白曲霉Asp-amy1固体发酵生产酸性淀粉酶的初步研究

Study on Solid Fermentation by Use of Aspergillus candidus Strain Asp-amy1 to Produce Acidic α-amylase

利用白曲霉菌株Asp-amy1进行固体发酵生产酸性淀粉酶,对白曲霉固体发酵条件进行了优化,初步确定菌株产酶的优化培养基为:7.5%的玉米粉,1.5%的蛋白胨,发酵曲含水量为50%,发酵起始pH5.5。菌株的最佳接种量为40%(干基计),发酵时间由72h缩短到48h,菌体生长迅速,产酶能力强,酶活达1000U/g干曲。薄层层析生成的液化产物,主要以G2-G7为主,淀粉液化后都生成了小分子的糊精和寡糖类;产物薄层分析可初步确定所产酶为液化型酶。

Aspergillus candidus strain Asp-amyl was used in solid fermentation to produce acidic α-amylase. The solid fermentation conditions were optimized and the culture medium was preliminarily determined as follows： 7.5 % maize meal, 1.5 % peptone, moisture content of fermenting starter was 50 %, and the initial pH value was 5.5. The best inoculation quantity of the strain was 40 %, the fermentation time shortened from 72 h to 48 h, and the activity of acidic α-amylase could reach up to 1,000 U/g dry substrate. The liquefying products by TLC analysis （mainly including G2-G7） would develop to dextrin and oligosaccharide. And TLC analysis proved preliminarily that the produced acidic α-amylase was a kind of liquefying amylase.