Jin S, Ye K, Shimizu K
Department of Biochemical Engineering and Science, Kyushu Institute of Technology, Fukuoka, Japan.
J Chem Technol Biotechnol. 1994 Nov;61(3):273-81. doi: 10.1002/jctb.280610316.
In the cultivation of genetically engineered Escherichia coli it is very important to control the substrate concentration at an appropriate level in order to avoid the accumulation of acetate, thereby elevating the expression level of plasmid-encoded protein. In this paper, a pH-stat mode of fuzzy control was considered for the overexpression of beta-galactosidase in the fed-batch cultivation of recombinant E. coli. In the simple pH-stat fuzzy control, the response of pH change in the culture broth to the feeding rate of glucose was used to estimate the glucose consumption rate. In the modified pH-stat fuzzy control, the glucose consumption rate was accurately estimated by using pH change and the change in the carbon dioxide content of the exhaust gas. With this control strategy, the cell density could be increased to 72 g DCW dm-3, which was twofold higher than that attained in the cultivation with the simple pH-stat fuzzy control. The bulk beta-galactosidase concentration was increased to 4150 U cm-3, which was threefold higher than when the simple pH-stat control was used.
在基因工程大肠杆菌的培养过程中，将底物浓度控制在适当水平以避免乙酸盐积累从而提高质粒编码蛋白的表达水平非常重要。本文针对重组大肠杆菌补料分批培养中β-半乳糖苷酶的过量表达，考虑了一种pH值恒控模式的模糊控制方法。在简单的pH值恒控模糊控制中，利用培养液中pH值变化对葡萄糖进料速率的响应来估算葡萄糖消耗速率。在改进的pH值恒控模糊控制中，通过pH值变化和废气中二氧化碳含量的变化来准确估算葡萄糖消耗速率。采用这种控制策略，细胞密度可提高到72 g DCW dm-3，比采用简单pH值恒控模糊控制培养时高出两倍。β-半乳糖苷酶的总体浓度提高到4150 U cm-3，比使用简单pH值恒控时高出三倍。
