响应面法优化生产1,3-丙二醇的克雷伯氏菌突变体发酵条件

摘要

Response surface methodology (RSM) was employed to optimize fermentation parameters for high-level production of 1,3-propanediol(1,3-PD) by the Klebsiella pneumoniae mutant Kp-M2.Based on the Plackett-Burman design,original concentration of glycerol,original pH and seed age were selected as the most critical parameters.The center points of these three parameters were determined using the steepest accent (descent),and all three parameters were then optimized by the Box-Behnken design.A maximum 1,3-PD concentration of 21.6 g/L was predicted by the optimized glycerol concentration (57 g/L),pH (7.3) and seed age (10 h).Using these three optimized parameters,20.7 g/L 1,3-PD was obtained from flask fermentation,which represented a 30％ increase over that obtained under non-optimized conditions.Under batch and fed-batch fermentations using the same optimized parameters,the concentration of 1,3-PD increased to 29.5 and 92.0 g/L,respectively,compared to 19.9 and 76.7 g/L previously obtained for non-optimized fermentation conditions.This showed that RSM could be effectively used to enhance the production of 1,3-PD via fermentation.%为了提高克雷伯氏菌突变体Kp-M2生产1,3-丙二醇的能力,通过响应面法优化该菌株的发酵条件.通过Plackett-Burman方法筛选出影响1,3-丙二醇生物转化的重要发酵条件是初始甘油浓度、初始pH值和接种时间.在经过最陡爬坡实验确定中心点后,上述3个重要参数经Box-Behnken设计进行优化实验.实验结果表明,当甘油质量浓度为57 g/L,pH值为7.3,接种时间为10 h时,1,3-丙二醇的理论最大值为21.6 g/L.摇瓶验证实验1,3-丙二醇质量浓度为20.7 g/L,比未优化条件下的提高30％.在上述优化条件下的间歇发酵和批式流加发酵结果表明,1,3-丙二醇质量浓度分别为29.5和92.0 g/L,均高于对照的19.9和76.7 g/L.上述结果表明,响应面法可以有效地用于优化发酵条件,从而提高1,3-丙二醇产率.