Effect of Oxygen Limitation and Medium Composition on Escherichia coli Fermentation in Shake-Flask Cultures

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• 作者：Mario Losen ; Bettina Frö ; lich ; Martina Pohl ; and Jochen Bü ; chs
• 刊名：Biotechnology Progress
• 出版年：2004
• 出版时间：August 2004
• 年：2004
• 卷：20
• 期：4
• 页码：1062 - 1068
• 全文大小：126K
• 年卷期：v.20,no.4(August 2004)
• ISSN：1520-6033

文摘

Shake-flask cultures are widely used for screening of high producing strains. To selectsuitable strains for production scale, cultivation parameters should be applied thatprovide optimal growth conditions. A novel method of measuring respiratory activityin shake-flask cultures was employed to analyze Escherichia coli fermentation underlaboratory conditions. Our results suggest that the length of fermentation, choice ofmedium, and aeration do not normally satisfy the requirements for unlimited growthin shake flasks. Using glycerol rather than glucose as a carbon source greatly reducedthe accumulation of overflow and fermentative metabolites when oxygen supply wasunlimited. A rich buffered medium, Terrific Broth (TB), yielded 5 times more biomasscompared to LB medium but also caused oxygen limitation in standard shake-flaskcultures at shaking frequencies below 400 rpm. These results were used to optimizethe production of benzoylformate decarboxylase from Pseudomonas putida in E. coliSG13009, resulting in a 10-fold increase in volumetric enzyme production. Thisexample demonstrates how variation of medium composition and oxygen supply canbe evaluated by the measurement of the respiratory activity. This can help to efficientlyoptimize screening conditions for E. coli.