高效纤维素分解菌的分离筛选及其分解纤维素研究

Isolation of the efficient lignocelluloses degrading microbes and decomposition of cellulose

为了从不同生境样品中分离筛选高效纤维素分解菌并评价其纤维素分解能力,以结晶纤维素为唯一碳源,测定其在刚果红平板上水解圈大小和纤维素酶活力,并分析各菌株对小麦秸秆的分解效率。结果表明:4株高效纤维素分解菌在纤维素刚果红培养基上均能形成透明水解圈,并能使滤纸条发生崩解。利用16S rRNA基因序列在GenBank中的同源性比对结果,结合其形态和生理生化特征,确定了各菌株的分类学地位,分别将其鉴定为枯草芽孢杆菌(Bacillus subtilis)X3,蜡状芽孢杆菌(Bacillus cereus)X6、55-3和55-4。接种21 h后菌株X3获得最大滤纸酶活力(0.12 U·mL-1),27 h后菌株55-4获得最大内切酶活力(3.65 U·mL-1)。与对照相比,菌株55-3接种35 d后的小麦秸秆纤维素结晶度下降了22.10%,总碳含量下降了21.20%,纤维素和半纤维素含量分别下降了44.63%和40.75%。结论:各菌株都能高效分解纤维素,在农业废弃物处理领域特别是堆肥生产中将具有较好的应用前景。

To obtain the efficient lignocelluloses degrading microbes,avicel was used as sole carbon source in the solid medium. The clear zone formatting capacities on the congo red medium and the cellulases activities in the liquid medium of different strains were also detected. The decomposition of wheat straw of different strains was carried out by evaluating cellulose crystallinity,total carbon,nitrogen,cellulose,hemicellulose and lignin contents. Results showed that all the isolated strains could form clear zone on the congo red medium and destroyed the filter paper,and these strains were identified as Bacillus subtilis X3,Bacillus cereus X6,55-3,55-4based on their physiological,biochemical characterizations and 16 S rRNA profiles. After twenty-one hours of inoculation,the maximal filter paper activity（ 0. 12 U·mL^-1） was obtained by B. subtilis X3,and maximal endoglucanases activity was detected in B. cereus55-4（ 3. 65 U·mL^-1）. By comparing with the CK,the cellulose crystallinity,total carbon,cellulose,hemicellulose and lignin contents decreased by 22. 10%,21. 20%,44. 63%,40. 75%,respectively,after inoculation of 35 days. Conclusion： All the isolated strains characterized efficient lignocelluloses degrading capacities and would have a great potential to be applied in the agricultural solid wastes treatment,especially in the composting industry.