适用于饲料行业的产酸性纤维素酶的黑曲霉诱变菌株

Mutant Strain of Aspergillus niger Producing Cellulase Suitable for Feed Industry

针对饲料工业对纤维素酶酶学特性的特殊要求,为得到一株适用于饲料工业且高产酸性纤维素酶的黑曲霉菌种。用0.1%浓度的硫酸二乙酯对一株产酸性纤维素酶的黑曲霉菌种诱变15min,经诱变筛选培养基上透明圈大小的初筛,再将初筛得到的诱变种子,经种子斜面培养基分离活化,摇瓶种子培养基扩培,摇瓶筛选培养基培养后,测定摇瓶发酵液的酶活,复筛高产菌株,最终得到一株酶活水平最高的黑曲霉诱变菌株YB-5628。对该菌株进行种子斜面培养基分离活化,摇瓶种子培养基扩培,种子罐培养基扩培,发酵罐培养基发酵,测定发酵罐最高酶活水平为2062U/mL,较出发菌株提高了1.2倍。对发酵所得的酸性纤维素酶进行酶学特性研究,该诱变菌株所产酸性纤维素酶,在40℃-65℃范围内保持80%以上的酶活。在pH3.8-4.8范围内,能保持80%以上的酶活。该酶学特性符合饲料酶制剂的要求,高发酵酶活水平可使发酵成本进一步降低,能广泛的应用于畜牧及食品行业,提高这些行业的产品竞争力,促进高效绿色的可持续发展。

According to the special requirements of cellulase enzymatic characteristics in feed industry,in order to obtain a Aspergillus niger strain suitable for feed industry and high acid cellulase.A strain of Aspergillus niger Producing acid cellulase was mutated with diethyl sulfate at the concentration of 0.1% for 15 min.the mutagenic screening medium was used for the preliminary screening of the size of the transparent circle on the medium,and then the mutagenic seeds obtained from the preliminary screening were separated and activated by the seed inclined medium,expanded in the shake flask seed medium,cultured in the shake flask screening medium,the enzyme activity of the shake flask fermentation broth was measured,and the high-yield strain was re screened.Finally,a mutant strain yb-5628 of Aspergillus niger with the highest enzyme activity was obtained.The strain was isolated and activated in seed inclined medium,expanded in shake flask seed medium,expanded in seed tank medium and fermented in fermentation tank medium.The highest enzyme activity level in fermentation tank was 2062u/ml,which was 1.2 times higher than that of the original strain.The enzymatic characteristics of the acid cellulase produced by fermentation were studied.The acid cellulase produced by the mutant strain maintained more than 80%of the enzyme activity in the range of 40℃-65℃.It can maintain more than 80%enzyme activity in the range of pH 3.8-4.8.The enzymatic characteristics meet the requirements of feed enzyme preparation.High fermentation enzyme activity level can further reduce the fermentation cost.It can be widely used in animal husbandry and food industries,improve the product competitiveness of these industries and promote efficient,green and sustainable development.