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产氢细菌是厌氧发酵过程中重要的功能微生物.将分离自纤维素降解产甲烷复合菌系FSC的产氢细菌FSC-15回补至复合菌系,通过监测氢气产量、甲烷产量、脂肪酸浓度及秸秆降解效率,探究产氢细菌对水稻秸秆水解产甲烷代谢及微生物群落结构的影响.结果显示:添加菌株FSC-15使FSC中纤维素、半纤维素和木质素降解率分别提高了17.33%、28.61%和47.21%,对复合菌系FSC中秸秆降解效率有一定促进作用.培养第3天,氢气产量相比复合菌系FSC提高了41.18%,为产甲烷菌提供更充足的底物,使甲烷产量提高1倍.高通量测序结果显示,Ruminococcaceae和Methanobacteriaceae分别是水稻秸秆厌氧发酵产甲烷体系中水解纤维素和产甲烷的主要类群,Methanobacteriaceae是厌氧发酵体系挥发酸含量较高时产甲烷的主要物种,补加产氢细菌FSC-15对厌氧降解纤维素产甲烷菌系中的细菌群落结构无明显影响,但可以改变古菌的物种多样性及丰度.本研究证明向水稻秸秆厌氧发酵体系补加功能微生物能有效提高体系甲烷产量,可为调控水稻秸秆厌氧消化技术提供理论支撑.
Hydrogen-producing bacterium is an important functional microorganism during anaerobic fermentation.The hydrogen-producing bacterium FSC-15 isolated from cellulolytic methanogenic complex strain FSC is replenished to the complex strain by monitoring the hydrogen production, methane production, fatty acid concentration And the degradation efficiency of straw to explore the effects of hydrogen-producing bacteria on methane metabolism and microbial community structure during rice straw hydrolysis.The results showed that the strain FSC-15 enhanced the degradation rate of cellulose, hemicellulose and lignin by 17.33% , 28.61% and 47.21% respectively, which promoted the degradation efficiency of straw in composite strain FSC.At the third day, hydrogen production increased by 41.18% compared with the composite strain FSC, which provided a more adequate substrate for methanogens, And the yield of methane increased by 1 times.The results of high-throughput sequencing showed that Ruminococcaceae and Methanobacteriaceae were the main groups for hydrolyzing cellulose and methanogenic in the methane production system of rice straw anaerobic fermentation, Methanobacteriaceae was the high volatile acid content in the anaerobic fermentation system The major methane-producing species, supplemented with hydrogen-producing bacterium FSC-15, had no significant effect on the bacterial community structure in methanogenic strains of anaerobically degraded cellulose, Archaea species diversity and abundance.This study shows that rice straw anaerobic fermentation system supplemented with functional microorganisms can effectively improve methane production system, which can provide theoretical support for the regulation of rice straw anaerobic digestion technology.