title: Impact of oxygen on the coexistence of nitrification, denitrification, and sulfate reduction in oxygen-based membrane aerated biofilm.
abstract: Membrane aerated biofilms (MABs) are subject to "counter diffusion" of oxygen and substrates. In a membrane aerated biofilm reactor, gases (e.g., oxygen) diffuse through the membrane into the MAB, and liquid substrates pass from the bulk liquid into the MAB. This behavior can result in a unique biofilm structure in terms of microbial composition, distribution, and community activity in the MAB. Previous studies have shown simultaneous aerobic oxidation, nitrification, and denitrification within a single MAB. Using molecular techniques, we investigated the growth of sulfate-reducing bacteria (SRB) in the oxygen-based MAB attached to a flat sheet membrane. Denaturing gradient gel electrophoresis of the amplified 16S rRNA gene fragments and functional gene fragments specific for ammonia-oxidizing bacteria (amoA), denitrifying bacteria (nirK), and SRB (dsrB) demonstrated the coexistence of nitrifiers, denitrifiers, and SRB communities within a single MAB. The functional diversities of SRB and denitrifiers decreased with an increase in the oxygen concentration in the bulk water of the reactor.
authors: Department of Civil and Environmental Engineering, Faculty of Engineering, University of Alberta, Edmonton, AB T6G 2W2, Canada.
authors: Hong
authors: H
authors: Liu
authors: Shuying
authors: S
authors: Tan
authors: Zhiya
authors: Z
authors: Sheng
authors: Tong
authors: T
authors: Yu
authors: Yang
authors: Y
authors: Liu
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D019149:Bioreactors / Q000382:microbiology*; D058645:Denaturing Gradient Gel Electrophoresis; D058440:Denitrification; D008567:Membranes, Artificial; D058465:Nitrification; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D013431:Sulfates / Q000378:metabolism*
chemical_list: D008567:Membranes, Artificial; D013431:Sulfates; D010100:Oxygen
keywords: PCR–DGGE; bactéries sulfatoréductrices; biofilms aérés à membrane; diversité fonctionnelle; functional diversity; membrane aerated biofilms; sulfate-reducing bacteria