植酸酶的激光诱变改性与分离纯化

Laser Mutation and Purification of Phytase

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1.06 μm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2～2.5 min,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%.

Phytase-producing fungus Aspergillus niger was mutated by laser radiation under different conditions. The appropriate conditions was determinated ： 1.06μm Nd ： YAG high repetition rate soundoptic Q-modulation laser,4 kHz, 10W 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 fermentationliquor was purified through salting out, dialysis, gel chromatography and ion-exchange chromatography, and 7.8-fold purification was attained with 25.2% recovery.