Engineering a non-model yeast Rhodotorula mucilaginosa for terpenoids synthesis

Terpenoids have tremendous biological activities and are widely employed in food, healthcare and pharmaceutical industries. Using synthetic biology to product terpenoids from microbial cell factories presents a promising alternative route compared to conventional methods such as chemical synthesis or phytoextraction. The red yeast Rhodotorula mucilaginosa has been widely studied due to its natural production capacity of carotenoid and lipids, indicating a strong endogenous isoprene pathway with readily available metabolic intermediates. This study constructed several engineered strains of R. mucilaginosa with the aim of producing different terpenoids. Monoterpene alpha-terpineol was produced by expressing the alpha-terpineol synthase from Vitis vinifera . The titer of alpha-terpineol was further enhanced to 0.39 mg/L by overexpressing the endogenous ratelimiting gene of the MVA pathway. Overexpression of alpha-farnesene synthase from Malus domestica, in combination with MVA pathway rate -limiting gene resulted in significant increase in alpha-farnesene production, reaching a titer of 822 mg/L. The carotenoid degradation product beta-ionone was produced at a titer of 0.87 mg/L by expressing the beta-ionone synthase from Petunia hybrida . This study demonstrates the potential of R. mucilaginosa as a platform host for the direct biosynthesis of various terpenoids and provides insights for further development of such platforms.