Metabolic Engineering of Rhodotorula toruloides for the Production of Linalool

Linalool is widely used in foods, pharmaceuticals, and cosmetics. Microbial production offers a sustainable alternative to current plant extraction and chemical synthesis. In the present study, the oleaginous yeast Rhodotorula toruloides was metabolically engineered for linalool production. Overall, an integrated strategy involving linalool synthase selection, promoter screening, and pathway enhancement was implemented. The linalool biosynthesis baseline was established by using a 51 aa-truncated linalool synthase from Mentha citrate (t51McLIS). The linalool titer was increased to 249.7 mg/L by optimizing the expression of critical enzymes with native promoters. Then, it was improved to 790.2 mg/L by manipulating the mevalonate pathway and further elevated to 845.1 mg/L (42.3 mg/g glucose) by optimizing the fermentation conditions in shake flasks. Finally, the linalool production was enhanced to 2.59 g/L and 26.9 mg/g glucose in a 3 L bioreactor. The results demonstrated the potential of R. toruloides for the microbial production of monoterpenes.