纤维降解菌系对沼气干发酵底物转化与产气的影响

The Effect of Cellulose-degrading Strains on Substrate Conversion and Gas Production in Dry Anaerobic Fermentation

该研究选育的纤维素降解菌系,在30℃酶活达到118.56 U.mL-1,水稻秸秆发酵10天的失重率可达到53.51%。试验以干牛粪与碎秸秆为底物接种该纤维素降解菌系,在TS为30%,25℃恒温条件下,发酵第15天纤维素、半纤维素降解率较对照组提高54.55%,52.83%;发酵第2天挥发性脂肪酸(VFA)为13.05 g.L-1,最终底物pH稳定在7.5左右;第7天日产气量为1440 mL,甲烷含量为66.3%。与对照组相比,处理组有效加快了干发酵中纤维类物质降解,加速VFA的生成和转化,缩短产气启动期,并且提高干发酵日产气量和甲烷含量。

The maximum enzyme activity of laboratory bred cellulose-degrading strains was 118.56 U·mL-l at 300C, under which the weight loss rate of rice straw reached 53.5% on the 10th day fermentation. With cow dung and rice straw as sub- strate and inoculated with the cellulose-degrading strains, the decomposition rate of cellulose and hemicellulose in dry fer- mentation increased by 54.55%, 52.83% respectively on the 15th day fermentation comparing with the control. Volatile fatty acids （VFA） was 13.05 g·L-1 on the 2th day, and the final substrate pH was stabled at about 7.5. The daily gas production was 1440 mL on the 7th day fermentation with methane content of 66.3%. Comparing with the control, the col- lulose-degrading strain inoculation could speed up the degradation of crude fiber in dry fermentation, accelerate the VFA formation and transforming, shorten start-up period, improve the daily gas production and methane content.