Fermentação alcoólica de polpa de melancia utilizando uma nova espécie de wickerhamomyces isolada de madeira em decomposição

Abstract

This study aimed to evaluate a sequential batch fermentation strategy with cell recycling for ethanol production. The process was carried out using watermelon residue as a substrate and the yeast Wickerhamomyces sp. UFFS-CE-3.1.2 as a fermenting microorganism. The initial experiments were conducted to evaluate the residue’s potential and the fermenting microorganism for ethanol production. The results showed that the yeast Wickerhamomyces sp. UFFS-CE-3.1.2 has the potential for ethanol production on a watermelon residue substrate, demonstrated by the efficiency of 95% fermentative efficiency in 9 h of process, the reduced glycerol yield, the cell propagation capacity, and the dispensing supplementation with nitrogen source, and for presenting fermentative capacity similar to Saccharomyces cerevisiae CAT-1. Then, the sequential batch fermentation strategy with cell recycling was initiated and conducted over thirty cycles. The results showed a 6 h reduction in the fermentation time after six fermentation cycles. In addition, the fermentation carried out in sequential batches benefited cell propagation, highlighting the fourfold increase in productivity. The yeast fermentation capacity was maintained throughout the thirty batches, with yields above 90% of the theoretical yield. The adaptation action by selective pressure was evaluated by the isolation of colonies from the cell group of the thirtieth recycle, which when exposed to different carbon sources showed a statistical difference, highlighting the consumption of glucose and xylose. The use of residual watermelon pulp as a substrate for alcoholic fermentation in a sequential batch strategy with cell recycling of an unconventional yeast is a novelty in this study.