Combined utilization of agro-industrial wastewaters for non-lignocellulosic second-generation bioethanol production

COMELLI, RN; SELUY, LG; BENZZO, MT; ISLA, MA

Waste and Biomass Valorization

Springer Netherlands

Año: 2020

1877-2641

Bioethanol is one of the most important renewable fuels, and its production from biomass isa potential substitute for fossil fuels. Second-generation technologies cover awide range of biomass resources, from agriculture to forestry and wastematerials. Although lignocellulosic residues represent an attractive feedstockfor ethanol production, their processing is not economical due to problems arisingfrom the recalcitrant nature of the biomass and the need for pretreatment. Themain purpose of this work was to evaluate the feasibility of the direct use ofthree agro-industrial wastes as low-cost feedstock for ethanol production:wastewaters of the sugar-sweetened beverage industry as carbon source, purgesof fermentation tanks of the brewery industry as inoculum and corn steep waterfrom the corn starch processing industry as nitrogen source. Fermentations wereperformed in batch mode under anaerobic conditions, and the concentrations ofsugar, biomass and ethanol were monitored over time. The process was optimized usingsurface-response methodology. Spent brewer?s yeast and corn steep watersupplementation at ratios of 12.4% v/v and 8.4% v/v, respectively, were optimalfor ethanol production. In these conditions, the sugar available in the soft-drinkwastewater was completely depleted in less than 8 h, with an average ethanolyield of 0.45 gethanol/gsugar. The process developedcould become an alternative bioprocess for production of non-lignocellulosicbioethanol