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Dynamics of induced CAT expression in E. coli
Author(s) -
Bentley William E.,
Davis Robert H.,
Kompala Dhinakar S.
Publication year - 1991
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260380709
Subject(s) - inducer , bioprocess , lac operon , escherichia coli , yield (engineering) , protein biosynthesis , cell growth , protein expression , chemistry , biochemistry , protease , microbiology and biotechnology , biology , biophysics , enzyme , gene , materials science , paleontology , metallurgy
The dynamics of chemically induced chloramphenicolaceyl‐transferase (CAT) expression are determined in batch cultures of Escherichia coli DH5αF'IQ [pKK262‐1]. This article is directed towards understanding the coupling of induced cloned‐protein synthesis and reduced cell growth which are balanced in the optimal system. Experimental results indicate that the best inducer (IPTG) concentration is near 1.0 m M when added during midexponential growth. Lower concentrations cause only weak induction, whereas higher concentrations cause sufficiently strong induction that cell growth is suppressed. Induction at the onset of the stationary phase results in high expression but is accompanied by stimulated protease activity. Also, cell mass yield is adversely affected by enhanced protein synthesis. A structured metabolic model is shown to predict the responses of instantaneous growth rate and productivity which result from protein overexpression. This model can be employed to predict alternative reactor strategies and operating conditions necessary for the design of efficient bioprocess.