[ Objective J The aim was to isolate and identify a thermostable cellulose degrading strain and study its enzymatic characteristics. [ Method] The cellulose degrading strain was isolated from rotten straw and humus by Congo red method,and then it was identified by its morphological properties and 16S rRNA sequence analysis. And its enzymatic characteristics were studied. [Result] A bacteria strain NP29 producing thermostable cellulase was isolated and was identified as a Racillus. Studies on enzymatic characteristics of this strain showed that the optimum pH value was 4. 5 and the optimum reaction temperature was 65 ? ,this cellulaae had a higher pH stability and thermal stability. The highest cellulose activity of strain NP29 was 1.8 U/ml when growing at 37 ?. and pH 7.0 for 36 h ,the generation of this cellulase was closely related to its growth rate. [ Conclusion]The study provides references for the use of cellulase resources.%[目的]筛选耐热性纤维素降解细菌菌株,进行鉴定并研究其酶学特性.[方法]采用刚果红法从腐烂秸秆与腐殖质土壤样品中分离纤维素降解菌,通过形态学观察与16S rRNA序列分析鉴定其种属,并对该纤维素酶进行酶学性质研究.[结果]筛选到1株纤维素酶活性高的菌株NP29,经鉴定该菌株为芽孢杆菌属(Bacillus)微生物.对该菌所产纤维素酶酶学特性的研究表明,该酶反应的最适pH为4.5,最佳反应温度为65℃,具有良好的pH稳定性和热稳定性.在37℃、pH7.0的条件下,该菌株在发酵36 h后纤维素酶活性可达1.8 U/ml,且产酶量与细菌生长密切相关.[结论]
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