<br>用于 L-丝氨酸生产的谷氨酸棒杆菌的代谢工程。,Applied and Environmental Microbiology

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用于 L-丝氨酸生产的谷氨酸棒杆菌的代谢工程。
Applied and Environmental Microbiology ( IF 3.9 ) Pub Date : 2005-11-01 , DOI: 10.1128/aem.71.11.7139-7144.2005
Petra Peters-Wendisch ₁ , Michael Stolz , Helga Etterich , Nicole Kennerknecht , Hermann Sahm , Lothar Eggeling

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虽然 L-丝氨酸从糖酵解中间体 3-磷酸甘油酸仅经过三个步骤，并且从葡萄糖同化的碳中多达 8% 是通过 L-丝氨酸形成直接进行的，但之前从葡萄糖生产 L-丝氨酸的菌株的尝试没有成功。我们从功能上鉴定了来自谷氨酸棒杆菌的基因serC和serB，分别编码磷酸丝氨酸转氨酶和磷酸丝氨酸磷酸酶。这些基因的过度表达，与编码L-丝氨酸不敏感的3-磷酸甘油酸脱氢酶的第三个生物合成serA基因serA(delta197)一起，只产生痕量的L-丝氨酸，这些基因在具有L-丝氨酸的菌株中过度表达也是如此。 L-丝氨酸脱水酶基因sdaA被删除。然而，丝氨酸羟甲基转移酶基因 glyA 的表达减少，加上 serA(delta197)、serC 和 serB 的过度表达，导致培养基中短暂积累了高达 16 mM L-丝氨酸。当 sdaA 也被删除时，所得菌株，谷氨酸棒杆菌 delta sdaA::pK18mobglyA'(pEC-T18mob2serA(delta197)CB)，积累了高达 86 mM L-丝氨酸，最大比生产力为 1.2 mmol h(-1)克（干重）（-1）。这说明了谷氨酸棒杆菌野生型中L-丝氨酸的高形成率和利用率。因此，只有通过解决该氨基酸在中央代谢中的明显关键位置，才能实现从葡萄糖生产 L-丝氨酸的代谢工程。

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Metabolic engineering of Corynebacterium glutamicum for L-serine production.

Although L-serine proceeds in just three steps from the glycolytic intermediate 3-phosphoglycerate, and as much as 8% of the carbon assimilated from glucose is directed via L-serine formation, previous attempts to obtain a strain producing L-serine from glucose have not been successful. We functionally identified the genes serC and serB from Corynebacterium glutamicum, coding for phosphoserine aminotransferase and phosphoserine phosphatase, respectively. The overexpression of these genes, together with the third biosynthetic serA gene, serA(delta197), encoding an L-serine-insensitive 3-phosphoglycerate dehydrogenase, yielded only traces of L-serine, as did the overexpression of these genes in a strain with the L-serine dehydratase gene sdaA deleted. However, reduced expression of the serine hydroxymethyltransferase gene glyA, in combination with the overexpression of serA(delta197), serC, and serB, resulted in a transient accumulation of up to 16 mM L-serine in the culture medium. When sdaA was also deleted, the resulting strain, C. glutamicum delta sdaA::pK18mobglyA'(pEC-T18mob2serA(delta197)CB), accumulated up to 86 mM L-serine with a maximal specific productivity of 1.2 mmol h(-1) g (dry weight)(-1). This illustrates a high rate of L-serine formation and also utilization in the C. glutamicum wild type. Therefore, metabolic engineering of L-serine production from glucose can be achieved only by addressing the apparent key position of this amino acid in the central metabolism.

更新日期：2019-11-01

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