Study On Microbial Community Composition And Relationship With Environment In Underground Coal Mine

There are abundant and diverse microorganisms in coal seam,among which methanogenic bacteria can degrade coal under anaerobic conditions,and finally form methane gas.Methane oxidizing bacteria take methane as carbon source and use it to grow and multiply,thus reducing methane content in coal seam.Therefore,the composition of microbial community has a certain influence on the concentration of coal seam gas.A variety of environmental factors in underground coal mine cause differences in microbial community composition,and microbial life activities also change the underground environment to a certain extent,affecting the health of underground operators.Therefore,the study of different gas content and microbial community composition in different underground locations can provide a basis for methane content prediction,which is of great significance to the evolution of underground environment and the health of workers.In this paper,through high-throughput sequencing technology,the composition of in-situ bacterial and archaea communities in coal seams of high and low gas mines was determined and analyzed,to reveal the composition of underground microbial communities in coal mines with different gas content,and to explore the influence of environmental factors on the composition of microbial communities.Based on the influence of microbial life activities on methane content of coal seam and nitrogen and sulfur cycles,combined with gene function prediction,the possible influence of microorganisms on the environment can be judged according to microbial metabolic pathway,and the evolution direction of underground environment under the action of microorganisms can be predicted.The main conclusions are as follows:(1)The underground microbial diversity and richness of Yuwu coal mine in high gas mine are higher than those in low gas Xiadian coal mine,and the bacterial richness is higher than that of archaea,and the diversity and richness of Yuwu coal mine are the lowest in the heading head and 12 meters borehole.(2)The main bacteria detected included Actinobacteria,Proteobacteria,Firmicutes,cyanobacteria and Bacteroidetes,and the archaea included Halobacteria,Fluoarchaea and eurycoarchaea.The abundant cyanobacteria detected in the low gas well indicated that high gas might inhibit the growth of cyanobacteria,and the abundant actinobacteria made an important contribution to the methane content in the well.(3)The 13 environmental variables selected explained 77.11% and 64.1% of the bacterial and archaea community composition information of underground coal mine samples,respectively.Most of the environmental factors had opposite effects on methanogens and methanogens,and copper had a high correlation with bacterial and archaea community composition.(4)A large number of actinomycetes in high-gas underground have a high contribution rate to methane production and increase the underground gas content;Methane oxidizing bacteria detected in the stope face are conducive to methane reduction.The presence of sulfate-reducing bacteria will compete with methanogens,which can reduce the activity of methanogenic archaea,but the hydrogen sulfide produced is highly toxic and poses a serious threat to the health of underground personnel.