Avaliação da produção de bioetanol a partir do caldo obtido de uma mistura de resíduos de frutas utilizando a levedura Wickerhamomyces sp. UFFS-CE-3.1.2

Abstract

The use of fruit residues from domestic consumption for bioethanol production is an innovative perspective that guarantees low-cost biomass, generated in large quantities, that have sugars readily available in their composition and do not require complexes processes of pretreatment and hydrolysis, resembling first-generation bioethanol production systems. In this study, the ideal conditions for sugar extraction were determined using a Central Rotational Composite Design (CRCD) 22 , evaluating the temperature and the solid/liquid ratio (S:L) effects on the process. The juice extracted by the optimized conditions was used as a fermentation medium for the bioethanol production using the yeast Wickerhamomyces sp. UFFS-CE-3.1.2. The supplementation influence of the juice extracted from the fruit residue mixture was also investigated with two different nitrogen sources (yeast extract and urea) in the bioethanol production. Furthermore, a preliminary study of alcoholic fermentation in a bioreactor was developed to identify the possibility of scaling up. The ideal condition for sugars extraction was determined using 12% (wdried v -1 ) of a fruit residue mixture and mechanical stirring at 100 rpm and 25 ° C for 5 minutes, resulting from experimental planning analysis also considering the juice volume obtained after filtration. Fermentation without nitrogen source addition resulted in a bioethanol production of 23.18 ± 0.47 g L-1 in just 9 hours of the fermentation process. Although the juice fruit residues supplementation with yeast extract did not increase bioethanol production (24.72 ± 0.07 g L-1 ), fermentation time reduction in 3 hours is a promising result because it optimizes the process. However, the urea addition of on fermentation medium resulted in a lower bioethanol production (18.31 ± 0.25 g L-1 ), possibly caused by the yeast metabolic deviation for the other biocomposites production. The fermentative volume increase in the bioreactor results in a similar bioethanol production (20.8 g L-1 ) obtained in Erlenmeyer, being a positive indication of the scale expansion possibility. This study highlights the potential fruit residues uses as a sustainable method to be explored for accelerating the bioethanol production chain.