Isolation, Characterization and Probiotic Value of Lactic Acid Bacteria from Milk and Milk Products Bisht Neha1, Garg A. P.2,* 1Department of Microbiology, Ch. Charan Singh University, Meerut-250004, India 2Shobhit Institute of Engineering and Technology (Deemed to be University), NH-58, Modipuram, Meerut-250110, India *Corresponding Author E-mail: amarprakashgarg@gmail.com
Online published on 23 May, 2020. Abstract In present study we have isolated and characterized lactic acid bacteria (LAB) from milk and milk products. Based on their physiological and biochemical properties, the isolates were found to belong the genus Lactobacillus. The isolates were also tested for their ability to produce extracellular enzymesamylases, lipases, phytases, proteases and gelatinases. Further, isolates were examined for their potential probiotics attributes like-acid, bile and pancreatin tolerance; haemolysis and antibiotics susceptibility. Four of the species L. brevis, L. fermentum, L. acidophilus and L. rhamnosus showed amylases activity, while L. brevis, L. plantarum, L. acidophilus and L. rhamnosus showed clear zones of precipitation of tributyrin suggesting lipase positive. All the isolates showed a halo zone around the colonies and were phytase positive. Only L. casei, L. rhamnosus and L. helveticus showed a proteolytic activity. Absence of gelatinase activity was a selection criteria for probiotic strains which indicated that these bacteria were non-virulent and all the isolates were found gelatin negative. L. brevis showed highest tolerance in the acidic medium (pH3) and pancreatin (0.5% w/v). At pH 2.5 the maximum tolerance was shown by L.acidophilus, while L.acidophilus and L. fermentum showed highest bile tolerance. Top Keywords Lactic acid bacteria, amylases, lipases, phytases, proteases, gelatinases, acid, bile and pancreatin. Top |