应用响应面法优化发酵培养基提高达托霉素产量

Medium optimization with the response surface methodology to improve daptomycin production

摘要:

【背景】达托霉素来自玫瑰孢链霉菌NRRL 11379的发酵产物，是重要的临床用抗生素。其原始产生菌发酵周期长，影响达托霉素的生产效率。本实验室前期在天蓝色链霉菌中重构了达托霉素的生物合成途径，有效地缩短了发酵周期，但重组菌株K10中达托霉素发酵产量很低，制约了后续的研究和开发。【目的】利用响应面法优化产达托霉素的重组菌天蓝色链霉菌K10的发酵培养基组分，获得达托霉素高产的发酵培养基配方。【方法】采用单因素实验、Plackett-Burman试验、最陡爬坡试验和响应面法设计优化达托霉素发酵培养基，使用Design Expert 8.0对实验数据进行分析。【结果】培养基各成分中影响达托霉素产量的3个主要因素是糊精、酵母提取物和酪蛋白，其最佳浓度分别为25.11、2.20和2.00 g/L。在此条件下，达托霉素产量达到15.30 mg/L，较原始培养基产量提高了2.17倍。【结论】实验获得了达托霉素产量明显提高的天蓝色链霉菌K10发酵培养基配方，为达托霉素的后续研究提供可靠支撑。

Abstract:

[Background] Daptomycin is an important antibiotic isolated from Streptomyces roseospoous NRRL 11379 and is clinically used to treat infections. The long fermentation period of the daptomycin producer restricts its productivity. Hence, a daptomycin heterologous expression strain Streptomyces coelicolor K10 that can significantly shorten the fermentation period, was constructed in our previous work. Unfortunately, the very low titer of daptomycin in S. coelicolor K10 hampers its use in further studies. [Objective] The fermentation medium of S. coelicolor K10 was optimized by response surface methodology to improve daptomycin production. [Methods] Plackett-Burman experiment, the steepest ascent method, and response surface methodology were used to optimize the fermentation medium of S. coelicolor K10; and the experiment data were analyzed using Design Expert 8.0. [Results] The main influential factors were dextrin, yeast extract, and casein; and their optimal concentrations were 25.11, 2.20, and 2.00 g/L, respectively. Under the optimal condition, the production of daptomycin could reach 15.30 mg/L, about 2.17 times higher than that in the original medium. [Conclusion] This study increases the daptomycin titer of S. coelicolor K10 considerably and provides a reliable basis for the follow-up studies of daptomycin.