Growth medium Pi concentration affects stress resistance and metabolic traits of Lactiplantibacillus plantarum CRL 1905

ARAOZ, MARIO; GRILLO PUERTAS, MARIANA; HEBERT, ELVIRA M.; VILLEGAS, JOSEFINA M.; RAPISARDA, VIVIANA A.

Mendoza

Congreso; SAIB 2022; 2022

SAIB

Lactic acid bacteria (LAB) are a group of microorganisms that have multiple biotechnological applications. LAB used in foodproduction or as probiotics are subjected to harsh conditions derived from industrial processes or from the passage through thegastrointestinal tract. Thus, stress adaptation and survival play a crucial role in the robustness of strains. Polyphosphate (polyP) isa linear polymer formed by orthophosphate (Pi) residues, which is involved in response to stressful conditions in bacteria. Theability of Lactiplantibacillus plantarum CRL 1905 to maintain high levels of polyP in stationary phase was previously evidencedin a chemically defined medium (CDM) containing high Pi content (60 mM). In this condition, cells showed an increased viability through time, as well as an up-regulation of proteins involved in the main metabolic pathways, indicating an improved metabolismin late stationary phase. The aim of this study was to evaluate whether media Pi concentration affects metabolites production andstress resistance in L. plantarum CRL 1905. A HPLC analysis on supernatants obtained from cells grown for 24 and 48 h in CDMsupplemented with 2 and 60 mM of Pi (CDM-P and CDM+P, respectively) was carried out, showing a higher lactic acidaccumulation, as well as a faster glucose consumption by cells grown in the high Pi condition when compared to those grown inCDM-P. In addition, 48 h-cells grown in both media were subjected to several stressors (NaCl, H2O2, freeze-drying, andgastrointestinal tract simulation solutions). In all cases, an enhanced survival of the cells grown in high Pi medium in respect tothose grown in CDM-P was observed. The intracellular polyP levels in CDM+P decreased after the exposure to different stressors,an already known survival strategy for bacteria. It is worth to mention that after freeze-dried process, CDM+P cells maintainedtheir antimicrobial activity against pathogenic bacteria. Our results demonstrate that variations in media Pi concentration alter theproduction of main organic acids and resistance to different stressful conditions in CRL 1905 strain.