芦苇酶解对氢气-甲烷联产过程微生物群落演替规律的影响

采用10 mg/g纤维素酶R-10预处理芦苇秸秆,研究了酶解预处理对芦苇厌氧产气潜力的影响,分析了氢气-甲烷联产过程中微生物群落结构演替规律. 结果表明:酶解预处理后,芦苇秸秆在产氢阶段的累积产气量和φ(H₂)分别达到42.5 mL/g和52.1%；在产甲烷阶段,累积产气量稳定上升,最高值可达137.5 mL/g,是对照组产气量的5倍. 由扫描电镜(SEM)观察可知,产氢阶段以短杆状和梭状菌为主,产甲烷阶段以长杆菌为主. PCR-DGGE(聚合酶链式反应-变性梯度凝胶电泳)分析表明,芦苇在酶解预处理后,其厌氧联产过程中微生物群落呈规律性演替,产氢阶段的优势微生物分别为具有降解纤维素产氢气功能的嗜热纤维素菌Clostridium thermocellum(条带B20)、具有高效产氢潜力的兼性厌氧产气肠杆菌Enterobacter aerogenes(条带B28)；在产甲烷阶段,其优势微生物为可利用氢营养途径合成甲烷的产甲烷古菌Methanoculleus bourgensis(条带A3)、Methanoculleus horonobensis(条带A13). 经纤维素酶预处理后,芦苇秸秆厌氧联产的累积产气量、φ(H₂) 提高显著,具有纤维素降解功能的细菌和可利用氢营养途径合成甲烷的古菌为主要优势微生物. 

Effects of Enzymatic Pretreatment on Microbial Community Succession in Hydrogen and Methane Coproduction from Reed Straw

Abstract: The efficiency of hydrogen and methane coproduction was investigated under enzyme pretreatment for reed straw during anaerobic fermentation. The combination of PCR amplification of 16S rDNA genes with denaturing gradient gel electrophoresis (DGGE) analysis was used to reveal the composition and succession of microbial community in coproduction process. The results showed that the maximum hydrogen production yield and proportion were 42.5 mL/g and 52.1% respectively at the hydrogenogenic stage. At the methanogenic stage, the maximum methane production of 137.5 mL/g was 5 times higher than that of the control. SEM analysis indicated that the pretreatment induced significant morphological changes. The sequences of 16S rDNA DGGE predominant bands fragments were determined by comparison with the NCBI database. At the hydrogenogenic stage, the dominant microorganism was Clostridium thermocellum (Band B20) and Enterobacter aerogenes (Band B28), which can degrade cellulose and play an important role in reed straw utilization. At the methanogenic stage, the dominant microorganism was Methanoculleus bourgensis (Band A3) and Methanoculleus horonobensis (Band A13), which can use hydrogen to synthesize methane and play an important role during the coproduction system. Hence, the maximum cumulative biogas yield and proportion were increased dramatically under 10 mg/g cellulose R-10 pretreatment. This provides an important theoretical basis for the biofortification in biogas coproduction process.