Molecular characterization of a microbial consortium involved in methane oxidation coupled to denitrification under micro-aerobic conditions.
Methane can be used as an alternative carbon source in biological denitrification because it is nontoxic, widely available and relatively inexpensive. A microbial consortium involved in methane oxidation coupled to denitrification (MOD) was enriched with nitrite and nitrate as electron acceptors under micro-aerobic conditions. The 16S rRNA gene combined with pmoA phylogeny of methanotrophs and nirK phylogeny of denitrifiers were analysed to reveal the dominant microbial populations and functional microorganisms. Real-time quantitative polymerase chain reaction results showed high numbers of methanotrophs and denitrifiers in the enriched consortium. The 16S rRNA gene clone library revealed that Methylococcaceae and Methylophilaceae were the dominant populations in the MOD ecosystem. Phylogenetic analyses of pmoA gene clone libraries indicated that all methanotrophs belonged to Methylococcaceae, a type I methanotroph employing the ribulose monophosphate pathway for methane oxidation. Methylotrophic denitrifiers of the Methylophilaceae that can utilize organic intermediates (i.e. formaldehyde, citrate and acetate) released from the methanotrophs played a vital role in aerobic denitrification. This study is the first report to confirm micro-aerobic denitrification and to make phylogenetic and functional assignments for some members of the microbial assemblages involved in MOD.
Institute of Environmental Science and Technology, Zhejiang University, Yuhangtang Road 866#, Hangzhou, 310058, China; Department of Architecture and Resources Engineering, Jiangxi University of Science and Technology Nanchang Compus, Shuanggang East Road 1180#, Nanchang, 310013, China.
Jingjing
J
Liu
Faqian
F
Sun
Liang
L
Wang
Xi
X
Ju
Weixiang
W
Wu
Yingxu
Y
Chen
D000332:Aerobiosis; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D058440:Denitrification; D008697:Methane / Q000378:metabolism*; D059013:Microbial Consortia / Q000235:genetics*; D008969:Molecular Sequence Data; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D009566:Nitrates; D009573:Nitrites; D012336:RNA, Ribosomal, 16S; D008697:Methane