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Effect of cell growth rate on the performance of a two‐stage continuous culture system in a recombinant Escherichia coli fermentation
Author(s) -
Park Sunghoon,
Ryu Dewey D. Y.,
Kim Jeong Yoon
Publication year - 1990
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.260360509
Subject(s) - plasmid , fermentation , escherichia coli , recombinant dna , growth rate , biology , microbiology and biotechnology , gene , gene expression , chemistry , biochemistry , mathematics , geometry
As part of the process optimization of a two‐stage continuous culture system, the effect of growth rate μ 2 appon the performance of the second stage (production stage) was studied in a recombinant Escherichia coli K12 (ΔH1Δ trp /pPLc23 trpA1 ). Important parameters considered were specific gene expression rate, plasmid content, and plasmid stability, all of which were closely related to the cell growth rate and the production rate of the cloned gene product ( trp α). When operating conditions were maintained constant ( T 1 = 35°C, D 1 = 0.9 h −1 , T 2 = 40°C, and D 2 = 0.7 h −1 ) and μ 2 appwas varied, plasmid content in the second stage showed its maximum at μ 2 app= 0.4 h −1 and decreased thereafter. Specific gene expression rate linearly increased with increasing μ 2 app , while plasmid stability decreased. Optimum cell growth rate giving the maximum value in overall productivity was observed at around μ 2 app= 0.4 h −1 . The contribution or role of the three parameters, specific gene expression rate, plasmid content, and plasmid stability in exhibiting the maximum productivity at the optimal μ 2 appis discussed.