Valorization of sugar-to-ethanol process waste vinasse: A novel biorefinery approach using edible ascomycetes filamentous fungi.

The aim of the present work was to study the integration of edible ascomycetes filamentous fungi into the existing sugar- or molasses-to-ethanol processes, to grow on vinasse or stillage and produce ethanol and protein-rich fungal biomass. Two fungal strains, Neurospora intermedia and Aspergillus oryzae were examined in shake flasks and airlift-bioreactors, resulting in reduction of vinasse COD by 34% and viscosity by 21%. Utilization of glycerol and sugars were observed, yielding 202.4 or 222.8g dry fungal biomass of N. intermedia or A. oryzae respectively, per liter of vinasse. Integration of the current process at an existing ethanol facility producing about 100,000m of ethanol per year could produce around 200,000-250,000tons of dry fungal biomass (40-45% protein) together with about 8800-12,600m extra ethanol (8.8-12.6% of production-rate improvement).