植酸酶的激光诱变改性与分离纯化

植酸酶产生菌———黑曲霉(Aspergillus niger)可在不同的辐照条件下进行激光诱变,确定了适宜的诱变条件,即输出波长为1.06μm的Nd:YAG高重复率声光调Q激光,辐照频率4 kHz,功率10 W,水平照射2~2.5m in,并建立了变异菌株基因库。通过高通量筛选,从中筛选到一株酶学性质比较符合工业生产要求的变异菌株phy226,pH=2~3的第二酶活峰提高了40%,酶活温度稳定在30~60℃。发酵液经盐析、透析、凝胶层析和离子交换层析等分离纯化过程,最终纯化倍数达7.8,收率为25.2%。

Laser Mutation and Purification of Phytase

Phytase-producing fungus Aspergillus niger was mutated by laser radiation under different conditions.The appropriate conditions was determinated:1.06 μm Nd:YAG high repetition rate sound-optic Q-modulation laser,4 kHz,10 W power,and plane irradiation for 2~2.5 min.The mutant fungus gene bank was established.Through high flux sieving,one mutant fungus(phy226),its enzymatic properties more accordant with industrial requirement,was selected,because its second enzymatic activity apex between pH=2~3 was improved by 40% and stabilized at 30~60 ℃.The fermentation liquor was purified through salting out,dialysis,gel chromatography and ion-exchange chromatography,and 7.8-fold purification was attained with 25.2% recovery.