Methods for Inducer Addition in the Production of Interleukin 20 by Escherichia coli

• Main Authors: Chin-Jung Hung, 洪金榮
• Other Authors: Teh-Liang Chen
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/69671158201612445204

碩士 === 國立成功大學 === 化學工程學系碩博士班 === 91 === The common strategy for producing recombinant proteins by Escherichia coli consists increasing cell density at the batch-cultured stage and feeding fresh medium with inducer at the fed-batch stage. For the past years, the effect of feeding strategy for the production of recombinant proteins had been studied extensively. However, the rule for adding inducer (isopropyl-□-D-thiogalactopranoside, IPTG), influences the production of foreign proteins, had never been discussed yet. Accordingly, the objective of this study was to investigate the rule of IPTG addition employing E. coli BL21 (DE3)/pET-43a as the IL-20 producing strain. The proposed rules for the addition of IPTG were according to: (1) constant IPTG concentration, (2) the cell mass at induction, (3) the cell mass at the end of fermentation, and (4) the increase of cell mass after induction. The results first showed that there was no correlation between the amount of IPTG addition and the specific yield of IL-20. In fact, the specific yield of recombinant protein was affected by the amount of IPTG and cell mass. Therefore, the addition of IPTG can not determined by the rules proposed before. However, the data indicated that the specific production rate of IL-20 increased with the increase of IPTG concentration. Besides, the plasmid stability decreased in the first hour after induction as the increase of IPTG concentration. In addition to IPTG, the yield of recombinant protein was affected by other factors. However, it was proposed that the production of IL-20 might continue if both appropriate concentration of IPTG and fresh medium were fed to the fermentation system.