High cell density fermentation of recombinant Escherichia coli expressing human interferon alpha 1.
A defined medium was developed which, by means of a specific fed-batch mode, allows growth of the recombinant Escherichia coli strain TG1 (pBB210) up to a cell density of 60 g dry weight/l. Apart from glucose and aqueous ammonia fed as carbon and nitrogen sources, it was necessary to supply other nutrients or O2-enriched air. Aqueous ammonia also served for pH control. The pO2 level was kept at 20% saturation via closed-loop controls operating the two output variables of stirrer speed and glucose feeding rate. This fed-batch method prevented significant accumulation of acetate and other metabolic by-products. The recombinant E. coli expressed interferon alpha 1 more efficiently at a lower specific growth rate (muPr approximately 0.15 h-1) than at the maximum specific growth rate (mu max = 0.45 h-1). Therefore, fermentation in the batch phase at mu max was only allowed to continue up to a medium cell density. In the succeeding fed-batch phase, the specific growth rate was reduced to muPr by increasing the stirrer speed according to an empirically developed time scale.
Riesenberg
D
D
Zentralinstitut für Mikrobiologie und experimentelle Therapie der AdW der DDR, Jena.
Menzel
K
K
Schulz
V
V
Schumann
K
K
Veith
G
G
Zuber
G
G
Knorre
W A
WA
D000641:Ammonia / Q000378:metabolism; D003470:Culture Media; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005285:Fermentation; D015964:Gene Expression Regulation, Bacterial; D005947:Glucose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007370:Interferon Type I / Q000096:biosynthesis*; D007700:Kinetics; D010101:Oxygen Consumption; D011994:Recombinant Proteins
D003470:Culture Media; D007370:Interferon Type I; D011994:Recombinant Proteins; D000641:Ammonia; D005947:Glucose