Actinobacteria may influence biological methane generation in coal seams. (1st May 2023) - Li, Yang
Highlights: Actinobacterial diversity and copy number were closely related to methanogenic potential. Propionibacterium was the biggest contributor to methanogenic potential. Actinobacteria indirectly affect methanogenic potential by controlling negative cohesion. Abstract: Microorganisms are the core drivers of coal biogeochemistry and are closely related to biological coalbed methane. However, the Actinobacterial taxa in coals and their roles in the context of biological coalbed methane remain poorly understood. In this study, 16S rRNA gene sequencing and quantitative PCR were used to analyze the Actinobacterial taxa and abundance in coals from different regions of China. The results indicated that Proteobacteria was the predominant bacterial phylum, and Actinobacteria accounted for only 1.64 % of the coal bacterial communities. However, Actinobacteria was the largest contributor to methanogenic potential, followed by Firmicutes and Cyanobacteria. The Shannon diversity, structure and absolute abundance of Actinobacteria were closely related to methanogenic potential. In addition, widely detected genera included Propionibacterium, Corynebacterium, Brevibacterium, Arthrobacter, Micrococcus, Phycicoccus and Brachybacterium, all of which belong to the order Actinomycetales. Among them, Propionibacterium was the most important genus contributing to the methanogenic potential, followed by Corynebacterium and Phycicoccus . In the microbial co-occurrence network, actinobacterial-related nodes and links accounted for 18.29 % and 33.16 % of the total nodes and links, respectively, and actinobacterial OTUs belonging to the genera Propionibacterium, Corynebacterium, Arthrobacter, Dietzia, Phycicoccus, Rhodococcus and Micrococcus were identified as connectors. Furthermore, partial least squares path modeling indicated that Actinobacteria can affect methanogenic potential indirectly by controlling community negative cohesion. In summary, Actinobacteria appear to play important roles in maintaining the microbial co-occurrence network and regulating coal biological methanogenic potential, which is help to understand the coal microbial ecology and geochemical processes.