Abstract
BACKGROUND: Oleaginous microorganisms are promising lipid producers that accumulate an abundance of lipids from different carbon sources. However, the cost of the carbon source in the culture medium is a significant component of the total substrate cost. In this study, lignocellulose from corncob hydrolysate (CBH) was used instead of glucose as a low-cost medium for Schizochytrium fermentation. RESULTS: Eicosapentaenoic acid (EPA) content was 7.31%, after 110 h of fermentation, when the total sugar concentration of CBH was 80 g/L, which was greater than that of pure glucose medium. Replacing 40% of freshwater with fermentation wastewater (FW) resulted in biomass, lipid titer, and EPA titer of 42.16 g/L, 23.05 g/L, and 1.72 g/L, respectively. Compared with the initial CBH medium, the lipid and EPA titers in the 7.5-L bioreactor employing the FW recycling strategy using CBH as a carbon source increased by 12.10% and 9.26%, respectively. CONCLUSIONS: Corncob hydrolysate can be used as a potential low-cost and effective carbon source for EPA production by Schizochytrium sp. The recycling of FW provides a reference for reducing freshwater consumption and environmental pollution and realizing green and economic recycling fermentation.