Real-time monitoring of methane oxidation in a simulated landfill cover soil and MiSeq pyrosequencing analysis of the related bacterial community structure

Abstract Real-time CH 4 oxidation in a landfill cover soil was studied using automated gas sampling that determined biogas (CH 4 and CO 2 ) and O 2 concentrations at various depths in a simulated landfill cover soil (SLCS) column reactor. The real-time monitoring system obtained more than 10,000 biogas (CH 4 and CO 2 ) and O 2 data points covering 32 steady states of CH 4 oxidation with 32 different CH 4 fluxes (0.2–125 mol·m −2 ·d −1 ). The kinetics of CH 4 oxidation at different depths (0–20 cm, 20–40 cm, and 40–60 cm) of SLCS were well fit by a CH 4 -O 2 dual-substrate model based on 32 values (averaged, n = 5–15) of equilibrated CH 4 concentrations. The quality of the fit ( R 2 ranged from 0.90 to 0.96) was higher than those reported in previous studies, which suggests that real time monitoring is beneficial for CH 4 oxidation simulations. MiSeq pyrosequencing indicated that CH 4 flux events changed the bacterial community structure (e.g., increased the abundance of Bacteroidetes and Methanotrophs) and resulted in a relative increase in the amount of type I methanotrophs ( Methylobacter and Methylococcales ) and a decrease in the amount of type II methanotrophs ( Methylocystis ).