Evaluating Lachancea thermotolerans for table olive fermentation: performance under pH and NaCl stress conditions

This study evaluates the biotechnological potential of Lachancea thermotolerans, a non-Saccharomyces yeast species commonly characterized by its ability to produce L-lactic acid, for its application in Spanish-style table olive fermentation. A total of sixty-six L. thermotolerans strains were assessed under varying pH and NaCl conditions, two key stress factors in table olive processing. Growth performance was determined through the analysis of growth curves and compared with those of Wickerhamomyces anomalus and Candida boidinii, two yeast species commonly isolated from table olive fermentations. To characterize strain behavior under stress conditions, growth parameters derived from the models were further analyzed using Principal Component Analysis and hierarchical clustering. These approaches enabled the classification of strains according to their tolerance to pH and salt stress, as well as the identification of groups with distinct growth kinetics. The results revealed significant variability among L. thermotolerans strains, highlighting a strain-dependent response to environmental stressors. A subset of strains exhibited high tolerance to both pH and NaCl conditions, demonstrating stable growth performance and suggesting a strong adaptive capacity. These findings support the potential application of selected L. thermotolerans strains as promising candidates for controlled table olive fermentation processes.