Turning the non-pathogenic yeast Starmerella bombicola into a powerful long-chain dicarboxylic acid production host.

Bio-based long-chain dicarboxylic acids (LCDAs) are in high demand in the polymer industry. These compounds have diverse applications as building blocks for polymers with distinct features, which lead to a fast-growing global LCDA market. However, bio-based LCDA production is currently limited in Europe as established processes are using the pathogenic yeast, Candida tropicalis. Therefore, this study aimed to establish safe and sustainable LCDA production using an industrially relevant non-pathogenic yeast, Starmerella bombicola. The metabolic network was successfully controlled to channel fatty acids from rapeseed oil into the ω-oxidation for the high production of LCDAs. Importantly, the engineered yeast strain produced 5.5 g/l of total LCDAs in shake flasks. Furthermore, pH optimization of the bioprocess resulted in a significant improvement of the total LCDA titer up to 117.8 g/l. The outcomes strongly demonstrate that S. bombicola can serve as a safe and efficient platform microorganism for industrial LCDA production.