Enhanced bioaccumulation of astaxanthin in Phaffia rhodozyma by utilising low-cost agro products as fermentation substrate

Low-cost medium component for fermentation and the down-streaming process for intracellular astaxanthin production by Phaffia rhodozyma MTCC 7536 were optimized using statistical methods. From a total of fifteen, four important natural media components were screened based on biomass, total carotenoids and astaxanthin production. The statistical model was constructed via Box–Behnken design using selected medium parameters (Calendula officinalis flower, Zea mays seed flour, Triticum aestivum seed flour, Pennisetum glaucum seed flour). Under optimized condition, C. officinalis (dried and crushed marigold flower) 2.5 g l−1, Z. mays (corn flour) 2.38 g l−1, T. aestivum (wheat flour) 1.89 g l−1 and P. glaucum (pearl millet flour) 2.47 g l−1, astaxanthin production was 1448.38 μg g−1 (dry cell weight) with volumetric yield of 1333.96 μg ml−1 (R2=0.908, p-value<0.0001 and validly=94.9%). A successful and significant improvement (12-fold) in the production of intracellular free astaxanthin by the P. rhodozyma was achieved by adding low-value agro products in fermentation medium, which may result in a significant reduction in the cost of fermentation process.

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