Heterologous Expression of BetL, a Betaine Uptake System, Enhances the Stress Tolerance of Lactobacillus salivarius UCC118

• Published in: Applied and Environmental Microbiology 2006-03, Vol.72 (3), p.2170-2177
• Main Authors: Sheehan, Vivien M, Sleator, Roy D, Fitzgerald, Gerald F, Hill, Colin
• Format: Article
• Language: English
• Subjects: abiotic stress; Anti-Bacterial Agents - pharmacology; bacterial proteins; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; betaine; Betaine - metabolism; Biological and medical sciences; Biotechnology; Carrier Proteins - genetics; Carrier Proteins - metabolism; cold stress; Colony Count, Microbial; cooling; freeze drying; Freezing; Fundamental and applied biological sciences. Psychology; gene expression; gene induction; genetically engineered microorganisms; Heat-Shock Response; Lactobacillus - genetics; Lactobacillus - growth & development; Lactobacillus - metabolism; Lactobacillus - physiology; Lactobacillus salivarius; Listeria monocytogenes; Listeria monocytogenes - genetics; Listeria monocytogenes - metabolism; Microbiology; nisin; Nisin - pharmacology; nisin-controlled gene expression; Osmolar Concentration; osmoregulation; osmotic pressure; physiological transport; Physiology and Biotechnology; pressure treatment; probiotics; spray drying; stress tolerance
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/AEM.72.3.2170-2177.2006

Given the increasing commercial and clinical relevance of probiotic cultures, improving the technological robustness of what are often process-sensitive cultures is an important biological goal. The nisin-controlled expression system was used to direct the heterologous expression of the listerial betaine uptake system BetL in the probiotic strain Lactobacillus salivarius UCC118. Following nisin induction, strains expressing betL exhibited a significant increase in resistance to several stresses, including elevated osmo-, cryo-, baro-, and chill tolerance, as well as increased resistance to spray- and freeze-drying. The ability to confer additional stress tolerance on a probiotic culture may be an important step in delivering viable cultures for maximal efficacy.