Mechanism of methane oxidation by methanotrophs and effect of soil moisture content on their activity

The paper reviews the mechanism of methane oxidation by methanotrophs in soils and influence of soil moisture content on methanotrophic function．Four steps are included in the process of methane oxidation in soils．Methane is first oxidized to methanol by sMMO or pMMO and then the latter is further transformed into formaldehyde by methanol dehydrogenase，which is the carbon source of methanotrophic cell syntheses and can be assimilated through RuMP pathway and serine pathway by Type I and Type II methanotrophs，respectively．Type II methanotroph contains both sMMO and pMMO but Type I only pMMO．so Type II methanotroph can survive better in environments where nutrients such as nitrogen，copper are limited．The maximum rate of methane oxidation by methanotroph exists in soil subsurfaces and is mostly influenced by soil moisture content，which is，in turn，mainly dependent on soil texture，soll organic matter and so on．