Inorganic salts and intracellular polyphosphate inclusions play a role in the thermotolerance of the immunobiotic Lactobacillus rhamnosus CRL 1505.

ABSTRACT: In this work, the thermotolerance of Lactobacillus rhamnosus CRL1505, an immunobiotic strain, was studied as a way to improve the tolerance of the strain to industrial processes involving heat stress. The strain displayed a high intrinsic thermotolerance (55°C, 20 min); however, after 5 min at 60°C in phosphate buffer a two log units decrease in cell viability was observed. Different heat shock media were tested to improve the cell survival. Best results were obtained in the mediumcontaining inorganic salts (KH2PO4, Na2HPO4, MnSO4, and MgSO4) likely as using 10% skim milk. Flow cytometry analysis evinced 25.0% live cells and a large number of injured cells (59.7%) in the inorganic salts medium after heat stress. The morphological changes caused by temperature were visualized by transmissio

SUBMITTER: Correa Deza MA 

PROVIDER: S-EPMC5464658 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature