Effect of Temperature on the Process of Escherichia coli L-Tryptophan Fermentation

Objective:To study the effect of variable temperature on biomass,L-tryptophan yield,the growth rate and the stability of the plasmid in the process of Escherichia coli TRTH L-tryptophan fed-batch fermentation. Methods:5L-controlled fermentator was used in temperature control in the process of L-tryptophan fed-batch fermentation,to analyses different temperature-related parameters and determine the optimal temperature control strategy. Results:Under the optimized fermentation conditions of 30～36℃ variable temperature control strategy,a final L-tryptophan concentration of 30.19 g / L was obtained after 45 h in 5 liter fermentor,increased by 15.4%; tryptophan synthesis rate increased 21.6%; no loss of plasmid was observed,plasmid copy number remained at a constant level. Conclusion:The temperature is an important impact on the L-tryptophan production.