnologia de Micro-organismos Departamento de Ciências Biológicas Universidade Federal de Ouro Preto Ouro PretoMG Brazil Laboratório de Biologia e Tecnologia de Micro-organismos, Departamento de Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil.
authors.forename: M C S
authors.initials: MC
authors.lastname: Lanna
authors.affiliation: Laboratório de Controle Ambiental Departamento de Química Universidade Federal de Ouro Preto Ouro PretoMG Brazil Laboratório de Controle Ambiental, Departamento de Química, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil.
authors.forename: B E L
authors.initials: BE
authors.lastname: Baeta
authors.affiliation: Laboratório de Controle Ambiental Departamento de Química Universidade Federal de Ouro Preto Ouro PretoMG Brazil Laboratório de Controle Ambiental, Departamento de Química, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil.
authors.forename: S F
authors.initials: SF
authors.lastname: Aquino
mesh_terms: D001391:Azo Compounds / Q000378:metabolism*; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology; D058448:Biota; D001711:Biotransformation; D016000:Cluster Analysis; D003116:Color; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D058645:Denaturing Gradient Gel Electrophoresis; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology
chemical_list: D001391:Azo Compounds; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012722:Sewage
keywords: PCR-DGGE; UASB reactor; azo dye; microbial profile; wastewater treatment