title: Effects of ammonium on the activity and community of methanotrophs in landfill biocover soils.
abstract: The influence of NH4(+) on microbial CH4 oxidation is still poorly understood in landfill cover soils. In this study, effects of NH4(+) addition on the activity and community structure of methanotrophs were investigated in waste biocover soil (WBS) treated by a series of NH4(+)-N contents (0, 100, 300, 600 and 1200mgkg(-1)). The results showed that the addition of NH4(+)-N ranging from 100 to 300mgkg(-1) could stimulate CH4 oxidation in the WBS samples at the first stage of activity, while the addition of an NH4(+)-N content of 600mgkg(-1) had an inhibitory effect on CH4 oxidation in the first 4 days. The decrease of CH4 oxidation rate observed in the last stage of activity could be caused by nitrogen limitation and/or exopolymeric substance accumulation. Type I methanotrophs Methylocaldum and Methylobacter, and type II methanotrophs (Methylocystis and Methylosinus) were abundant in the WBS samples. Of these, Methylocaldum was the main methanotroph in the original WBS. With incubation, a higher abundance of Methylobacter was observed in the treatments with NH4(+)-N contents greater than 300mgkg(-1), which suggested that NH4(+)-N addition might lead to the dominance of Methylobacter in the WBS samples. Compared to type I methanotrophs, the abundance of type II methanotrophs Methylocystis and/or Methylosinus was lower in the original WBS sample. An increase in the abundance of Methylocystis and/or Methylosinus occurred in the last stage of activity, and was likely due to a nitrogen limitation condition. Redundancy analysis showed that NH4(+)-N and the C/N ratio had a significant influence on the methanotrophic community in the WBS sample.
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
authors.forename: Jiao-Yan
authors.initials: JY
authors.lastname: Kong
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
authors.forename: Fang-Fang
authors.initials: FF
authors.lastname: Xia
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Su
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China. Electronic address: heruo@zju.edu.cn.
authors.forename: Ruo
authors.initials: R
authors.lastname: He
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism*; D058448:Biota / Q000187:drug effects*; D008697:Methane / Q000378:metabolism*; D008772:Methylococcaceae / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D042083:Methylocystaceae / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D064091:Waste Disposal Facilities
chemical_list: D064751:Ammonium Compounds; D008697:Methane
keywords: Methane oxidation; Methanotroph; NH(4)(+)-N addition; Waste biocover soil