Optimization of Medium and Feeding Process for L-Tryptophan Production Fermented by Escherichia coli
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摘要: 为了进一步提高优化大肠杆菌发酵产L-色氨酸的产量,采用响应面法优化了原初始发酵培养基组合成分,建立了乙酸铵-玉米浆补料模式。结果表明优化后培养基组合:0.12%硫酸铵、0.7%磷酸二氢钾、0.15%一水柠檬酸、0.28%七水硫酸镁、0.05%酵母粉、0810 0.39%乙酸铵、0.3%玉米浆。5 L罐的培养验证表明,玉米浆和乙酸铵是影响L-色氨酸产量的主要成分因素,优化后L-色氨酸产量提高了35.4%,发酵结束达到24.53 g/L,单位菌体L-色氨酸产量提高了19.8%,达到0.272 g/OD,糖酸转化率提高了27%,为L-色氨酸发酵提供一定的参考。Abstract: In order to further increase the production of L-tryptophan fermented by Escherichia coli,response surface methodology design were used to optimize the composition of original fermentation medium. Based on the conditions,the feeding mode of ammonium acetate-corn syrup was established. The results showed that the combination of optimized medium were as follows:0.12% ammonium sulfate,0.7% potassium dihydrogen phosphate,0.15% citric acid monohydrate,0.28% magnesium sulfate heptahydrate,0.05% yeast powder 0810,0.39% ammonium acetate,0.3% corn syrup. The validation culture in 5 L tank showed that corn syrup and ammonium acetate were the main factors affecting the production of L-tryptophan. After optimization,the yield of L-tryptophan increased by 35.4%,reaching 24.53 g/L at the end of fermentation. The yield of L-tryptophan in per unit cell increased by 19.8%,reaching 0.272 g/OD. The conversion rate of glucose was increased by 27%.And it would provide some reference for L-tryptophan fermentation.
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Keywords:
- Escherichia coli /
- L-tryptophan /
- fermentation /
- medium optimization /
- feeding process
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