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目的:筛选降解稻草纤维素菌株,为纤维素的高效降解提供理论依据。方法:采用羧甲基纤维素钠刚果红培养基与滤纸条培养基从采集的腐木、腐土和腐叶等样品中筛选出纤维素降解菌。然后经液态发酵后测定其羧甲基纤维素酶活力与降解稻草的天然纤维素酶活力,综合考虑这两种酶活力,对其进行单独与混合发酵培养。筛选分解稻草能力较强的菌株组合。结果:初筛到5株真菌和5株细菌纤维素降解力较优的菌株。经酶活力测定后,得到分解纤维素能力较强的两株真菌F3和F5与两株细菌B1和B5,其中F3和B1的羧甲基纤维素酶活分别为705.6U、214.6U;F5和B5天然纤维素酶活分别为466.5U、204.8U。混合培养在一定程度上能提高纤维素酶活,F3/F5具有稳定而较高的酶活力,某时间段酶活高达646.8U,且后续酶活力也保持在较高水平。而F3/B5在某时间段的酶活高达788.6U。结论:菌株的混合培养可以提高纤维素酶活。
Objective: Screening and degrading straw cellulose strains provide a theoretical basis for the efficient degradation of cellulose. Methods: Cellulose-degrading bacteria were screened from samples of rotten wood, mulch and rotting leaves collected from carboxymethylcellulose sodium congo red medium and filter paper medium. Then, the activity of carboxymethylcellulose and the activity of natural cellulase of straw were measured after liquid fermentation. The activity of both enzymes was considered and the fermentation was carried out separately and mixedly. Screening strains with strong ability to decompose straw. Results: Five strains of fungi and five strains of bacterial cellulose with better biodegradability were screened out. After enzyme activity determination, two fungi F3 and F5 with strong ability of decomposing cellulose and two strains of bacteria B1 and B5 were obtained, in which the carboxymethylcellulase activities of F3 and B1 were 705.6U and 214.6U, respectively; F5 and B5 natural cellulase activity was 466.5U, 204.8U respectively. The mixed culture could improve the cellulase activity to a certain extent. The F3 / F5 had a stable and high enzyme activity. The enzyme activity was up to 646.8U in a certain period of time, and the subsequent enzyme activity was kept at a high level. The F3 / B5 enzyme activity in a certain period of time up to 788.6U. Conclusion: The mixed culture of strains can improve cellulase activity.