Effect of gene disruptions of the TCA cycle on production of succinic acid in Saccharomyces cerevisiae
Effect of gene disruptions of the TCA cycle on production of succinic acid in Saccharomyces cerevisiae
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DOI：
10.1016/s1389-1723(99)80004-8
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发表时间：
1999-01-01
影响因子：
2.8
通讯作者：
Okazaki, M
中科院分区：
文献类型：
--
作者：
Arikawa, Y;Kuroyanagi, T;Okazaki, M
琥珀酸盐是日本米酒发酵过程中酵母产生的主要风味成分。使用一系列酿酒酵母菌株，在有氧和厌氧条件下，在高浓度（15%）葡萄糖的存在下，在液体培养中检查导致琥珀酸积累的途径，其中编码TCA循环中所需的酶的表达的各种基因被破坏。当在有氧条件下在含有15%葡萄糖的YPD培养基中培养时，KGD 1（α-酮戊二酸脱氢酶）基因破坏的突变体产生的琥珀酸水平低于野生型菌株，而SDH 1（琥珀酸脱氢酶）基因破坏的突变体产生的琥珀酸水平增加。另一方面，FUM 1（脱氢酶）基因破坏的突变体产生显著更高水平的富马酸，但根本不形成苹果酸。这些结果表明，即使在浓度高达15%的葡萄糖存在下，琥珀酸、富马酸和苹果酸也主要通过TCA循环（氧化方向）合成。当生长条件从好氧转变为厌氧时，不再观察到SDH 1破坏剂中琥珀酸水平的增加，而KGD 1破坏剂中琥珀酸水平的降低仍被观察到。当细胞在葡萄糖缓冲溶液中孵育时，两个延胡索酸还原酶同工酶基因（OSM 1和FRDS）的双突变体显示出与亲本相比50%的琥珀酸生产率。这些结果表明，琥珀酸可以通过两条途径合成，即通过TCA循环的α-酮戊二酸氧化和在厌氧条件下的富马酸还原。和在厌氧条件下的富马酸盐还原。
Succinate is the main taste component produced by yeasts during sake (Japanese rice wine) fermentation. The pathway leading to accumulation of succinate was examined in liquid culture in the presence of a high concentration (15%) of glucose under aerobic and anaerobic conditions using a series of Saccharomyces cerevisiae strains in which various genes that encode the expression of enzymes required in TCA cycle were disrupted. When cultured in YPD medium containing 15% glucose under aerobic conditions, the KGD1 (alpha-ketoglutarate dehydrogenase) gene disrupted mutant produced a lower level of succinate than the wild-type strain, while the SDH1 (succinate dehydrogenase) gene-disrupted mutant produced an increased level of succinate. On the other hand,the FUM1 (fumarase) gene disrupted mutant produced significantly higher levels of fumarate but did not form malate at all. These results indicate that succinate, fumarate and malate are mainly synthesized through the TCA cycle (oxidative direction) even in the presence of glucose at a concentration as high as 15%. When the growth condition was shifted from aerobic to anaerobic, the increased level of succinate in SDH1 disruptants was no longer observed, whereas the decreased level of succinate in the KGD1 diruptant was still observed. A double mutant of the two fumarate reductase isozyme genes (OSM1 and FRDS) showed a succinate productivity of 50% as compared to the parent when cells were incubated in glucose buffered solution. These results indicate that succinate could be synthesized through two pathways, namely, alpha-ketoglutarate oxidation via the TCA cycle and fumarate reduction under anaerobic conditions. and fumarate reduction under anaerobic conditions.