Metabolically engineered plant cell cultures as biofactories for the production of high-value carotenoids astaxanthin and canthaxanthin

Abstract

Abstract Astaxanthin and canthaxanthin are high-value carotenoids with growing demand due to their antioxidant properties and applications in food, cosmetic, and pharmaceutical sectors. However, natural sources are limited and current production methods are often costly or unsustainable. In this study, we developed a plant-based platform for ketocarotenoid biosynthesis using metabolically engineered Nicotiana tabacum BY-2 cell suspension cultures. Specifically, we expressed a marine bacterial crtW gene ( β-carotene ketolase ) alone or in combination with overexpressed plant psy ( phytoene synthase ) and crtI ( phytoene desaturase ) genes. The resulting cell lines displayed visually distinct pigmentation and accumulated different ketocarotenoid profiles based on their genetic modifications. Single-gene transformants expressing crtW produced up to 50 µg g⁻¹ DW of canthaxanthin and 127 µg g⁻¹ DW of astaxanthin. Co-expression of all three genes significantly increased canthaxanthin accumulation to 788 µg g⁻¹ DW. Our results establish suspended undifferentiated plant cells as a scalable and sustainable system for ketocarotenoid production, offering a biological alternative to natural producers and chemical synthesis.