Zeaxanthin-Producing Winogradskyella schleiferi Strains

Two pigmented bacteria strains were isolated from the Mediterranean Sea. Phylogenetic analysis revealed that both strains are affiliated with Winograsdskyella schleiferi Z215. However, in contrast to this reference strain, they can assimilate additional carbon sources such as d-mannose, l-arabinose, d-mannitol, and citrate. Zeaxanthin was identified as the major carotenoid produced by both strains, predominantly in the all-trans configuration. Carotenoid biosynthesis kinetics revealed that pigment production commenced at the early stages of growth, with maximal yields reached between 48 and 56 h (between 1 and 1.3 mg L^-1). Specific production yields were 0.7 and 0.9 mg g^-1 for the two strains, respectively. Total carotenoid production was influenced by incubation temperature in both strains. Overall, these findings expand the scientific knowledge on carotenoid-producing marine bacteria and highlight the potential of these newly isolated strains as promising candidates for zeaxanthin biotechnological production for a wide range of novel applications ranging from feed additives to treatments for macular degeneration and melanoma.