一株产蛋白酶芽孢杆菌紫外诱变育种的初步研究

Preliminary study on the ultraviolet mutagenesis of a protease producing strain Bacillus Amyloliquefaciens

水产品加工废弃物容易造成环境污染,但其富含蛋白质,如果加以充分利用可以减少环境污染和提高经济效益。目前,抗氧化肽已经得到了广泛的应用,已经筛选了1株解淀粉芽孢杆菌Hy-7,以其发酵水产加工废弃物得到了较高的抗氧化肽产率。以此为出发菌,采用紫外线诱变的方法筛选出1株蛋白酶活力较高的菌株Hy-743,以鲅鱼加工后的废弃物为原料,接种该菌株进行发酵。该突变株较未经紫外线诱变的出发菌蛋白酶活力提高了40.1%,酶解物总抗氧化活性提高了10.2%。经遗传稳定性测定,该突变株在传代8次之后其遗传稳定性仍然良好。对菌株Hy-743进行响应面法优化发酵条件,得到最佳发酵条件为发酵温度30℃、发酵时间48 h、培养基初始p H6.6、菌龄26 h,接种量2%、料液比1.7 g/50 m L。筛选出的菌株酶活力较强、遗传稳定性好,可以用于发酵水产品及其加工废弃物制取抗氧化肽。

Aquatic products leftover material after processing are rich in protein, and the leftover material usually,tend to be abandoned.This leads to the protein waste and environmental pollution.In order to utilize this kind of protein, one strain （Hy-743） producing high protease was obtained through mutation of Bacillus Amyloliquefaciens Hy-7 by ultraviolet mutagenesis, The protein hydrolysates had certain antioxidant activity inoculating mutant strain Hy-743 using waste proteins of Spanish mackerel production as substrate. Compared with that of the initial strain , the enzyme activity of the mutant strain increased by 40 .1%, and the total antioxidant activity of the protein hydrolysates increased by 10.2%.The ability to produce enzyme of the mutant strain Hy-743 showed high stability after 8 generations.Using the response surface method to optimize strain Hy-743 for the fermentation conditions, the optimal fermentation conditions are：fermentation temperature 30 ℃, fermentation time for 48 h, initial pH of 6.6, fungus age of 26 h, 2%inoculated quantity, and solid-liquid ratio 1.7 g/50 mL.In clusion, this high yield strain has high protease activity and good genetic stability, and can be used for preparing antioxidant.