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Efficient fuzzy control strategies for the application of pH‐stat to fed‐batch cultivation of genetically engineered Escherichia coli
Author(s) -
Jin Sha,
Ye Kaiming,
Shimizu Kazuyuki
Publication year - 1994
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.280610316
Subject(s) - chemistry , stat , escherichia coli , fed batch culture , substrate (aquarium) , biochemistry , biology , gene , fermentation , ecology , stat3
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 β‐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 β‐galactosidase concentration was increased to 4150 U cm −3 , which was threefold higher than when the simple pH‐stat control was used.