Isolation and Identification of Saccharomyces cerevisiae var boulardii and its Uses as a Probiotic (in vitro)

The study included isolation and identification of Saccharomyces cerevisiae var. boulardii from fresh and dried fruits such as (fig, grape, apricot, lychees, mangosteen) which were available in local markets in Erbil city. Fifty isolates of the yeast were obtained depending on morphological, physiological and biochemical tests. The antibacterial activity of the isolated yeasts against pathogenic bacteria Salmonella enteric sub spp.enterica (Typhimurium) in vitro was determined by Well's Diffusion method. Most of the isolated yeasts showed antibacterial activity against tested bacterium, the highest diameter of inhibition zone was (16 mm) for isolates (S.b32). The ability to tolerate different concentrations of bile salt and gastric acids were also studied. Ten strains of the isolated yeast had the highest inhibitory activity and were used to study physiological properties (bile salt concentration and gastric acidity) which were (S.b6, S.c1, S.b2, S.c36, S.b13, S.b28, S.b32, S.b22, S.b48, and S.b5). The result showed that the isolate (S.b32) was more resistant than other strains when exposed to bile salt and gastric acids.