Co-utilization of corncob hydrolysate and fermentation wastewater for eicosapentaenoic acid production by Schizochytrium sp.

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.