BACKGROUND Ginsenoside compound K (CK), one of the primary active metabolites of protopanaxadiol-type ginsenosides, is produced by the intestinal flora that degrade ginseng saponins and exhibits diverse biological properties such as anticancer, anti-inflammatory, and anti-allergic properties. However, it is less abundant in plants. Therefore, enabling its commercialization by construction of a Saccharomyces cerevisiae cell factory is of considerable significance. RESULTS We induced overexpression of PGM2, UGP1, and UGT1 genes in WLT-MVA5, and obtained a strain that produces ginsenoside CK. The production of CK at 96 h was 263.94 ± 2.36 mg/L, and the conversion rate from protopanaxadiol (PPD) to ginsenoside CK was 64.23 ± 0.41%. Additionally, it was observed that the addition of glycerol was beneficial to the synthesis of CK. When 20% glucose (C mol) in the YPD medium was replaced by the same C mol glycerol, CK production increased to 384.52 ± 15.23 mg/L, which was 45.68% higher than that in YPD medium, and the PPD conversion rate increased to 77.37 ± 3.37% as well. As we previously observed that ethanol is beneficial to the production of PPD, ethanol and glycerol were fed simultaneously in the 5-L bioreactor fed fermentation, and the CK levels reached 1.70 ± 0.16 g/L. CONCLUSIONS In this study, we constructed an S. cerevisiae cell factory that efficiently produced ginsenoside CK. Glycerol effectively increased the glycosylation efficiency of PPD to ginsenoside CK, guiding higher carbon flow to the synthesis of ginsenosides and effectively improving CK production. CK production attained in a 5-L bioreactor was 1.7 g/L after simultaneous feeding of glycerol and ethanol.

中文翻译：

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甘油促进酿酒酵母中化合物 K 的产生。


背景人参皂苷化合物K（CK）是原人参二醇型人参皂苷的主要活性代谢物之一，由肠道菌群降解人参皂苷产生，具有抗癌、抗炎、抗过敏等多种生物学特性。然而，它在植物中含量较少。因此，通过建设酿酒酵母细胞工厂实现其商业化具有重要意义。结果我们在WLT-MVA5中诱导PGM2、UGP1和UGT1基因的过度表达，并获得产生人参皂苷CK的菌株。 96 h时CK产量为263.94±2.36 mg/L，原人参二醇(PPD)向人参皂苷CK的转化率为64.23±0.41%。此外，还观察到甘油的添加有利于CK的合成。当YPD培养基中20%葡萄糖（C mol）替换为相同C mol甘油时，CK产量增加至384.52±15.23 mg/L，比YPD培养基高45.68%，PPD转化率增加至77.37 ± 3.37% 也是如此。正如我们之前观察到的，乙醇有利于PPD的产生，在5L生物反应器补料发酵中同时补料乙醇和甘油，CK水平达到1.70±0.16g/L。结论在这项研究中，我们构建了一个高效生产人参皂苷CK的酿酒酵母细胞工厂。甘油有效提高了PPD对人参皂苷CK的糖基化效率，引导更高的碳流进行人参皂苷的合成，有效提高CK产量。同时加入甘油和乙醇后，5 L 生物反应器中获得的 CK 产量为 1.7 g/L。