一株纤维素酶真菌的筛选鉴定及产酶条件优化

以羧甲基纤维素钠为唯一碳源，从自然界筛选出一株纤维素酶高产菌HJC-79，通过单因素试验和正交试验对其培养基成分和发酵条件进行优化。结果表明，经形态观察和ITS序列分析，菌株HJC-79被鉴定为杂色曲霉（Aspergillus versicolor）。最佳培养基成分为蔗渣、麸皮和Mandels营养盐液的添加量分别为2%、9%、89%；最佳发酵条件为发酵温度33 ℃，初始pH值为4，接种量9.0%，发酵时间48 h。在此优化条件下，葡聚糖内切酶、β-葡萄糖苷酶和滤纸酶酶活分别为2.22 U/mL、1.93 U/mL、1.53 U/mL，分别比优化前提高了125.55%、76.37%和172.47%。

Screening and identification of a cellulase-producing strain and optimization of cellulase-producing condition

Using sodium carboxymethyl cellulose as sole carbon source, a high yield cellulose strain HJC-79 was isolated from nature. The medium composition and fermentation conditions were optimized by single factor experiment and orthogonal experiments. Results showed that after morphological observation and ITS sequence analysis, the strain HJC-79 was identified as Aspergillus versicolor. The optimal medium composition was bagasse 2%, bran 9% and Mandels nutrient solution 89%. The optimum fermentation conditions were fermentation temperature 33 ℃, initial pH value 4, inoculum 9.0%, and fermentation time 48 h. Under the optimized conditions, the activity of dextran endonuclease, β-glucosidase and filter paper enzyme were 2.22 U/ml, 1.93 U/ml and1.53 U/ml, respectively, which were 125.55%, 76.37% and 172.47% higher than those before optimization.