Evaluation of Probiotic Potential of Stress Tolerant Saccharomyces cerevisiae and Development of Economically Viable Media for Maximum Growth

Abstract

The aim of this study is to characterize the probiotic potential of Saccharomyces cerevisiae MTCC 174, 3821 along with two yeast strains (GSM 3 and 9) isolated from fruit waste and toddy samples respectively. The efficiency of probiotic organisms are tested in vitro under the simulating stress conditions present in gastrointestinal tract i.e. acid and alkaline tolerance, bile salts survivability, thermo tolerance and osmo tolerance. Saccharomyces cerevisiae MTCC 3821 was able to tolerate temperature 43°C and GSM 3 tolerates (isolated yeast) up to 45°C, both the strains are able to tolerate pH range 2 to 8. Saccharomyces cerevisiae MTCC 3821, 174 and isolated yeast (GSM 3 and GSM 9) resisted bile salts concentration of 0.5% to 2% and survived in 30% glucose concentration. Effect of various carbon and nitrogen sources was studied on all the four strains. MTCC 3821 and GSM 3 produced good biomass of 6 g/L in sucrose, 5 g/L in beef extract and tryptone. Saccharomyces MTCC 3821 has also shown maximum biomass of 11.45 g/L (dry wt.) in developed combinational medium consisting of jaggery and beef extract. Based on 18s rRNA sequencing GSM 3 and GSM 9 were identified as Candida tropicalis. Among these organisms Saccharomyces cerevisiae MTCC 3821 is selected for further studies because the ability of the strain to tolerate stress conditions present in gastrointestinal tract (temperature-42°C, bile concentration 2%, pH-2).