Engineering Saccharomyces cerevisiae for enhanced (-)-α-bisabolol production

(-)-alpha-Bisabolol is naturally occurring in many plants and has great potential in health products and pharma-ceuticals. However, the current extraction method from natural plants is unsustainable and cannot fulfil the increasing requirement. This study aimed to develop a sustainable strategy to enhance the biosynthesis of (-)-alpha-bisabolol by metabolic engineering. By introducing the heterologous gene MrBBS and weakening the competitive pathway gene ERG9, a de novo (-)-alpha-bisabolol biosynthesis strain was constructed that could produce 221.96 mg/L (-)-alpha-bisabolol. Two key genes for (-)-alpha-bisabolol biosynthesis, ERG20 and MrBBS, were fused by a flexible linker (GGGS)3 under the GAL7 promoter control, and the titer was increased by 2.9-fold. Optimization of the mevalonic acid pathway and multi-copy integration further increased (-)-alpha-bisabolol production. To promote product efflux, overexpression of PDR15 led to an increase in extracellular production. Combined with the optimal strategy, (-)-alpha-bisabolol production in a 5 L bioreactor reached 7.02 g/L, which is the highest titer reported in yeast to date. This work provides a reference for the efficient production of (-)-alpha-bisabolol in yeast.