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Production of Fusion Protein SpA:: Eco RI in Batch Culture in a 60‐L Airlift Tower Loop Reactor
Author(s) -
Brandes Lutz,
Wu Xiaoan,
Maschke Hans E.,
Jürgens Heike,
Reinhardt Birgit,
Schügerl Karl
Publication year - 1993
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp00020a002
Subject(s) - chemistry , aeration , chromatography , biochemistry , airlift , bioreactor , ammonia , continuous stirred tank reactor , respiratory quotient , food science , organic chemistry
Escherichia coli JM103 carrying the expression plasmid pMTC48, repressor plasmid pRK248, and protection plasmid pEcoR4 was grown in a 60‐L working volume airlift tower loop reactor on M9 minimal medium. Production of fusion protein SpA:: Eco RI was induced by a temperature shift from 30 to 38 (optimum), 40, or 42°C. The following parameters were monitored: cell mass concentration (X), total cell counts (TCC), number of colony‐forming units (CFU), concentrations of glucose, acetate, ethanol, pyruvate, lactate, succinate, amino acids, and ammonia, and soluble and total protein content, as well as product concentration (enzyme activity of the fusion protein), dissolved oxygen concentration, oxygen utilization rate (OUR), CO 2 production rate (CPR), respiration quotient (RQ), and volumetric mass‐transfer coefficients (k L a). Product formation by temperature shift was only observed if LB concentrate was added to the culture at the same time the aeration rate was increased to avoid oxygen‐transfer limitation. No product accumulation was observed with glucose and ammonia supplementation. During gene expression, X and TCC increased, CFU decreased, acetate increased, and the primary metabolite (ethanol, pyruvate, lactate) concentrations as well as OUR and CPR passed a maximum while RQ changed only slightly. These facts indicate that, during gene expression, the metabolic activity of the cell passes a maximum, and after that it decreases. With increasing aeration rate, the volumetric productivity increased, but the specific productivity with respect to the cell concentration decreased.