Exploring the Effects of Different Methane and Oxygen Concentrations on the Methane-Oxidizing Bacteria Mixed Community

Abstract

Drainage-based gas control methods will cause mine gas to be discharged into the atmosphere, causing environmental pollution and aggravating the greenhouse effect. Methane in mine gas can be oxidatively decomposed by using microbial technology, to reduce mine gas emissions and the threat of gas to mine safety. However, coal mines’ methane and oxygen concentrations change in real time. To explore the effects of different methane and oxygen concentrations on the methane-oxidizing bacteria mixed community, a methane-oxidizing bacteria mixed community was enriched and cultured from mine soil samples in this study, and its community structure, cell morphology, and methane degradation ability were analyzed. The results showed that the methane-oxidizing bacteria Methylomicrobium accounted for 55.6% of the total, Cloacibacterium accounted for 19.39%, and Methylophilus accounted for 10.3%. The methane degradation rate of the mixed community can reach 29.98 μmol mL−1 d−1. Using the Michaelis–Menten kinetic equation analysis, it was found that the methane degradation effect was the highest when the methane concentration was 1%–20%, and the maximum methane oxidation rate could reach 57.078 μmol mL−1 d−1. When the oxygen concentration ranged from 1% to 50%, the methane degradation ability of methanotrophs gradually increased with the increase of oxygen concentration.