Determining Acid-Bile Optimization and Correlation between Optical Density and the Colony Forming Units of Lactobacilli Species

Optimizing Acid-Bile Tolerance of Lactobacilli

Abstract

Different research practices are being done with time to check the fruitful aspects of probiotics administration in food. In this regard, a specific number of probiotics is mixed in the food and presented to the experimental animals in laboratory to the fruitful impacts of probiotics on host. Objective: To design the standard curve between optical density and the number of colony-forming units. Methods: Lactobacilli species were grown in broth and their colony forming units (CFU) were calculated at different dilutions. In addition to this, relationship between optical density and number of colony forming units and acid-bile tolerance of these Lactobacilli species were also found out. Results: It was observed that L. paracasii, L. delbrueckii, L. rhamnosus, and L. brevis showed optimum rates with the Mean±SEM values of 2.56±0.04 on pH 7, 2.51±0.04 on pH 7.5, 2.46±0.04 on pH 7.5 and 2.54±0.02 on pH 7 respectively (p <0.0001). Similarly, all these isolates (L. paracasii, L. delbrueckii, L. rhamnosus, and L. brevis) showed maximum growth rates on bile concentration of 0.1, and their Mean±SEM values of optical densities were 1.83±0.10, 2.36±0.25, 2.50±0.31, 1.58±0.10 respectively (p <0.0001). Means were compared by ANOVA employing SPSS 20.0. Conclusions: The study provided insights in conducting different research practices on probiotics in future.