Characteristics of Growth and Metabolism for Methane-Oxidizing Bacterial Communities in Different Coal Samples

In recent years, microbial-mediated methane degradation, a technology represented by methane-oxidizing bacteria, has shown significant application potential in mine gas control. However, there are complicated interactions between underground coal bodies and microorganisms that can have a significant impact on bacterial community growth and metabolic activity. This study used bacterial fluids containing Xin’an (XA) and Yiluo (YL) coal samples as research subjects. The patterns of metabolic differential changes occurring during microbial growth under the effect of the coal matrix were discovered using an integrated application of gas–liquid-microbial-metabolism multi-omics analysis. The results showed that the addition of XA and YL coal samples did not significantly restrict the flora’s methane oxidation efficiency, and instead, the addition of YL coal samples promoted the flora’s methane degradation ability. The microbial community’s amino acid metabolism went through a phased transformation, with proline and cysteine dominating at first and glutamic acid, aspartic acid, and serine accumulating subsequently, indicating adaptive metabolic adaptations under hypoxia. The nitrogen-containing and sulfur-containing compounds in the coal were degraded by the microbial communities, resulting in significantly higher SO42− concentrations in the XA and YL groups compared to the CJY group, while NO3− concentrations decreased. Untargeted metabolomics analysis revealed that the addition of XA coal samples significantly affected the flora’s nitrogen metabolism pathway, whereas YL coal samples significantly promoted the flora’s sulfur metabolism, driving differential changes in metabolites such as aliphatic, peptide, purine nucleoside, benzene, heterocyclic, and organic acid metabolites as well as affecting the growth and metabolism characteristics of the microbial community and their activities. The research results have important theoretical and practical values for strengthening the theory of microbial methane degradation and enhancing the efficiency of methane-oxidizing bacteria in controlling coal mine gas.