Engineering the oleaginous yeast Yarrowia lipolytica for β‐farnesene overproduction

Abstract β‐farnesene is a sesquiterpenoid with various industrial applications which is now commercially produced by a Saccharomyces cerevisiae strain obtained by random mutagenesis and genetic engineering. We rationally designed a genetically defined Yarrowia lipolytica through recovery of L‐leucine biosynthetic route, gene dosage optimization of β‐farnesene synthase and disruption of the competition pathway. The resulting β‐farnesene titer was improved from 8 to 345 mg L‐1. Finally, the strategy for decreasing the lipid accumulation by individually and iteratively knocking out four acyltransferases encoding genes was adopted. The result displayed that β‐farnesene titer in the engineered strain CIBT6304 in which acyltransferases (DGA1 and DGA2) were deleted increased by 45% and reached 539 mg L‐1 (88 mg g‐1 DCW). Using fed‐batch fermentation, CIBT6304 could produce the highest β‐farnesene titer (22.8 g L‐1) among the genetically defined strains. This study will provide the foundation of engineering Y. lipolytica to produce other terpenoids more cost‐efficiently.