大肠杆菌ATCC 15224胞内β-半乳糖苷酶生成的动力学研究

A KINETIC STUDY ON THE PRODUCTION OF β-GALACTOSIDASE BY ESCHERICHIA COLI ATCC 15224

本文报道了用补料分批培养方法控制限制生长底物的补料速率,获得一个限制生长底物浓度由10K_s缓慢地渐降的可控培养过程,以保证获得足够数量的准确的(Si,μi),从而得到K_s值。用该法测定了E.coli ATCC 15224在葡萄糖限制生长培养中的K_s值及Monod方程表达式。通过该菌胞内β-坐乳糖苷酶生成与细胞比生长速率相互关系的研究,导出描述该酶生成与培养液中限制生长底物浓度相互关系的曲线方程。它很好地表明了菌体生长的环境因子与胞内酶生成的相互关系及影响,并提示可获得最多胞内酶的培养途径。

A comparison of the fed-batch-culture method with the batch-culture and the continuous culture methods which are used so far to determine the satuation constant of Monod model, K., is made. The fed-batch-culture method used here is better, because by means of fed batch culture one can get the desired cultivation-course where the conc. of growth-limiting substrate in the broth was so slowly decreasing specially from 10 K, to zero of the substrate conc., if controlling the feed rate at some designed values, that the exact and enough points (S_i, μ_i) for the calculation of the K_s of Monod model were gotten. And the K_s of the intracellular β-galactosidase-producing fermentation by E.coli ATCC 15224 growing in the glucose-medium was rationally and exactly determined, using the fed-batch-culture method above. Furthermore, based on the experiments carried out in this study, the mathematical model of the relationship between the activity of β-galactosidase in E.coli ATCC cells and the conc. of the growth-limiting substrate in the broth was derived.