Isolation, characterization and screening of lactic acid bacteria (Lab) from fruits for the production of probiotic beverage

Abstract

The study was aimed to isolate, characterize and screen the efficient lactic acid bacteria (LAB) from different fruits which had probiotic properties. Naturally associated fifteen lactic acid bacterial isolates were isolated from different fruits. Isolation and identification of isolates were conducted according to the Bergey’s manual (conventional method) and based on morphological, physiological and biochemical characterization. Morphologically distinct colonies were studied for their cell morphology. All LAB isolates were rod shaped, gram positive, non-motile, and non-endospore producers. Biochemical characterization of isolates showed negative results for catalase test whereas, they were positive for acid production, dextran production, casein hydrolysis, gelatin liquefaction and starch hydrolysis test. Utilization of different carbon sources by lactic acid bacterial isolates showed positive results. Isolates were screened for probiotic characters like tolerance to low pH (2.0, 2.5 and 3.0), bile salts (0.1, 0.2 and 0.3%) and phenol (0.1, 0.2 and 0.3%). Among all fifteen isolates, LAB-12 and LAB-14 showed maximum potential probiotic characters. Further these two isolates were used for the fermentation of watermelon juice.