Probiotic effects of Metschnikowia isolated from dairy products aquatic environments

The aim of this study was to characterize the probiotic yeasts isolated from both aquatic environment and dairy products by sanger sequencing method and drawing phylogenetic tree for the identified probiotic yeasts. Sampling of dairy and non-dairy products was done randomly. Characterization of yeasts was constructed by molecular strategies based on the amplification and sequencing of the ribosomal DNA internal transcribed spacer region. MEGA7 software was also applied for alignment (Muscle algorithm) and to create an agreement neighbour-joining analysis to determine the phylogenetic relationship of isolated species. For an in vitro selection of the probiotic candidates, survival of isolates at different temperatures, pH and bile salts was assessed. Based on biochemical assays and gene sequencing, the isolates were detected as Candida albicans (Wb), Clavispora lusitaniae (WC), Metschnikowia (KC) and Saccharomyces cerevisiae (Vc) strains. We indicated that Wb and KC isolates could significantly grow at 37°C after 3 hours. Wb, KC and Vc species also were proliferated at pH~1.5. We concluded that Wb and KC strains isolated from the marine environment and dairy products have great potential for use as probiotics in the food industry based on their resistance in human body at temperature equal to 37°C and gastric PH equal to 1.5.