以粗甘油为原料高产1,3-丙二醇菌株的等离子体复合诱变

Complex Mutation of Klebsiella pneumoniae Producing 1,3-Propanediol from Biodiesel-derived Glycerol

为提高克雷伯氏杆菌(Klebsiella pneumoniae)以粗甘油为底物发酵生产1,3-丙二醇的水平,尝试使用大气压介质阻挡放电等离子体与LiCl进行复合诱变,结合FeCl3和产物耐受的筛选方法,得到一株产量较高的突变菌株KpM30.经批式流加发酵,1,3-丙二醇的产量、摩尔转化率分别达到70.2g/L和0.576,比原始菌株分别提高24.9%和17.7%,乙醇、琥珀酸及乳酸等副产物产量普遍下降,其中乳酸降幅最大,为47.0%.经代谢分析,KpM30在发酵前期ATP及NADH2的生成量为原始菌株的1.6和1.3倍,而在发酵终点1,3-丙二醇支路的碳流量增加了22.6%.KpM30有机酸产量的降低及对粗甘油的良好利用,为降低产物分离难度及实现生物柴油与1,3-丙二醇的联产奠定了基础.

Based on the complex treatment of plasma and LiCl,a mutant strain of Klebsiella pneumoniae was isolated by using the medium containing FeCl3 and selective pressure. The mutant strain named KpM30 improved 1,3-propanediol（1,3-PD） production from biodiesel-derived glycerol through producing less organic acid than the wild strain. The fed-batch fermentation in a 5 L bioreactor showed that the production of 1,3-PD reached 70.2 g/L,its yield on glycerol was 0.576（mol/mol） ,which were increased by 24.9% and 17.7% compared with the wild strain. Meanwhile,the production of lactic acid was decreased by 47.0%. According to the metabolic analysis,the production of ATP and NADH2 by KpM30 were 1.6-fold and 1.3-fold of the wild strain at the beginning of the fermentation. At the end of the fermentation,the carbon flux flowed from glycerol to 1,3-PD was increased by 22.6%. For the less production of organic acid and better use of biodiesel-derived glycerol,this mutated strain was helpful for the separation process after fermentation and the integrated bioprocess combining biodiesel with 1,3-PD production.