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A completely automated system for on‐line monitoring of the production of a growth factor secreted during fermentation of Escherichia coli
Author(s) -
Lundström Håkan,
Brobjer Michael,
Österlöf Björn,
Moks Tomas
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.260361011
Subject(s) - fermentation , chromatography , elution , escherichia coli , fusion protein , chemistry , sepharose , fusion , biochemistry , recombinant dna , enzyme , gene , linguistics , philosophy
The production of IGF‐1 (insulin‐like growth factor 1), expressed in Escherichia coli as a secreted fusion protein with affinity for the Fc region of IgG, was monitored automatically during fermentations. A sampling device was used to automatically inject filtered culture medium from the fermentor onto a small affinity column (IgG Sepharose® Fast Flow) connected to a chromatographic system. The area of the eluted peak was proportional to the concentration of the fusion protein. The relationship was linear over the range 25–630 μg/mL with relative standard deviation of around 1% at the higher concentrations. Samples could be monitored automatically every half hour during fermentation (48 h). The method of analysis is nondestructive, allowing further analysis of product quality. A complete evaluation of the monitoring system is described. With this system, fermentations based on the described expression system can be optimized on the basis of product concentration; this will lead to more effective fermentations and higher product yields. It should also be possible to monitor other secreted products with this system by using other affinity gels.