Nutrients’ Supplementation Impacts On Alcoholic Fermentation of Mixed Wort Containing Corn and Sugarcane

Background: Corn and sugarcane represent the world's most used feedstocks for ethanol production. Despite this, a single fermentation line integrating these both raw materials still require further investigations. Studies suggest that wort's nutrient deficiency or excess influences the yeast metabolism to convert sugar into ethanol. In that regard, this work aims to explore the nutrients’ supplementation impacts on alcoholic fermentation of mixed wort containing 80% v/v corn hydrolyzate and 20% v/v sugarcane syrup. Results: : Corn hydrolyzate and sugarcane syrup presented a carbon/nitrogen ratio above the recommended levels for ethanol production, 229.2 C:N ratio and 322.7 C:N ratio, respectively. As a result, nitrogen was the nutrient with the highest positive impact on yeast specific growth rate (49%), technological yield (35%) and productivity (32%). However, its stoichiometric yield was 5% lower than the wort without supplementation. Finally, organic acids ranged from 0.2-1.4 g.L -1 , glycerol was between 4-8 g.L -1 and mannitol was under 0.05 g.L -1 . All were under the estimated ranges for alcoholic fermentation. Conclusions: : All nutrients supplemented to the mixed wort increased the yeast specific growth rate, except calcium and iron. Moreover, Manganese, Cobalt and potassium impacted positively the stoichiometric yield and Nitrogen was the nutrient with highest technological yield. Finally, further studies should investigate an optimal nitrogen concentration in order to decrease the glycerol and drive the yeast metabolism, preferentially, for ethanol production rather than biomass production.