β-葡聚糖酶和木聚糖酶高产菌株的选育及在小麦加工中的应用

Screening of mutant with high yield of both β-glucanase and xylanase and its application in wheat processes

以Aspergillus nigerJ5为出发菌株,经Co60γ-射线诱变,筛选到一株β-葡聚糖酶和木聚糖酶活力都较出发菌株高的突变株A-25,其产β-葡聚糖酶和木聚糖酶的合适发酵条件为:大麦粉4%、玉米浆2.5%、NaNO30.4%、Na2HPO40.1%、MgSO4.7H2O0.03%、FeSO4.7H2O0.01%、CaCO30.5%、吐温-800.25%,初始pH6.7,300mL三角瓶的装液量为50mL,在此条件下培养84h,β-葡聚糖酶活力达到1203.9I U/mL,较出发菌株提高35.9%,木聚糖酶活力达到395.2I U/mL,较出发菌株提高27.8%。突变株粗酶液降解工业面粉非淀粉多糖的能力明显高于出发菌株。

A mutant strain, designated as A-25, with higher yield of both β-glucanase and xylanase was screened from the start strain Aspergillus niger J5 treated by Co^60γ-rays, and its optimal fermentation conditions for β-glucanase and xylanase production were as follows： barley powder 4 %, maize slurry 2.5 %, NaNO3 0.4 %, Na2 HPO4 0.1%, MgSO4· 7H2O 0.03 %, FeSO4 ·7H2O 0.01%, CaCO3 0.5 %, polysorbate-80 0.25 %, the initial pH 6.7, 50mL culture media per 300mL-flask. After A-25 was cultivated under these conditions for 84 h, its β-glucanase activity reached 1203.9 IU/ mL, 35.9% higher than the orginal strain, while its xylanase activity reached 395.2 IU/mL, 27.8% higher than the orginal one. The crude enzyme of the mutant A-25 had remarkably higher ability to degrade the non-starch polysaccharide in the industrial flour than that of the orginal strain.