1,3-丙二醇发酵过程中底物抑制及其对策的研究

研究了底物甘油浓度对Klebsiellapneumoniae发酵生产 1 ,3 丙二醇的影响 ,并通过实验确定了最佳的初始甘油浓度和甘油开始对产物生成产生抑制作用的浓度。针对底物抑制现象 ,提出了菌种驯化和流加甘油发酵两种解决途径。结果表明 :采用原始菌株发酵 ,适宜的甘油初始浓度为 642 .4mmol/L ,此时 1 ,3 丙二醇浓度和转化率分别可达 2 60mmol/L和 0 .492mol/mol;在较高甘油初始浓度 (789mmol/L)的情况下 ,经驯化培养获得的耐底物抑制菌株 ,可将最终 1 ,3 丙二醇浓度和转化率分别提高到 30 0 .9mmol/L和 0 .530mol/mol;采用流加甘油发酵工艺 ,1 ,3 丙二醇浓度和转化率分别可提高到 397.7mmol/L和 0 .62 5mol/mol。

Substrate inhibition in fermentation of 1,3-propanediol and countermeasures to it

Inhibiting effects of initial glycerol concentration on fermentation production of 1,3 propanediol by using Klebsiella pneumoniae was studied.Inhibiting effects of glycerol on cell growth and product formation was discussed and optimal initial glycerol concentration was determined.Both approaches of bacteria improvement and fed batch fermentation to avoid substrate inhibition were proposed.With original Kp,appropriate initial glycerol concentration,642.4 mmol/L was obtained,correspondingly,the maximal 1,3 PDO concentration and yield,260 mmol/L and 0.492 mol/mol,were reached respectively.With substrate tolerant mutants,1,3 PDO concentration and yield could be increased more,which were 300.9 mmol/L and 0.530 mol/mol respectively.Fed batch fermentation can also increase 1,3 PDO concentration and yield,accompanying the maximal 1,3 PDO concentration and yield,397.7 mmol/L and 0.625 mol/mol is got respectively.