水稻秸秆降解菌BCM9的分解特性及微生物群落动态研究

李雪 葛长明 李海粟 刘双 陈迪 张本月 赵洪颜

摘要 [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BCM9，测定降解菌的分解特性和微生物群落的变化。[结果] BCM9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1.79 U/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] BCM9降解水稻秸秆的快速稳定的降解期是第9天。

关键词 水稻秸秆；微生物群落；挥发性有机酸

中图分类号 S181.3；X172 文献标识码 A 文章编号 0517-6611（2014）31-11052-03

The Dynamic of Microbial Community and Degradation Characteristics of Rice Straw by BCM9

LI Xue， GE Changming+， LI Haisu， ZHAO Hongyan* et al

（Agricultural College of Yanbian University， Yanji， Jilin 133002）

Abstract [Objective] To evaluate the potential utility of pretreatment of raw biomass with a complex microbial system. [Method] Lignocellulose was selected from biogas slurry environment to degrade strain BCM9， 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 declined 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 cellulase 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 Geobacillus sp. [Conclusion] BMC9 has a strong ability to rapidly degrade the lignocelluloses of rice straw under relatively inexpensive conditions， and the optimum fermentation time is 9 days.

Key words Rice straw； Microbial community； Volatile fatty acids

木質纤维素是地球上最为丰富的生物资源，约占植物总干重的1/3～1/2，它能够被微生物降解^[1]。秸秆是籽粒收获后耕地上重要的农业废弃物资源，吉林省每年有超过0.6亿t的秸秆废弃物资源。由于秸秆等农业废弃物资源在自然状态下极难分解，只能就地丢弃或焚烧，不能归还土壤。大量待分解的秸秆不仅占用耕地还限制营养元素归还土壤，而且焚烧产生的烟尘影响生态环境和人类健康。因此，如何将秸秆变废为宝是实现环境保护和农业可持续发展的重要课题^[2]。

崔宗均等突破传统的微生物纯培养分离方法，在不破坏自然界中微生物之间协同关系的前提下，将酸碱反应不同的菌群优化组合，筛选和驯化了高效而稳定的纤维素分解复合菌系MC1、XCD2、WDC2等复合系[1，3-4]。此复合系的降解能力远远高于纯培养的单个菌株，在8 d内可完全降解水稻秸秆^[5]。……