title: Molecular and biokinetic characterization of methylotrophic denitrification using nitrate and nitrite as terminal electron acceptors.
abstract: Although methanol is a widely employed carbon source for denitrification, relatively little is known on the abundance and diversity of methylotrophic bacteria in activated sludge. The primary aim of this study was to specifically identify bacteria that metabolized methanol in a sequencing batch denitrifying reactor (SBDR), using a novel technique, stable isotope probing (SIP) of 13C labeled DNA. A secondary aim was to quantitatively track dominant methylotrophic bacteria in the SBDR exposed to different terminal electron acceptors. SIP enabled 13C 16S rDNA clone libraries revealed that SBDR methylotrophic populations were related to Methyloversatilis spp. and Hyphomicrobium spp. Based on newly developed quantitative polymerase chain reaction (qPCR) assays, Hyphomicrobium spp. were more abundant than Methyloversatilis spp. throughout the period of SBDR operation. The relative population abundance was stable despite a shift in electron acceptor from nitrate to nitrite (keeping the same methanol dose). However, the shift to nitrite resulted in a significant decrease in denitrification biokinetics on both nitrate and nitrite.
authors.affiliation: Columbia University, Earth and Environmental Engineering, 500 West 120th Street, New York, NY 10027, USA. vb2132@columbia.edu
authors.forename: Vladimir
authors.initials: V
authors.lastname: Baytshtok
authors.forename: Sungpyo
authors.initials: S
authors.lastname: Kim
authors.forename: Ran
authors.initials: R
authors.lastname: Yu
authors.forename: Hongkeun
authors.initials: H
authors.lastname: Park
authors.forename: Kartik
authors.initials: K
authors.lastname: Chandran
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D018533:Biomass; D000432:Methanol / Q000737:chemistry* / Q000378:metabolism*; D009566:Nitrates / Q000737:chemistry* / Q000378:metabolism; D009573:Nitrites / Q000737:chemistry* / Q000378:metabolism; D010802:Phylogeny; D016133:Polymerase Chain Reaction
chemical_list: D009566:Nitrates; D009573:Nitrites; D000432:Methanol