title: Structure of nitrogen-converting communities induced by hydraulic retention time and COD/N ratio in constantly aerated granular sludge reactors treating digester supernatant.
abstract: This study investigated how hydraulic retention time (HRT) and COD/N ratio affect nitrogen-converting consortia in constantly aerated granules treating high-ammonium digester supernatant. Three HRTs (10, 13, 19 h) were tested at COD/N ratios of 4.5 and 2.3. Denaturing gradient gel electrophoresis and relative real-time PCR were used to characterize the microbial communities. When changes in HRT and COD/N increased nitrogen loading, the ratio of the relative abundance of aerobic to anaerobic ammonium-oxidizers decreased. The COD/N ratio determined the species composition of the denitrifiers; however, Thiobacillus denitrificans, Pseudomonas denitrificans and Azoarcus sp. showed a high tolerance to the environmental conditions and occurred in the granules from all reactors. Denitrifier genera that support granule formation were identified, such as Pseudomonas, Shinella, and Flavobacterium. In aerated granules, nirK-possessing bacteria were more diverse than nirS-possessing bacteria. At a low COD/N ratio, N2O-reducer diversity increased because of the presence of bacteria known as aerobic denitrifiers.
authors.affiliation: Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Słoneczna 45 G, 10-709 Olsztyn, Poland. Electronic address: agnieszka.cydzik@uwm.edu.pl.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Cydzik-Kwiatkowska
authors.affiliation: Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Słoneczna 45 G, 10-709 Olsztyn, Poland.
authors.forename: Paulina
authors.initials: P
authors.lastname: Rusanowska
authors.affiliation: Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Słoneczna 45 G, 10-709 Olsztyn, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Zielińska
authors.affiliation: Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Słoneczna 45 G, 10-709 Olsztyn, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Bernat
authors.affiliation: Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Słoneczna 45 G, 10-709 Olsztyn, Poland.
authors.forename: Irena
authors.initials: I
authors.lastname: Wojnowska-Baryła
mesh_terms: D000332:Aerobiosis; D000641:Ammonia / Q000378:metabolism; D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D044822:Biodiversity; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology*; D058645:Denaturing Gradient Gel Electrophoresis; D058440:Denitrification; D005798:Genes, Bacterial; D009584:Nitrogen / Q000302:isolation & purification / Q000378:metabolism*; D010084:Oxidation-Reduction; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D012722:Sewage / Q000382:microbiology*; D013045:Species Specificity; D013997:Time Factors; D018508:Water Purification / Q000295:instrumentation*
chemical_list: D012722:Sewage; D000641:Ammonia; D009584:Nitrogen
keywords: Ammonium monooxygenase (amoA gene); Anammox; Nitrite reductase (nirK; Nitrous oxide reductase (nosZ gene); Real-time PCR; nirS gene)