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Modeling the growth and proteinase A production in continuous cultures of recombinant Saccharomyces cerevisiae
Author(s) -
Carlsen Morten,
Jochumsen Kirsten Væver,
Emborg Claus,
Nielsen Jens
Publication year - 1997
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/(sici)1097-0290(19970720)55:2<447::aid-bit22>3.0.co;2-c
Subject(s) - dilution , saccharomyces cerevisiae , oxidative phosphorylation , biochemistry , metabolism , yield (engineering) , overproduction , chemistry , function (biology) , extracellular , biology , yeast , microbiology and biotechnology , gene , thermodynamics , physics
Overexpression of the homologous protein proteinase A (PrA) in Saccharomyces cerevisiae has been achieved by inserting the PrA gene ( PEP4 ) with its own promoter on a 2μ multicopy plasmid. With this system the specific PrA production rate was found to be described well by a linear function of the oxidative glucose metabolism, the reductive glucose metabolism, and the oxidative ethanol metabolism, with a significant lower yield resulting from the reductive glucose metabolism compared with the oxidative glucose metabolism. To describe the experimental data, a simple mathematical model has been set up. The model is based on an assumption of a limited respiratory capacity as suggested by Sonnleitner and Käppeli but extended to describe production of an extracellular protein. The model predicts correctly the critical dilution rate to be between 0.15 and 0.16 h −1 , the decrease in the biomass yield above the critical dilution rate, and the production of proteinase A at different dilution rates. Both the experimental data and model simulations suggest that the optimum operating conditions for protein production is just at the critical dilution rate. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55 : 447–454, 1997.