水稻秸秆降解菌BCM-9的分解特性及微生物群落动态研究

The Dynamic of Microbial Community and Degradation Characteristics of Rice Straw by BCM-9

[目的]探索复合微生物菌系前处理秸秆生物质资源的潜能。[方法]从沼液环境中筛选木质纤维素降解菌株BCM-9,测定降解菌的分解特性和微生物群落的变化。[结果]BCM-9的快速降解期是0~9 d;pH的变化是先降低后升高之后趋于稳定;在第9天时,挥发性脂肪酸浓度,木聚糖酶活和纤维素酶活值最高,乳酸0.291 mg/L,甲酸0.31 mg/L,乙酸1.93 mg/L,丙酸0.73 mg/L,木聚糖酶活1.79U/ml,纤维素酶活0.37 U/ml;微生物群落的多样性也最丰富,属于Clostridium sp.、Bacillus sp.、Geobacillus sp.。[结论]BCM-9降解水稻秸秆的快速稳定的降解期是第9天。

[ Objective ] To evaluate the potential utility of pretreatment of raw biomass with a complex microbial system. [ Method ] Lignocel- lulose was selected from biogas slurry environment to degrade strain BCM-9, the degradation properties of the bacteria and microbial community change was determined. The degradation characteristics and corresponding changes in the bacterial community were assessed. [ Result ] The results showed that rapid degradation occurred from day 0 to day 9. The pH of the fermentation broth initially dechned and then increased, and the mass of rice straw steadily decreased. The highest concentrations of volatile fatty acid contents （0.291 mg/L lactic acid, 0.31 mg/L formic acid, 1.93 mg/L acetic acid, and 0.73 mg/L propionic acid） as well as the highest xylanse activity （1.79 U/ml） and carboxymethyl eellulase activity （0.37 U/ml） occurred on day 9. The greatest diversity among the microbial community also occurred on day 9, with the presence of bacteria belonging to Clostridium sp., Bacillus sp., and GeobaciUus sp. [ Conclusion] BMC-9 has a strong ability to rapidly degrade the lignocelluloses of rice straw under relatively inexpensive conditions, and the optimum fermentation time is 9 days.