Elimination of by-product formation during production of 1,3-propanediol in Klebsiella pneumoniae by inactivation of glycerol oxidative pathway
Elimination of by-product formation during production of 1,3-propanediol in Klebsiella pneumoniae by inactivation of glycerol oxidative pathway
复制标题
DOI：
10.1007/s00253-009-1980-1
复制
发表时间：
2009-09-01
影响因子：
5
通讯作者：
Kim, Chul Ho
中科院分区：
文献类型：
--
作者：
Seo, Mi-Young;Seo, Jeong-Woo;Kim, Chul Ho
由肺炎克雷伯氏菌（Klebsiella pneumoniae）微生物生产1，3-丙二醇（1，3-PD）涉及通过氧化途径合成的各种副产物的形成。为了消除副产物的合成，通过构建两株突变株来失活甘油代谢的氧化分支。在一个突变株中，编码甘油脱氢酶和二羟丙酮激酶的结构基因从染色体DNA中缺失，而在第二个突变株达尔中，其是一种推定的激活转录因子，基因表达从染色体DNA中缺失。在缺失编码1，3-PD氧化还原酶的dhaT基因的所得突变株中，其在用lacZ启动子替换天然启动子的同时被缺失，消除了除乙酸之外的副产物形成，但其仍以较低水平产生1，3-PD，这可能是由于推定的催化1，3-PD产生的氧化还原酶。还原途径恢复的重组菌株产生的1，3-PD量略低于亲本菌株，这可能是由于启动子的取代导致DhaB活性降低。然而，重组菌株的产率（0.57 mol mol（-1））高于野生型Cu菌株（0.47 mol mol（-1））。
The microbial production of 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae involves the formation of various by-products, which are synthesized through the oxidative pathway. To eliminate the by-products synthesis, the oxidative branch of glycerol metabolism was inactivated by constructing two mutant strains. In one of the mutant strains, the structural genes encoding glycerol dehydrogenase and dihydroxyacetone kinase were deleted from the chromosomal DNA, whereas in the second mutant strain dhaR, which is a putative transcription factor that activates, gene expression was deleted from the chromosomal DNA. In the resultant mutant strains lacking the dhaT gene encoding 1,3-PD oxidoreductase, which was simultaneously deleted while replacing the native promoter with the lacZ promoter, the by-product formation except for acetate was eliminated, but it still produced 1,3-PD at a lower level, which might be due to a putative oxidoreductase that catalyzes the production of 1,3-PD. The recombinant strains in which the reductive pathway was recovered produced slightly lower amount of 1,3-PD as compared to the parent strain, which might be due to the reduced activity of DhaB caused by the substitution of the promoter. However, the production yield was higher in the recombinant strain (0.57 mol mol(-1)) than the wild type Cu strain (0.47 mol mol(-1)).