Innovative biorefinery concept for sugar-based ethanol industries: production of protein-rich fungal biomass on vinasse as an aquaculture feed ingredient.

This study examined the potential of producing a protein-rich fungus, Rhizopus microsporus (var. oligosporus), as an aquaculture feed ingredient on vinasse generated during sugar-based ethanol fermentation. Optimization studies showed prolific fungal growth at pH 5.0 and 30 degrees C on vinasse with nutrient (nitrogen and phosphorus) supplementation. The molasses-vinasse resulted in the highest specific fungal biomass yield of 0.21 (g biomass increase/(g initial biomassxg soluble chemical oxygen demand (SCOD) removed)). Organic and inorganic matters were significantly reduced, e.g., 42.02% SCOD and 24.41% total dissolved solids. Thus, the treated effluent could be recycled as process water or used for land applications. The fungal biomass was found to have 45.55% crude protein with significantly high amino acids, arginine and threonine. The integration of innovative fungal technology with sugar-based ethanol production could provide an opportunity for producing food-grade fungal protein for animal feed application with simultaneous water reclamation.