产纤维素酶真菌菌株的分离筛选及产酶条件优化

Isolation and screening of fungi strains producing cellulase and optimization of conditions for enzyme production

【目的】由于真菌的纤维素酶系较全,且可分泌至胞外,易分离,所以试验致力于筛选高产纤维素酶真菌菌株.【方法】利用羧甲基纤维素钠培养法、刚果红染色法、纤维素酶活性测定法从样品中分离筛选出产纤维素酶菌株,同时结合菌落形态观察、显微镜观察和ITS序列同源性分析进行鉴定.【结果】通过初筛,筛选出15株Hc值较大的产纤维素酶真菌菌株,再经过液体发酵复测羧甲基纤维素酶活和滤纸酶活,筛选出一株产纤维素酶活最高的菌株B-2-3,经鉴定B-2-3为烟曲霉（Aspergillus fumigatus）,其羧甲基纤维素酶活为2 341.76U/mL,滤纸酶活为398.18U/mL.经过产酶条件优化,确定其最适产酶条件为温度25℃、接种量4μL、蛋白胨0.5~0.6g/L、CMCNa 0.3~0.35g/L、pH 6.5.【结论】筛选出一株产纤维素酶活较高的烟曲霉菌株B-2-3.

[Objective] Using fungi to screen fungal strains with high cellulases activity because it has large cellulase enzymes, can be secreted into the extracellular and easily be separated. [Method] Sodium carboxymethyl cellulose culture,Congo red staining, cellulase activity assays were used to isolate and screen strains producing cellulose from samples, and identification was conducted combining with colony morphol- ogy,microscopic characteristics and ITS sequence homology analysis. [Result] 15 fungal strains producing cellulases with higher He value was screened, through liquid fermentation retest CMC activity and filter pa- per activity, screening a strain B-e-a producing the highest cellulase activity, and it was identified as Asper- gillus fumigatus with the CMC activity of 2 341.26 U/mL and filter paper activity of 398. 18 U/mL. The optimum conditions for enzyme production were as follows： temperature of 25℃,inoculation of 4uL, pep- tone of 0. 5--0.6 g/L,CMC-Na of 0. 3---0. 35 g/L,pH of 6.5. [Conclusion] Aspergillus strains B-2-3 was screened with higher production of cellulase activity.