Identity of Active Methanotrophs in Landfill Cover Soil as Revealed by DNA-stable Isotope Probing

FEMS Microbiol Ecol. 2007 Oct;62(1):12-23. doi: 10.1111/j.1574-6941.2007.00368.x. Epub 2007 Aug 20.

Abstract

A considerable amount of methane produced during decomposition of landfill waste can be oxidized in landfill cover soil by methane-oxidizing bacteria (methanotrophs) thus reducing greenhouse gas emissions to the atmosphere. The identity of active methanotrophs in Roscommon landfill cover soil, a slightly acidic peat soil, was assessed by DNA-stable isotope probing (SIP). Landfill cover soil slurries were incubated with (13)C-labelled methane and under either nutrient-rich nitrate mineral salt medium or water. The identity of active methanotrophs was revealed by analysis of (13)C-labelled DNA fractions. The diversity of functional genes (pmoA and mmoX) and 16S rRNA genes was analyzed using clone libraries, microarrays and denaturing gradient gel electrophoresis. 16S rRNA gene analysis revealed that the cover soil was mainly dominated by Type II methanotrophs closely related to the genera Methylocella and Methylocapsa and to Methylocystis species. These results were supported by analysis of mmoX genes in (13)C-DNA. Analysis of pmoA gene diversity indicated that a significant proportion of active bacteria were also closely related to the Type I methanotrophs, Methylobacter and Methylomonas species. Environmental conditions in the slightly acidic peat soil from Roscommon landfill cover allow establishment of both Type I and Type II methanotrophs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Biodiversity*
  • Carbon Isotopes / metabolism
  • Cloning, Molecular
  • DNA, Bacterial / chemistry
  • DNA, Bacterial / genetics*
  • DNA, Bacterial / isolation & purification
  • DNA, Ribosomal / chemistry
  • DNA, Ribosomal / genetics
  • DNA, Ribosomal / isolation & purification
  • Isotope Labeling / methods*
  • Methane / metabolism
  • Methylococcaceae / classification*
  • Methylococcaceae / genetics
  • Molecular Sequence Data
  • Oligonucleotide Array Sequence Analysis
  • Phylogeny
  • RNA, Ribosomal, 16S / genetics
  • Sequence Analysis, DNA
  • Sequence Homology
  • Soil Microbiology*

Substances

  • Bacterial Proteins
  • Carbon Isotopes
  • DNA, Bacterial
  • DNA, Ribosomal
  • RNA, Ribosomal, 16S
  • Methane

Associated data

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