中国生物工程杂志

Eight biogas slurry samples were collected from some rural household biogas digesters in Sichuan, Zhejiang and Shanxi Provinces or from biogas project in Beijing. The result of biogas fermentation experiment in 500ml reaction system under different temperatures (21℃ 、18℃ and 15℃ respectively) shown that five of the samples Z-2、 Z-3、Z-6、Z-8 and Z-10 could produce biogas under different temperatures. Three of the biogas slurry samples Z-3、Z-6 and Z-10 which produce higher yield of biogas were chose for further biogas fermentation experiment in 2 500 ml reaction system under 15℃ lower temperature, a higher yield biogas fermentation system Z6 with the biogas yield of 0.15m³/m³day was selected from the three samples according to the results of two times continuous biogas fermentation experiments. The metagenomic DNA of microbial community from the Z-6 biogas fermentation system was extracted by direct extraction method, purified through Wizard DNA Clean-Up System, partial digested by Sau3AⅠand then ligated with plasmid vector of pBluescript SK (+). A metagenomic library containing 10 000 transformations was constructed, stochastic analysis of the library indicated that the average size of the foreign DNA fragments was 5 kb and the capacity of foreign DNA in the library was 48 Mb. The diversity of the restriction types of the foreign DNA fragments was higher. The results laid a foundation for utilization of gene resources of the key hydrolytic enzymes in biogas fermentation.