Screening of Bacillus Species Obtained from Dairy Environmental Samples for their Salient Probiotic Features

Abstract

Aims: To screen the Bacillus species for important probiotic features such as acid tolerance, bile tolerance and hydrophobic characteristics.  Study Design: Bacillus species (19) obtained from dairy environmental samples were subjected for Confirming their acid, bile tolerance with adhesion ability. Place and Duration of Study: The study was conducted at Department of Dairy Microbiology, Dairy Science College, KVAFSU, Hebbal, Bengaluru (Karnataka), India for a period of one year. Methodology: For screening of Bacillus spp. acid and bile tolerance, nutrient broth adjusted to pH 2.0 and nutrient broth with 0.3 per cent ox bile at pH 7.0 which are considered to the simulation of gastrointestinal condition were adopted followed by survivor counts by pour plating.  In order to check the hydrophobic nature which indirectly provides the index of the attachment of Bacillus spp to intestinal epithelial cells xylene was used as the solvent. Results: A total of 19 numbers of isolates of Bacillus spp were obtained from the dairy environmental samples which included 3 from air sample followed by 2 from each of dung, silage, udder swab, hand swab & can rinse and one isolate from samples of soil, feed, fodder, can milk, aseptic milk and water. Among 19 isolates, B7 and B12 exhibited higher survivability (%) with respect to acid accounting for 96.20, 99.52 and bile of 99.32 and 98.57, respectively. B7 & B12 isolates revealed 37.7 and 38.7% of adhesion ability, respectively. Conclusion: Among 19 isolates of Bacillus spp., B7 and B12 expressed higher survivability with respect to acid as well as bile in simulated human gastrointestinal environment along with good adhesion capacity indicating that these two isolates can be further explored as probiotics in food or feed for improving the gut health of the hosts.