产纤维素酶菌株的分离·筛选及酶活性测定

目的]寻找更多高效降解纤维素的新菌种及其科学利用方法。方法]利用“采样－培养－分离单菌落－初筛－复筛－测OD值”的方法筛选出分解纤维素能力较强的菌株。结果]经反复培养和划线分离从80份样品中初选出35株具有分解纤维素能力的菌株。其中10株由白转绿，长势较好；6株深绿色，长势一般；4株绿色，长势较好。这20株都产孢子，被初步鉴定为绿色木霉。用刚果红培养基进行复筛选，得到9株透明圈较大的菌株。将这9株菌株再进行发酵培养，用DNS法进行酶活测定得到2株酶活较强的菌株。这2株菌株被鉴定为棘孢木霉。通过滤纸崩解测试筛选出20株降解纤维素能力较强的菌种。DNS法酶活测定结果表明采自甘蔗堆积处和甘蔗地的2个菌株的产酶活性最高。结论]采自甘蔗堆积处和甘蔗地的2个菌株可以作为降解纤维素的新菌种。

Isolation and Screening of Strains Producing Cellulase and Their Enzyme Activity Determination

Objective] The purpose was to find more new high-efficiency cellulose-decomposing strains and their utilization methods.Method] The strains with stronger cellulose-decomposing ability were screened out by the method "sampling — culture — isolation of single colony — primary screening — secondary screening — determination of OD value".Result] Thirty-five strains with cellulose-decomposing ability were isolated from 80 samples through repeated culture and streaking in primary screening.Among them,10 strains turned from white to be green and their growth potentials were better;6 strains were dark green and their growth potentials were common;4 strains were green and their growth potentials were better;all these 20 strains produced spores and were identified to be Trichoderma viride preliminarily.The congo-red media were used and 9 strains with bigger transparent circles were got in secondary screening.These 9 strains were cultured by fermentation and their enzyme activities were determined by DNS method,then 2 strains with stronger enzyme activity were got.These 2 strains were identified to be Trichoderma asperellum.Twenty strains with stronger cellulose-decomposing ability were screened out through filter-paper disintegration test.The results of enzyme activity determination by DNS method showed that the inulinase-producing activities of the 2 strains collected from the stacking place of sugar cane and sugar cane field were highest.Conclusion] The 2 strains collected from the stacking place of sugar cane and sugar cane field could be used as new cellulose-decomposing strains.