Isolation Of Biogas Fermentation Low-temperature Function Microorganism And Study In Promotion Biogas Fermentation In The Low-temperature

The temperature is the important factor that affect biogas fermentation. Low-temperature restricts the efficiency of biogas fermentation.It is overwintering practical significance of promoting the efficiency of the low temperature biogas fermentation and coping with methanogenesis in low temperature environment.The research achievements (1) A strain of cold-adapted, anaerobic bacteria degrading cellulose efficiently was isolated from pelouse sludge of Zoige wetland of Tibetan plateau. The isolated cells were straight rods that were 0.3μm×2.8 ~ 3.1μm, G—, strictly anaerobic. The range of growth temperature is 5℃~ 40℃(the optimum is 20℃);The pH ranges between 6.5 ~ 8.0(the optimum is 7.0);The NaCl% ranges between 0.1% ~ 0.4%(the optimum is 0.2%). The isolates could degrade cellulose filter paper, cellulose powder MN300, microcrystalline cellulose, carboxymethyl cellulose sodium, hydroxyethylcellulose and xylan. The optimum temperature of C1,Cx andβ-glucosidase was 30℃,30℃and 25℃. Xylanase was detected and the optimum temperature is 30℃. The phylogenetic analysis based on 16S rDNA suggested that strain CD-2 was the closest relative of C. Papyrosolvens with 99 % sequence similarity and was identified as a species Clostridium. (2) In promoting biogas fermentation experiments, the experimental group adding Methanococcoides burtoni(iDSM 6242)is the best result in all experimental group, followed by cellulose degradation bacterium P4-3 experimental group. The methane content of the two experimental group after steady fermentation are 56%. Compared to the control group,gross gas of adding DSM 6242 experimental group was increased by 46.8 %,and gas production per day was 66.7% in maximum. Compared to the control group, gross gas of adding cellulolytic anaerobic bacterium P4-3 experimental group was increased by 28.7% .The gas production per day was 55.6% in maximum. With the analysis of DGGE, we can find that the common dominance genus of 15℃and 35℃fermentation samples was Methanosarcina. The typical dominance genus of 15℃fermentation sample and 35℃fermentation samples was Methanocorpusculum and Methanomicrobium. Adding strain DSM 6242 and P4-3 will affect the microbial community structure and biomass of archaeal/bacterial. The dominance genus of adding DSM 6242 experimental group were Methanocorpusculum and Methanosarcina, and appeared Methanomicrobium in the 27th day in culture.