Unlocking the Potential of Medicago truncatula A17 Cell Suspension Cultures for Bioproduction of Astaxanthin and Canthaxanthin.

Astaxanthin and Canthaxanthin are high-value ketocarotenoids with applications in various sectors, including food and feed industries. Growing demand for healthy diets and changing consumer eating habits have led to an increase in the market size of dietary supplements and functional foods. This increase has a direct impact on the supply of antioxidants and other valuable molecules known for their health benefits. Due to the increasing demand for these pigments, there is a need for new bioproducers. In this study, we present a novel production platform based on metabolically engineered plant-cultured cells. The carotenoid pigments, Astaxanthin and Canthaxanthin, were synthesized using non-photosynthetic Medicago cells in suspension culture. Agrobacterium-mediated transformation was used to introduce a single β-carotene ketolase gene from the marine bacterium Brevundimonas sp. into Medicago cells, generating several stable metabolically engineered lines. HPLC and transcriptomic analyses were performed, showing significant variability in carotenoid content and gene expression, suggesting that intracellular responses influence production levels. The highest-producing line yielded 178.3 μg g DW of Astaxanthin and 37.7 μg g DW of Canthaxanthin. This plant-based platform will contribute to a more sustainable food and feed industry, addressing the growing challenges of global food production and consumption.