Efficient and environmentally friendly method for carotenoid extraction from Paracoccus carotinifaciens utilizing naturally occurring Z-isomerization-accelerating catalysts

This study aimed to improve the efficiency of Paracoccus carotinifaciens-derived carotenoid (astaxanthin, adonirubin, adonixanthin) extraction using environmentally friendly Z-isomerization-accelerating catalysts. Adding naturally occurring catalysts such as isothiocyanates and polysulfides to the extraction solvent significantly improved the efficiency of carotenoid extraction, likely because of enhanced solubility of carotenoid Z-isomers compared with all-E-isomers. Indeed, addition of the catalysts markedly increased the content of carotenoid Z-isomers in the resulting extract. The use of a catalyst ally! isothiocyanate, which is abundantly included in Brassicaceae plant family, at high extraction temperature and long extraction time led to increased carotenoid recovery and Z-isomer content. These findings will enhance the efficiency of organic solvent-based extraction of carotenoids from carotenoid-rich sources. Numerous studies have reported that the Z-isomers of carotenoids exhibit greater bioavailability and antioxidant capacity than the all-E-isomers. Hence, the method proposed here utilizing Z-isomerization-accelerating catalysts could enhance both the extraction efficiency and beneficial health effects of carotenoids.