Isolation, Selection and Characteristics of<i>Lactobacillus paracasei</i>subsp.<i>paracasei</i>F19

Abstract

Lactobacillus strains were isolated from the deep colonic mucus layer of patients without gastrointestinal disease and screened for binding of porcine mucin. Strains exerting high mucin binding were further characterized as to survival ability in the gastrointestinal tract, viz pH stability and bile tolerance. Lactobacillus F19, identified as Lactobacillus paracasei ssp paracasei , bound gastric and bovine mucin, collagen I and III and fibronectin (Fn), and expressed high surface hydrophobicity. It survived exposure to pH 2.5 for 1 h and 20% bile for 2 h, had proteolytic activity and produced bacteriocin(s). It should thus have good possibilities to survive the passage through the gastrointestinal (GI) tract and establish in the GI mucin. Lactobacillus F19 transcribed NF- ? B to the nucleus of macrophages, and may thus have immunomodulatory effect. Keywords: Lactobacillus , paracasei , F19, isolation, bile, survival, binding.