Stress Physiology of Lactic Acid Bacteria

Abstract

SUMMARYLactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g.,Lactococcus lactis), probiotic (e.g., severalLactobacillusspp.), and pathogenic (e.g.,EnterococcusandStreptococcusspp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the “stressome” of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.

Comparative proteomic analysis of four biotechnological strains Lactococcus lactis through label‐free quantitative proteomics

“…Lactococcus lactis is exposed to different stress conditions, such as acid stress, osmotic stress, thermal stress, oxidative stress and nutritional starvation, these perturbation have a direct effect in its physiologic state (Papadimitriou et al ., ). Thus, to confront the environmental changes, L. lactis need adjust its metabolism to adapt and survive the different stress conditions that are commonly found by this bacterium both in industrial fermentation and in the human digestive tract.…”

Dietary Fibers and Protective Lactobacilli Drive Burrata Cheese Microbiome

“…Microorganisms, including probiotic lactobacilli, metabolize FAA to obtain ATP and other compounds to survive under hostile abiotic conditions, such as acid and cold stresses (51,52). The decarboxylation of acid substrates (such as glutamic acid) into a neutral compound (GABA), by consuming an H ϩ , increases the intracellular pH (53,54). The catabolism of FAA by deaminase pathways producing ammonia is another common mechanism of probiotic lactobacilli for survival under acid and/or starvation stress (51,53).…”

“…The decarboxylation of acid substrates (such as glutamic acid) into a neutral compound (GABA), by consuming an H ϩ , increases the intracellular pH (53,54). The catabolism of FAA by deaminase pathways producing ammonia is another common mechanism of probiotic lactobacilli for survival under acid and/or starvation stress (51,53). The synthesis/liberation of FAA constitutes a key factor impacting the flavor of cheeses, and FAA catabolism, by forming volatile organic compounds, influences taste and aroma (55).…”

Technological characterization of vaginal probiotic lactobacilli: resistance to osmotic stress and strains compatibility

“…; Papadimitriou et al . ), expression of a set of proteins or quantitative proteomic (Schott et al . ) or glycine betaine transport (Han et al .…”