Comparação da eficiência da fermentação alcoólica entre leveduras naturais da cana-de-açúcar e levedura comercial

Abstract

Sugarcane harbors a diverse microbiota that can directly influence the performance of alcoholic fermentation, particularly when native yeasts exhibit adaptation to the substrate and to the stress conditions of the process. This study aimed to isolate, identify, and characterize native yeasts associated with the stalks of three sugarcane varieties (RB 855453, RB 92579, and RB 855156) and to compare their growth with that of a commercial strain widely used in industry (S. cerevisiae CAT-1), with the goal of selecting candidates with biotechnological potential. Initially, sequencing of isolates from fresh sugarcane juice indicated a predominance of non-Saccharomyces yeasts, suggesting a low initial abundance of S. cerevisiae in the juice. To enrich the target genus, the juice was subjected to 24 h of spontaneous fermentation (30 °C; 200 rpm), which resulted in amplicons compatible with the positive control and in the detection of Saccharomyces cerevisiae after sequencing. In the physiological performance stage, growth curves showed that five native strains (855453-26, 855453-27, 92579-25, 92579-26, and 92579-31) exhibited growth superior or comparable to that of CAT-1, indicating potential competitiveness in a fermentative context. It is concluded that sugarcane is a relevant source of yeasts with industrial potential and that prior fermentative enrichment is an effective strategy to recover S. cerevisiae from sugarcane juice, providing promising strains for future validation regarding ethanol production, sugar consumption, and tolerance to process-related stresses.