title: Characterization of bacterial structures in two-stage moving-bed biofilm reactor (MBBR) during nitrification of the landfill leachate.
abstract: Differences in DNA banding patterns, obtained by ribosomal intergenic spacer analysis (RISA), and nitrification were followed in a moving-bed biofilm reactor (MBBR) receiving municipal landfill leachate. Complete nitrification (> 99%) to nitrate was obtained in the two-stage MBBR system with an ammonium load of 1.09 g N-NH(4)/m(2).d. Increasing the ammonium load to 2.03 g N-NH(4)/m(2).d or more caused a decline in process efficiency to 70-86%. Moreover, at the highest ammonium load (3.76 g N-NH(4)/m(2).d), nitrite was the predominant product of nitrification. Community succession was evident in both compartments in response to changes in ammonium load. Non-metric multidimensional scaling (NMDS) supported by similarity analysis (ANOSIM) showed that microbial biofilm communities differed between compartments. The microbial biofilm was composed mainly of ammonia-oxidizing bacteria (AOB), with Nitrosomonas europeae and N. eutropha being most abundant. These results suggest that high ammonium concentrations select for particular AOB strains.
authors.affiliation: Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Sloneczna 45G, Olsztyn, Poland. slavcm@uwm.edu.pl
authors.forename: Slawomir
authors.initials: S
authors.lastname: Ciesielski
authors.forename: Dorota
authors.initials: D
authors.lastname: Kulikowska
authors.forename: Ewelina
authors.initials: E
authors.lastname: Kaczowka
authors.forename: Przemysław
authors.initials: P
authors.lastname: Kowal
mesh_terms: D001483:Base Sequence; D018441:Biofilms; D019149:Bioreactors / Q000382:microbiology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D014644:Genetic Variation; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000378:metabolism*; D009606:Nitrosomonas / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D021903:DNA, Ribosomal Spacer; D014874:Water Pollutants, Chemical; D009584:Nitrogen