Amplified expression of fructose 1,6-bisphosphatase in Corynebacterium glutamicum increases in vivo flux through the pentose phosphate pathway and lysine production on different carbon sources
Amplified expression of fructose 1,6-bisphosphatase in Corynebacterium glutamicum increases in vivo flux through the pentose phosphate pathway and lysine production on different carbon sources
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DOI：
10.1128/aem.71.12.8587-8596.2005
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发表时间：
2005-12-01
影响因子：
4.4
通讯作者：
Wittmann, C
中科院分区：
文献类型：
--
作者：
Becker, J;Klopprogge, C;Wittmann, C
果糖1，6-二磷酸酶（FBPase）在谷氨酸棒杆菌中的过表达导致对不同糖的赖氨酸产量的显著提高。通过编码延伸因子TU（EFTU）的基因的启动子扩增FBPase的表达使反馈解除调节的赖氨酸生产菌株谷氨酸棒杆菌lysC（fbr）中的赖氨酸产量在葡萄糖上增加40%，在果糖或蔗糖上增加30%。另外，在P（EFTU）fbp突变体中，副产物甘油和二羟基丙酮的形成显著减少。如通过对葡萄糖的C-13代谢通量分析所揭示的，FBPase的过表达导致碳通量从糖酵解重定向到戊糖磷酸途径（PPP），从而导致NADPH供应增加。标准化为100%的葡萄糖摄取通量，C的PPP相对通量为56%。谷氨酸棒杆菌lysC（fbr）P（EFTU）fbp和谷氨酸棒杆菌lysC（fbr）46%。P（EFTU）fbp菌株的NADPH供应通量为180%，而亲本菌株仅为146%。FBPase的扩增通过增加NADPH的供应来增加赖氨酸的产生。与另一个含有sod启动子的突变体的fbp基因上游的比较研究表明，FBPase的表达水平与代谢效应的程度有关。FBPase的过表达似乎可用于使用谷氨酸棒杆菌的基于淀粉和糖蜜的工业赖氨酸生产。流向PPP的通量重定向对于其他NADPH需求化合物的生产以及直接来自PPP的产品也应该是有趣的。
The overexpression of fructose 1,6-bisphosphatase (FBPase) in Corynebacterium glutamicum leads to significant improvement of lysine production on different sugars. Amplified expression of FBPase via the promoter of the gene encoding elongation factor TU (EFTU) increased the lysine yield in the feedback-deregulated lysine-producing strain C glutamicum lysC(fbr) by 40% on glucose and 30% on fructose or sucrose. Additionally formation of the by-products glycerol and dihydroxyacetone was significantly reduced in the P(EFTU)fbp mutant. As revealed by C-13 metabolic flux analysis on glucose the overexpression of FBPase causes a redirection of carbon flux from glycolysis toward the pentose phosphate pathway (PPP) and thus leads to increased NADPH supply. Normalized to an uptake flux of glucose of 100%, the relative flux into the PPP was 56% for C. glutamicum lysC(fbr) P(EFTU)fbp and 46% for C glutamicum lysC(fbr). The flux for NADPH supply was 180% in the P(EFTU)fbp strain and only 146% in the parent strain. Amplification of FBPase increases the production of lysine via an increased supply of NADPH. Comparative studies with another mutant containing the sod promoter upstream of the fbp gene indicate that the expression level of FBPase relates to the extent of the metabolic effects. The overexpression of FBPase seems useful for starch- and molasses-based industrial lysine production with C glutamicum. The redirection of flux toward the PPP should also be interesting for the production of other NADPH-demanding compounds as well as for products directly stemming from the PPP.