β-葡萄糖苷酶产生菌的选育及其性质研究

Breeding of Strain Producing β-glucosidase and Research on its Characteristics

[目的]筛选β-葡萄糖苷酶高产菌株,确定产酶的最佳工艺条件。[方法]利用几种黑曲霉进行产β-葡萄糖苷酶的筛选,得到1株β-葡萄糖苷酶高产菌株黑曲霉3.316。通过单因素和正交试验,确定产酶的最佳工艺条件,研究不同碳源(麸皮、可溶性淀粉、豆粕和米糠)在相同碳源浓度(2%)及相同发酵条件下对β-葡萄糖苷酶活力的影响。[结果]β-葡萄糖苷酶高产菌株的最佳产酶工艺条件为:麸皮2%,蛋白胨0.1%,KH2PO40.1%,初始pH值6.0。测得酶活力为152.20 U/mg。β-葡萄糖苷酶酶学性质的测定结果表明,反应液浓度为0.1 mol/L醋酸缓冲液时酶活力最高,最佳反应温度为55℃,pH为5.0。[结论]不同碳源对产酶有较大影响,麸皮做碳源时产酶最高。

[Objective] The study aimed to screen the high-yield strain of β-glucosidase and confirm the optimum technological condition of enzyme prodnction, [Method] Several species of Aspergillnse niger were screened for producing β-glucosidase and A. niger 3,316, a high-yield strain of β-glucosidase was obtained. The optimum technological condition for producing the enzyme was confirmed through single factor and orthogenal experiments and the influences of different carbon （C） sources （bran, soluble starch, soybean meal and rice bran） on β-glucosidase activity under the same C source concentration （2%） and fermentation condition. [Result] The optimum technological conditions for the high-yield strain of β-glucosidase producing the enzyme were as follows： 2% bran, 0.1% peptone and 0.1% KH2PO4 and initial pH of 6.0. The determined enzyme activity was 152.20 U/nag. The enzymological determination on β-glucosidase showed that when the reaction concentration was 0.1 mol/L acetic acid buffer, the enzyme activity was highest. The optimum reaction temperature was 55℃ and the optimum reaction pH was 5.0. [Conclusion] Different C sources had bigger influences on the enzyme production, which was highest when the C source was bran.