title: Microbial community structure and dynamics in anaerobic fluidized-bed and granular sludge-bed reactors: influence of operational temperature and reactor configuration.
abstract: Methanogenic community structure and dynamics were investigated in two different, replicated anaerobic wastewater treatment reactor configurations [inverted fluidized bed (IFB) and expanded granular sludge bed (EGSB)] treating synthetic dairy wastewater, during operating temperature transitions from 37°C to 25°C, and from 25°C to 15°C, over a 430-day trial. Non-metric multidimensional scaling (NMS) and moving-window analyses, based on quantitative real-time PCR data, along with denaturing gradient gel electrophoresis (DGGE) profiling, demonstrated that the methanogenic communities developed in a different manner in these reactor configurations. A comparable level of performance was recorded for both systems at 37°C and 25°C, but a more dynamic and diverse microbial community in the IFB reactors supported better stability and adaptative capacity towards low temperature operation. The emergence and maintenance of particular bacterial genotypes (phylum Firmicutes and Bacteroidetes) was associated with efficient protein hydrolysis in the IFB, while protein hydrolysis was inefficient in the EGSB. A significant community shift from a Methanobacteriales and Methanosaetaceae towards a Methanomicrobiales-predominated community was demonstrated during operation at 15°C in both reactor configurations.
authors.affiliation: Microbial Ecology Laboratory, Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland, Galway, Ireland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Bialek
authors.forename: Amit
authors.initials: A
authors.lastname: Kumar
authors.forename: Thérèse
authors.initials: T
authors.lastname: Mahony
authors.forename: Piet N L
authors.initials: PN
authors.lastname: Lens
authors.forename: Vincent
authors.initials: V
authors.lastname: O'Flaherty
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics*; D058448:Biota; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D003611:Dairy Products; D058645:Denaturing Gradient Gel Electrophoresis; D019649:Food Industry; D008697:Methane / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*; D013696:Temperature; D062065:Wastewater / Q000382:microbiology*; D018508:Water Purification
chemical_list: D004269:DNA, Bacterial; D008697:Methane; D012722:Sewage; D062065:Wastewater