堆肥中高温纤维素酶菌株的筛选及其酶性质研究

Screening and enzyme properties of thermophilic cellulose-decomposing bacteria from composting

从堆肥中分离获得20株耐高温纤维素分解菌,经过复筛,HC-5菌株产酶活性最高。HC-5的生长特性表明,其最适pH值为7.0,最适温度为50℃。菌株HC-5的CMCase和β-glucosidase酶作用活性范围均在40℃～70℃,但最适作用温度分别为60℃和50℃;Avicelase酶作用活性范围在40℃～60℃,而在50℃时酶作用活性最高。HC-5所产的纤维素分解酶具有良好的热稳定性,但随贮温的增加,其热稳定性呈现下降的趋势。

Twenty thermophilic cellulose-decomposing bacterial strains were selected from composting.A strain HC-5 was isolated by solid media with Congo red test in secondary screening.The optimal growth temperature and pH value of HC-5 were 50℃ and 7.0,respectively.The activities of CMCase and β-glucosidase of HC-5 could be maintained in the ranges of 40℃～70℃,while their optimal temperature was 60℃ and 50℃,respectively.The activity of HC-5 avicelase could be maintained in the ranges of 40℃～60℃,and its optimal temperature was 50℃.The cellulose-decomposing enzymes produced by HC-5 had good thermal stability,but with the storage temperature increased,the thermal stability presented a downward trend.