Biosynthesis of pyruvic acid from glucose by Blastobotrys adeninivorans
Biosynthesis of pyruvic acid from glucose by Blastobotrys adeninivorans
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DOI：
10.1007/s00253-016-7618-1
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发表时间：
2016-09-01
影响因子：
5
通讯作者：
Morgunov, Igor G.
中科院分区：
文献类型：
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作者：
Kamzolova, Svetlana V.;Morgunov, Igor G.
研究了不同酵母从葡萄糖合成丙酮酸（PA）的能力。研究表明，在硫胺素限制生长的条件下，许多酵母能够从葡萄糖中产生PA。这种能力是首次在酵母腺细胞中发现的。这种酵母中PA的产生（过度合成）可以用硫胺素依赖性丙酮酸脱氢酶的功能紊乱来解释。也就是说，这种酶的部分抑制导致PA从酵母细胞中排泄出来。由于丙酮酸脱氢酶的不完全抑制，乙酰辅酶a的形成继续进行，尽管水平较低，维持了三羧酸（TCA）循环中α -酮戊二酸（KGA）的合成。KGA在TCA循环中不再被氧化，因为硫胺素限制抑制α -酮戊二酸脱氢酶。因此，KGA作为PA过度合成的副产物从酵母细胞中排出。此外，酵母细胞中KGA水平的增加抑制了TCA循环中nad依赖的异柠檬酸脱氢酶，并增加了柠檬酸的产生和排泄，柠檬酸是PA过度合成的另一副产物。在发酵罐培养过程中，菌株Blastobotrys adeninivorans VKM Y-2677从葡萄糖中产生43.2 gl (-1) PA，产物产量（Y-PA）为0.77 g PA/g葡萄糖。KGA的PA与副产物的比例为18:1，柠檬酸为8:1。
The ability of taxonomically different yeasts to synthesize pyruvic acid (PA) from glucose was studied. The study showed that many yeasts are able to produce PA from glucose under the condition of growth limitation by thiamine. This ability was found in the yeast Blastobotrys adeninivorans for the first time. The production (oversynthesis) of PA in this yeast can be explained by disturbance in the function of thiamine-dependent pyruvate dehydrogenase. Namely, the partial inhibition of this enzyme brings about the excretion of PA from the yeast cells. Due to incomplete inhibition of pyruvate dehydrogenase, the formation of acetyl-CoA continues, although at a lower level, maintaining the synthesis of alpha-ketoglutaric acid (KGA) in the tricarboxylic acid (TCA) cycle. KGA is no longer oxidized in the TCA cycle, because thiamine limitation inhibits alpha-ketoglutarate dehydrogenase. As a result, KGA is excreted from the yeast cells as a byproduct of PA oversynthesis. Furthermore, the increased level of KGA in the yeast cells inhibits NAD-dependent isocitrate dehydrogenase in the TCA cycle and enhances the production and excretion of citric acid, another byproduct of PA oversynthesis. During cultivation in a fermentor, the strain Blastobotrys adeninivorans VKM Y-2677 produced 43.2 g l(-1) PA from glucose with a product yield (Y-PA) of 0.77 g PA/g glucose. The proportion of PA to byproducts was 18:1 for KGA and 8:1 for citric acid.