高产酯化酶红曲菌的筛选、鉴定及酶学性质研究

Screening and identification of high-yield esterase Monascus and the enzymatic property

该研究从研究室保藏的10株红曲霉菌株中筛选高产酯化酶菌株,通过分子生物学技术对其进行鉴定,并对其最适培养基进行选择,最后对其所产的酯化酶酶学特性进行初步研究。结果表明,筛选获得一株高产酯化酶菌株X1,并被鉴定为血红红曲霉(Monascus sanguineus)。其最适产酶培养基为可溶性淀粉70 g/L,大豆蛋白胨20 g/L,NaNO3 2 g/L,KH2PO4 1 g/L,MgSO4·7H2O 2 g/L,初始pH值4.5。采用最优培养基,在30 ℃、180 r/min条件下发酵4 d,酯化酶活力为315.19 U/mL。该酯化酶的最适反应温度为40 ℃,在25~35 ℃范围内稳定性较好;最适pH值为5.0,在pH为6.0时稳定性较高;金属离子Ca2+可提高该酯化酶活性,Mg2+、Fe2+、Na+和Ag+则有不同程度抑制作用,且Ag+抑制作用最明显。

A high-yield esterase Monascus was screened from 10 Monascus strains in the laboratory and identified by molecular biology technology, the optimal medium was screened, and the enzymatic properties of esterase produced by Monascus were preliminary studied. The results showed that a high-yield esterase Monascus strain X1 was screened and was identified as Monascus sanguineous. The optimum medium for esterase production was soluble starch 70 g/L, soybean peptone 20 g/L, NaNO3 2 g/L, KH2PO4 1 g/L, MgSO4·7H2O 2 g/L and initial pH 4.5. The strain was fermented for 4 d at 30 ℃ and 180 r/min in the optimal medium, the esterase activity was 315.19 U/ml. The optimum reaction temperature of the esterase was 40 ℃, and the stability was better at 25-35 ℃. The optimum reaction pH value was 5.0, and the stability was better at 6.0. The metal ions Ca2+ increased the activity of the esterase, while Mg2+, Fe2+, Na+ and Ag+ had different degrees of inhibition, and the inhibitory effect of Ag+ was the most obvious.