Characterization Of The Action Of Different Hydrolytic Bacteria On Long-flame Coal

The hydrolysis efficiency of the hydrolysis stage,as the first stage of anaerobic fermentation,will determine the bioavailability of coal.However,since anaerobic fermentation involves a wide range of bacterial species,the degradation function of coal by each genus and the conjugation relationship between the genera are the key factors affecting the hydrolysis efficiency.In this paper,the relevant studies were carried out in three aspects: the study of the degradation characteristics of different single bacteria on long-flame coal,the study of the metabolic variability of high-efficiency hydrolytic bacteria,and the study of the action characteristics of different hydrolytic bacteria and compound bacterial agents on long-flame coal,and the following conclusions were obtained:(1)By comparing the degradation of long-flame coal by different single bacteria,it was found that: the hydrolytic bacteria mainly acted on the hypomethylene in the fat structure,the-OH Jian in the carboxylic acid and the C=C in the benzene ring;Bacillus polymyxa,Pseudomonas aeruginosa and Bacillus sp.had obvious degradation effect on the hypomethylene in the fat structure of long-flame coal;the liquid phase products of Bacillus polymyxa and Pseudomonas aeruginosa were mainly hydrogenated cinnamic acid and small molecular acid;Bacillus polymyxa and Pseudomonas aeruginosa had both hydrolysis and acidification functions,and could participate in the anaerobic fermentation process of coal gas as both hydrolysis and acidification bacteria.(2)The metabolomic analysis of efficient hydrolysis bacteria revealed that: the metabolites of the hydrolysis stage of coal to methane were mainly organic acids,aromatic compounds and coenzymes;the dominant metabolites of Bacillus polymyxa were amine organic compounds,and Bacillus polymyxa had the strongest ability to transport amino acids and proteins;the metabolites of Pseudomonas aeruginosa had the highest relative content of coenzymes;the dominant metabolites of Bacillus were organic acids,and their degradation products had the highest content of macromolecular compounds,and Bacillus polymyxa had the highest differential abundance score.(3)By comparing the degradation of long-flame coal by single bacteria and composite bacterial agents,we found that: the sample with the highest total gas production was degraded by the combination of Bacillus immobilis and Pseudomonas aeruginosa,with the total gas production of 19.86 m L/g.The sample with the highest total methane production was treated by Pseudomonas aeruginosa,with the total methane production of 10.78 m L/g;the degradation by the combination of Bacillus immobilis and Pseudomonas aeruginosa showed the degradation characteristics of Bacillus immobilis.The combined degradation of Bacillus immobilis and Bacillus polymyxa weakened the degradation effect on aromatic C=C bond and lost the degradation ability on OH bond and single-neighboring aromatic C-H Jian in carboxylic acid;the combined degradation of Pseudomonas and Bacillus polymyxa weakened the degradation effect on OH bond and single-neighboring aromatic C-H Jian in carboxylic acid;the specific surface area and total pore volume of coal samples treated by different single bacteria and compound bacterial agents generally decreased The specific surface area and total pore volume of the coal samples treated with different single bacteria and composite agents were generally reduced,and the largest reduction was in the coal samples degraded by Pseudomonas aeruginosa.The study of the conjugation relationship between different hydrolytic bacteria as well as the strains of composite agents is beneficial to the screening of efficient functional bacteria for the construction of methanogenic functional microbial agents,and to the enrichment of coal-to-biogas theory.