In this study, in order to evaluate the enhancing effects of probiotics in co-aggregation with yeast, natamycin (Natamax, Danisco) was used at final concentration of 50ppm to inactivate yeast growth when pouring plating at 37o C in 48 h (Liu et al., 2009). | Tạp chí Công nghệ Sinh học 14(3): 549-555, 2016 SURVIVAL OF PROBIOTIC LACTOBACILLUS ACIDOPHILUS IN ACIDIC ENVIRONMENT IS ENHANCED IN THE PRESENCE OF SACCHAROMYCES CEREVISIAE Le Nguyen Han, Dong Thi Anh Dao Ho Chi Minh City University of Technology Received: Accepted: SUMMARY A number of health benefits have been proved for probiotic bacteria by many studies and probiotics are increasingly incorporated into foods. However, these market preparations have shown low viability of probiotics in human digestion. Therefore, providing viable probiotic cells to the colon and maintaining their metabolic activity against severe conditions of human digestion are increasingly interested by many recent scientific researches. In this trend, our research showed that by creating a physical barrier, the presence of Saccharomyces cerevisiae (SC) in Lactobacillus acidophilus (LA) suspension can effectively protect probiotic cells from stresses of digestion. After 150 minutes in simulated gastric juice, the survival of LA is significant improved (). Hence, this suggests that each certain LA concentration requires a critical SC concentration which once is surpassed, LA viability shows no significantly different improvement. SC÷LA concentration at 1:10 which proves the most effective ratio for viability enhancing effect of SC was chosen as the optimal ratio for later experiments. So far, there have been different reports on finding a suitable concentration ratio between yeast and LAB, greatly depending on varying microorganisms examined and also shown dissimilar results. For instance, Phebe et al. (2015) demonstrated that in Mcllvaine’s buffer solution pH = 2, 1÷1 ratio of L. rhamnosus HN001 to viable SC concentration is needed to effectively protect LAB in acidic environment. In their studies, the initial L. rhamnosus ± Log CFU mL-1 fell to ± 0,31 Log CFU mL-1, equivalent to viability. Meanwhile, Ningning et al., (2011) reported that they .
