Framework for online optimization of recombinant protein expression in high-cell-density Escherichia coli cultures using GFP-fusion monitoring

• Published in: Biotechnology and bioengineering 2000-08, Vol.69 (3), p.275-285
• Main Authors: Chae, Hee Jeong, Delisa, Matthew P., Cha, Hyung Joon, Weigand, William A., Rao, Govind, Bentley, William E.
• Format: Article
• Language: English
• Subjects: Algorithms; Arabinose - pharmacology; Biological and medical sciences; Biomass; Biotechnology; Cell Division - drug effects; chloramphenicol acetyltransferase; Chloramphenicol O-Acetyltransferase - biosynthesis; Chloramphenicol O-Acetyltransferase - genetics; Chloramphenicol O-Acetyltransferase - metabolism; Cloning; Computer Simulation; Enzymes; Escherichia coli; Escherichia coli - cytology; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - metabolism; Feedback; Fluorescent Dyes - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial - drug effects; Genes, Reporter - genetics; Glucose - metabolism; green fluorescent protein; Green Fluorescent Proteins; high-cell-density cultivation; Isopropyl Thiogalactoside - pharmacology; Kinetics; Luminescent Proteins - biosynthesis; Luminescent Proteins - genetics; Luminescent Proteins - metabolism; mathematical model; Mathematical models; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Models, Biological; Monitoring; online optimization; Online systems; Optimization; Proteins; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/1097-0290(20000805)69:3<275::AID-BIT5>3.0.CO;2-Y

A framework for the online optimization of protein induction using green fluorescent protein (GFP)‐monitoring technology was developed for high‐cell‐density cultivation of Escherichia coli. A simple and unstructured mathematical model was developed that described well the dynamics of cloned chloramphenicol acetyltransferase (CAT) production in E. coli JM105 was developed. A sequential quadratic programming (SQP) optimization algorithm was used to estimate model parameter values and to solve optimal open‐loop control problems for piecewise control of inducer feed rates that maximize productivity. The optimal inducer feeding profile for an arabinose induction system was different from that of an isopropyl‐β‐D‐thiogalactopyranoside (IPTG) induction system. Also, model‐based online parameter estimation and online optimization algorithms were developed to determine optimal inducer feeding rates for eventual use of a feedback signal from a GFP fluorescence probe (direct product monitoring with 95‐minute time delay). Because the numerical algorithms required minimal processing time, the potential for product‐based and model‐based online optimal control methodology can be realized. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 69: 275–285, 2000.