QS saponins are a type of triterpenoid glycosides derived from the bark of Quillaja saponaria (Chilean soapbark tree). They are widely used in detergents, food and cosmetics, especially as vaccine adjuvants, due to their cleansing function and immunostimulatory activities. Among these compounds, QS-21 stands out as one of the most potent adjuvants in modern vaccinology due to its remarkable capacity to enhance antigen-specific immunogenicity and elicit robust immune responses. It shows potential for development in both human and veterinary vaccine research. With the rise of synthetic biology technology, the production of QS saponins using microbial cell factories has become a research hotspot. The review systematically summarizes the mechanism of action and practical applications of the most promising QS saponin QS-21, and outlines the biosynthesis pathways of QS saponins, with a focus on exploring the synthetic biology strategies employed for the microbial synthesis of QS saponins. In addition, targeted response strategies have been proposed for the current research challenges. This review aims to lay a theoretical foundation for promoting the medical utilization and sustainable production of QS saponins.
Tian et al. (Tue,) studied this question.