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

Abstract

(–)-α-Bisabolol is naturally occurring in many plants and has great potential in health products and pharmaceuticals. 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 (–)-α-bisabolol by metabolic engineering. By introducing the heterologous gene MrBBS and weakening the competitive pathway gene ERG9, a de novo (–)-α-bisabolol biosynthesis strain was constructed that could produce 221.96 mg/L (–)-α-bisabolol. Two key genes for (–)-α-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 (–)-α-bisabolol production. To promote product efflux, overexpression of PDR15 led to an increase in extracellular production. Combined with the optimal strategy, (–)-α-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 (–)-α-bisabolol in yeast.