Response mechanisms of lactic acid bacteria under environmental stress and their application in the food industry

Lactic acid bacteria play a pivotal role in the fermented food industry by enhancing flavor, extending shelf life, and promoting gut health. However, during food production, lactic acid bacteria often encounter environmental stresses such as acidity, osmotic pressure, temperature fluctuations, oxidation, and starvation, which can severely impact their growth, metabolism, and overall performance. In response, lactic acid bacteria utilize various adaptive mechanisms, including the regulation of carbohydrate, amino acid, and energy metabolism, DNA protection and repair, and the synthesis of cell wall and membrane. Nevertheless, under extreme environmental stresses, these intrinsic mechanisms are often insufficient. To address these limitations, external protectants, traditional strain modifications, and histological modifications have been proposed to further enhance lactic acid bacteria's stress tolerance, thereby improving their performance in food production. Stress-tolerant lactic acid bacteria strains provide distinct advantages, including improved fermentation efficiency, greater product stability, and enhanced overall quality. This review summarized lactic acid bacteria stress response mechanisms, strategies for enhancing their tolerance. It also explored the potential applications of stress-tolerant lactic acid bacteria strains in the food industry, providing both theoretical and practical insights to optimize their use in food production and health-related applications.