Metabolic Engineering of Saccharomyces cerevisiae for Production of Canthaxanthin, Zeaxanthin, and Astaxanthin

Abstract

The sustainable production of natural compounds is increasingly important in today's industrial landscape. This study investigates the metabolic engineering of <i>Saccharomyces cerevisiae</i> for the efficient biosynthesis of valuable carotenoids: canthaxanthin, zeaxanthin, and astaxanthin. Utilizing a tailored parental yeast strain, Sp_Bc, we optimized the carotenoid pathway by screening and identifying CrtW and CrtZ enzymatic variants. The CrtW variant from <i>Bradyrhizobium</i> sp. achieved a canthaxanthin titer of 425.1 ± 69.1 µg/L, while the CrtZ variant from <i>Pantoea ananatis</i> achieved a zeaxanthin titer of 70.5 ± 10.8 µg/L. Additionally, we optimized carotenoid production by exploring enzyme fusion strategies for all three studied carotenoids and organelle compartmentalization specifically for enhancing astaxanthin synthesis. We further improved carotenoid production by integrating the optimal gene constructs into the yeast genome and deleting the <i>GAL80</i> gene, enabling the use of sucrose as a carbon source. The engineered strain Sp_Bc-Can001 <i>∆gal80</i> was evaluated in a 5 L bioreactor fermentation, achieving a notable canthaxanthin titer of 60.36 ± 1.51 mg/L using sucrose. This research conclusively establishes <i>S. cerevisiae</i> as a viable platform for efficient carotenoid biosynthesis and, for the first time in this yeast system, illustrates sucrose's viability as a carbon source for canthaxanthin production. These findings pave the way for sustainable, cost-effective carotenoid production at an industrial scale.