Abstract：
Synthetic biology-based engineering of Saccharomyces cerevisiae to produce terpenoid natural products is an effective strategy for their industrial application. Previously, we observed that glycerol addition was beneficial for ginsenoside compound K (CK) production in a S. cerevisiae when it was fermented using the YPD medium. Here, we reconstructed the CK synthesis and glycerol catabolic pathway in a high-yield protopanaxadiol (PPD) S. cerevisiae strain. Remarkably, our engineered strain exhibited the ability to utilize glycerol as the sole carbon source, resulting in a significantly enhanced production of 433.1 ± 8.3 mg L-1 of CK, which was 2.4 times higher compared to that obtained in glucose medium. Transcriptomic analysis revealed that the transcript levels of several key genes involved in the mevalonate (MVA) pathway and the uridine diphosphate glucose (UDPG) synthesis pathway were up-regulated in response to glycerol. The addition of glycerol enhanced CK titers by augmenting the flux of the terpene synthesis pathway and facilitating the production of glycosyl donors. These results suggest that glycerol is a promising carbon source in S. cerevisiae, especially for the production of triterpenoid saponins.
摘要：
基于合成生物学的酿酒酵母工程生产萜类天然产物是其工业应用的有效策略。以前,我们观察到，当使用YPD培养基发酵时，甘油的添加对酿酒酵母中人参皂苷化合物K（CK）的产生是有益的。这里,我们在高产原人参二醇（PPD）酿酒酵母菌株中重建了CK合成和甘油分解代谢途径。值得注意的是,我们的工程菌株表现出利用甘油作为唯一碳源的能力，导致CK的产量显着提高了433.1±8.3mgL-1，比在葡萄糖培养基中获得的高2.4倍。转录组学分析显示,参与甲羟戊酸(MVA)途径和尿苷二磷酸葡萄糖(UDPG)合成途径的几个关键基因的转录水平响应于甘油而上调。甘油的添加通过增加萜烯合成途径的通量和促进糖基供体的产生来提高CK滴度。这些结果表明，甘油是酿酒酵母中一种有前途的碳源，特别是三萜皂苷的生产。
