Carotenoids Production by Xanthophyllomyces dendrorhous Mutant Grown on Molasses

Abstract

Astaxanthin, the main carotenoid pigment in dietary red yeast of Xanthophyllomyces dendrorhous, has a huge market potential as fleshy colourant and supplementary food to animal production and health. Cost of carotenoid production would be reduced by using a carotenoid-hyperproducing
mutant and a cheap medium of molasses. Therefore, either mutant yeast [mutant GM807 (derived from gamma irradiation) or mutant n485 (from neutron irradiation)] was selected based on growth and carotenoid production in 5% (v/v) molasses containing 30 g/l urea and 4.5 g/l sodium phosphate under shaking condition for 10 days. The mutant GM807 was superior to mutant n485 in 1.5 fold higher of carotenoid content. Medium formula development for mutant GM807 revealed that beef extract and potassium nitrate enhanced higher carotenoid content than urea did. Concentration of molasses had an effect only on yeast growth but not on carotenoid formation. Total carotenoid content of 450 μg/g of yeast was obtained at the optimum pH of 4. Therefore, molasses (2% v/v) containing 4 g/l potassium nitrate, at pH 4, could possibly be an alternative culture medium for the mutant GM 807 to produce carotenoids.