Flexixanthin: A next-generation rare microbial carotenoid for food applications

Flexixanthin is a rare monocyclic xanthophyll carotenoid characterized by its distinctive orange-red color and promising bioactive properties, including antioxidant, anti-microbial, and anti-inflammatory activities. It is mainly produced by marine bacteria of the Flexibacter and Algoriphagus genera. Unlike common cyclic carotenoids, flexixanthin follows a unique biosynthetic route, which contributes to its structural and functional singularity. This review provides a focused overview of microbial-derived flexixanthin, highlighting its biosynthesis, biological activities, and potential applications in the food sectors. Emphasis is placed on the advantages of microbial production in terms of sustainability and scalability, alongside an evaluation of the current limitations related to industrial production, stability, and encapsulation technologies. Flexixanthin stands out as a nextgeneration carotenoid with notable functional properties. Its microbial origin and monocyclic structure open up new possibilities for innovation in functional foods. Despite these promising attributes, further research is needed to improve its production efficiency, formulation stability, and regulatory approval for commercial applications. Identifying and addressing these challenges could position flexixanthin as a competitive and valuable natural pigment in the carotenoid market.