一株产纤维素酶嗜盐真菌的分离、鉴定及发酵条件优化

Isolation and identification of a cellulase-produced halophilic fungus and process optimization of cellulase production

纤维素酶是生物燃料产业的关键酶系。本文通过刚果红染色法从腌制一年的诺邓火腿上分离到一株具有纤维素酶活性的嗜盐真菌YFCC2018SY。以形态学结合分子系统学手段对其进行鉴定,用胞外酶活测定法探索其产酶规律,并通过响应面法优化其产酶条件。结果表明该菌株属于球孢枝孢菌,且能分泌滤纸酶、内切酶和β‐葡萄糖苷酶3种嗜盐纤维素酶。响应面分析得到最优发酵条件为:NaCl含量88.58g/L、装瓶量51.21mL、起始pH 7.72。通过优化,纤维素酶活力由113.3U/mL提高到302.8U/mL,提高了167%。上述结果可以为嗜盐纤维素酶开发利用提供参考。

Cellulases are the key enzymes used in the biofuel industry. A halophilic fungus cellulase-produced,designated as YFCC2018 SY, was isolated from Nuodeng ham salted for a year by using the Congo red dye test.Identification of the strain was based on morphology and phylogenetic analysis. Extracellular enzyme activity was monitored to study the pattern of cellulase production during liquid-state fermentation by the strain. Optimum conditions of cellulase production were obtained by the response surface methodology. Strain YFCC2018 SY was identified as Cladosporium sphaerospermum, and the strain could secrete three halophilic cellulases, FPase,CMCase and β-glucosidase. The optimal conditions of the maximal activity were indicated as follows: NaCl content, 88.58 g/L;liquid volume, 51.21 mL;initial pH value, 7.72. Under the conditions, cellulase activity was increased by 167%, ranging from 113.3 to 302.8 U/mL. Our results could provide a reference for development and utilization of halophilic cellulase.