Nutrient recovery from tofu whey wastewater for the economical production of docosahexaenoic acid by Schizochytrium sp. S31

Docosahexaenoic add plays a vital role in human health as it is essential for the proper function of the nervous system and for visual functions. To decrease the cost of docosahexaenoic acid production by Schizochytrium, the cost of the medium should be further decreased. In this study, the use of tofu whey wastewater to culture Schizochytrium sp. for docosahexaenoic add production was tested, with the goal of reducing the medium cost. The results indicated that tofu whey wastewater presented a better culture performance with respect to biomass, lipid, and docosahexaenoic add production compared with three traditional media. Through simple pH adjustment, the biomass and docosahexaenoic add productivity reached 1.89 and 0.24 g/L/day, respectively, which were much higher than those obtained using traditional medium. The removal efficiency of chemical oxygen demand, total nitrogen, and total phosphorus reached 64.7, 66.0, and 59.3%, respectively. Due to the rich nutrients in tofu whey wastewater, the use of extra nitrogen source was avoided and the total medium cost for docosahexaenoic acid production in cultures using tofu whey wastewater was <1/3 of that of traditional media. This result indicated that tofu whey wastewater is an effective and economic basal medium for docosahexaenoic add production by Schizochytrium sp. (C) 2018 Elsevier B.V. All rights reserved.