Utilization of seawater and wastewater from shrimp production in the fermentation of papaya residues to ethanol

Abstract Seawater (SW) and wastewater from shrimp production (WSP) were used as a solvent for the fermentation of papaya residues (Carica papaya) by Wickerhamomyces sp. UFFS-CE-3.1.2 and Saccharomyces cerevisiae CAT-1. For comparative purposes and evaluation of the effect of salinity, ultrapure water (UW) was used as control. Fermentative parameters were evaluated in Plackett-Burman planning to assess ethanol production's significant variables. Urea supplementation was the only variable not significant for the proposed process, suggesting that papaya residues contain all the nutrients needed for fermentation. The experiments conducted with the different water sources resulted in similar concentrations of ethanol. Maximum ethanol concentration was obtained after nine h of fermentation using Wickerhamomyces sp. UFFS-CE-3.1.2 (27.31±1.40 g L-1) and 12 h using S. cerevisiae CAT-1 (24.53±0.68 g L-1). This study demonstrated that SW and WSP could replace freshwater without affecting ethanol production. Papaya residues from the fruit and vegetable sectors can be considered a promising substrate source for ethanol production.