Cinética de crescimento de leveduras nativas em diferentes fontes de carbono e temperatura

Abstract

This study aimed to analyze the growth kinetics of native yeast strains isolated from sugarcane cultivated in the region of Areia, Paraíba (Brazil), with a view to their application in alcoholic fermentation processes. Three strains (2506S, 2754S, and 3129I) were selected for evaluation under different cultivation conditions, using three carbon sources (sucrose, glucose, and maltose) and three temperature ranges (15 °C, 30 °C, and 37 °C). The experiments were conducted in an orbital shaker under controlled temperature, according to the parameters established for the pre-inocula. After the growth period, the cultures were standardized to a concentration of 10⁸ CFU/mL and distributed into 96-well microplates, maintained under the same temperature conditions. Readings were performed using an ELISA-type microplate reader every two hours during the first 12 hours of cultivation, and subsequently every 12 hours. The analyses were conducted by determining cell growth curves, the maximum specific growth rate (𝜇𝑚𝑎𝑥), and the generation time (𝑡𝑔). The results showed that strain 2506S exhibited the best performance at 15 °C and 30 °C, with high 𝜇𝑚𝑎𝑥values and short generation times, indicating strong growth potential under these conditions. In contrast, elevated temperatures (37 °C) resulted in reduced performance for strains 2506S and 2754S, suggesting thermal sensitivity. Strain 3129I, in turn, showed more stable behavior across all tested temperatures and carbon sources. These findings are consistent with the literature, which indicates 30 °C as the optimal range for the growth of Saccharomyces cerevisiae, with decreased cellular activity at supra-optimal temperatures. The thermal and nutritional stability of strain 3129I highlights its potential for industrial use in processes subject to operational variability. Additionally, the high cell concentration reached by strain 2506S at 15 °C at the end of the exponential phase suggests its feasibility for fermentative processes at lower temperatures. These findings reinforce the importance of prospecting native microorganisms as a strategy for developing more efficient, robust, and regionally adapted fermentations.