Response of Community Structure and Activity of Methanotroph to Different CH4/O2 Ratios

AbstractBiological methane oxidation is affected by many environmental factors. In this study, 13C-labeling coupling with PLFAs detection was used to investigate the community structure of methanotrophs and the methane oxidation rate under different CH4/O2 ratios (1:1, 1:3 and 1:5 respectively). Results showed that variation of PLFAs concentration (ΔPLFAs) and carbon isotope richness (Δ13CPLFAs) of the soil incubated under the above CH4/O2 ratios (CH4 concentration: 15.6% 6.3% and 3.9% respectively) were both significant, and were positively related to the methane concentration. ΔPLFAs and Δ13CPLFAs of 16:1ω7c, 16:1ω5c and 16:0 were the most significant for all the three different incubations. The rates of oxygen consuming/methane consuming under the three incubation conditions were 1.88, 1.73 and 1.62 respectively, showing different assimilation occured. Methane oxidation rate per methanotrophic biomass calculated from 16:1ω7c, 16:1ω5c, and 16:0 were 1.11×10-7, 1.99×10-7, 1.53×10-7 nmol·h-1·cell-1 respectively