有机酸对产丙二醇菌生长和生产的影响

为提高克雷伯氏肺炎杆菌厌氧发酵生产1,3-丙二醇的能力,在发酵过程中添加有机酸(OA),考察其对菌体生长、1,3-丙二醇及其他副产物合成的影响。实验表明:添加OA可促进菌体生长,加入质量浓度为0.2~0.5g/L的OA,菌体生长的菌液在590 nm处吸光度(OD)值比参照值高出30%;加入过量的OA(>1.0 g/L),则菌体生长受到抑制,OD值比参照值低37%;添加OA可促进单位细胞合成1,3-丙二醇,加入质量浓度为0.2~0.5g/L的OA,单位菌体的1,3-丙二醇质量浓度比参照高3.8%~17.5%;添加OA能提高甘油转化为1,3-丙二醇的转化速率,加入0.2~0.5 g/L的OA,甘油转化为1,3-丙二醇的最大转化速率达0.81 h-1。在15 L罐上批式发酵48 h,1,3-丙二醇最终质量浓度达42.9 g/L,甘油转化为1,3-丙二醇的平均转化率达64%。

Effect of Some Organic Acids on Cell Growth and 1,3-Propanediol Production

To improve 1,3-propanediol production efficiency of Klebsiella pneumoniae,some organic acids(OA) are added in the fermentation process to investigate the effect of these organic acids on cell growth and production of 1,3-propanediol and other by-products.The results show that addition of OA can accelerate the cell growth:adding 0.2～0.5 g/L OA,the biggest optical density(OD) at 590 nm is 30% higher than reference point.But excess OA(>1.0 g/L) will inhibit the growth of cell and the OD is 37% lower than reference point.Addition of OA can increase the production of 1,3-propanediol per cell:adding 0.2～0.5 g/L OA,1,3-propanediol concentration/OD is 3.8%～17.5% higher than reference point.Addition of OA can prompt the molar yield of 1,3-propanediol:adding 0.2～0.5 g/L OA,the maximal molar yield of 1,3-propanediol from glycerol reaches 0.81 h~(-1).When batch fermentation was carried out in 10 L fermentation medium in a 15 L fermenter for 48 h,the final mass concentration of 1,3-propanediol is 42.9 g/L and the average molar yield of 1,3-propanediol from glycerol is 64%.