重组大肠杆菌产耐高温β-糖苷酶发酵条件优化

摘要

β-糖苷酶ttβGLY是Thermus thermophilus产生的一种耐高温酶,该酶具有较高的乳糖水解活性和转糖基活性.通过对重组大肠杆菌发酵生产β-糖苷酶ttβGLY条件的研究发现,优化后的培养基组成如下:蛋白胨14 g/L,酵母粉7 g/L,乳清13.3 g/L,NaCl 10 g/L,KH2PO4 3 g/L,K2HPO4 5 g/L,MgSO4·7H2O 1 g/L.种子培养基组成如下:蛋白胨10 g/L,酵母粉5 g/L,葡萄糖4 g/L,NaCl 10 g/L,CaCO3 5 g/L.种龄12 h,接种量8％,装量40 mL/250 mL三角瓶,于37℃发酵24 h,菌体干重10.010 g/L,酶活可达2.384 U/mL,分别是优化前的4.4倍和2.4倍.%ttβGLY is a thermostable β-glucosidase from thermus thermophilus. This β-glucosidase has high activity of hydrolysis and transgalactosylation. The optimized fermentation compositions of genetic engineered Escherichia coli producing thermostable β-glucosidase are as following: medium composition: Peptone 14 g/L,yeast powder 7 g/L, whey 13. 3 g/L, NaCl 10 g/ L, KH2PO4 3 g/L , K2HPO4 5 g/L, MgSO4·7H2O 1 g/L; Seed medium composition: Peptone 10 g/L. yeast powder 5 g/L, glucose 4 g/L, NaCl 10 g/L, CaCO3 5 g/L. Under the condition of inoculom age of 12 h, inoculom volume of 8%, triangular flask with the amount of 250 mL while shaking flask is 40 mL and fermentation time of 24 h at 37℃ , cell dry weight is 10. 010 g/L and enzyme activity is 2. 384 U/mL, showing 4. 4 fold and 2. 4 fold improvement over that of the initial condition.