Isolation and Characterization of Lactobacillus spp. of Human Origin for Studying their Prevalence

A total of 15 samples of healthy human feces were collected for the isolation of lactobacilli using lactobacillus selection MRS agar. Thirty-eight colonies were randomly picked based on colonial morphology. All the isolates were subjected to cell morphology, physiology and an array of biochemical characterization. The isolates showed different growth patterns at different temperatures (15 and 45 °C), oxygen and at different concentrations of NaCl (2.0, 4.0 and 6.5%). On the basis of physiological tests and sugar utilization pattern, all the thirty eight isolates were confirmed to the different species of Lactobacillus (i.e., Lactobacillus plantarum (4), Lactobacillus casei (15), Lactobacillus rhamnosus (2), Lactobacillus fermentum (4), and Lactobacillus acidophilus (10), Lactobacillus helveticus (3). Among isolates Lactobacillus casei was found to be prevalent in the human gut. Keywords: Lactobacilli, biochemical characterization, human gut