MEDIA PHOSPHATE CONTENT INFLUENCES STRESS TOLERANCE AND BIOFILM FORMATION OF Lactobacillus paraplantarum CRL 1905

VILLEGAS, JOSEFINA MARÍA; ARAOZ, MARIO; GRILLO PUERTAS, MARIANA; HEBERT, ELVIRA MARIA; RAPISARDA, VIVIANA ANDREA

Buenos Aires

Congreso; LIII Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB). Reunión Conjunta de Sociedades de Biociencias; 2017

SAIB

Lactic acid bacteria (LAB) comprise a group of Gram positive microorganismscommonly used in food fermentation industry. Theyare usually exposed to a range of stressful environmental conditionsin both natural and/or industrial habitats, such as high temperature,low pH, nutrient starvation, and oxidation. Previous studiesshowed that media phosphate (Pi) content modulates polyphosphate(polyP) levels in different bacteria, affecting stress responses, stationary-phasesurvival, and biofilm formation. The aim of this workwas to investigate the effect of Pi concentrations on stress resistanceand biofilm formation of L. paraplantarum CRL 1905. IntracellularpolyP levels of the strain grown in chemically defined media (CDM)containing different Pi concentrations were determined. As control,CRL 1905 was grown in the routinely used rich medium MRS. It wasobserved that high polyP levels were maintained up to 120 h onlywhen cells were grown in CDM supplied with 60 mM Pi. The polyPaccumulation under this condition was correlated with a long-termcell survival, when compared to cells grown in CDM medium supplementedwith sufficient Pi; loss of viability over time was even morepronounced in the rich medium. CRL 1905 stationary-phase cellsgrown in 60 mM Pi were more tolerant to high temperatures thanthose grown in 2 mM Pi. However, there was no correlation betweenmedia Pi concentration and resistance to acidic and oxidant conditions.The biofilm-forming capacity of L. paraplantarum under differentculture conditions was characterized by microtiter plate biofilmassays. It was observed that a high Pi concentration in the mediumimpaired biofilm formation; this phenotype could be related to themaintenance of polyP in stationary phase. Taken together, this studycontributes to a better understanding of alternative mechanisms bywhich beneficial bacteria can counteract several stress conditionsand colonize different niches.