Isolation and Biochemical Characterization of Lactic Acid Bacteria from Fermented Foods

Abstract

Probiotics are considered as successful major category of food supplements. Probiotics can be functional foods because their health benefits are essentially higher than traditional nutritional products. Probiotic bacteria was collected from home made and commercial fermented food samples. A total of 30 food samples were collected from local areas of Guntur in Andhra Pradesh. Bacteria were isolated on MRS agar medium after observation of growth and pure culture was obtained by sub-culturing on the same medium. Purity of each culture was confirmed by morphological investigation, Gram’s staining and further identification by specific biochemical tests. The isolates from both dairy and non-dairy fermented foods were identified as rods, bacilli, cocci and chain shape. While some isolates showed positive results some showed negative results for catalase test, methyl red test, oxidase test, aescualin fermentation, starch hydrolysis, arginine hydrolysis, citrate utilization and voges prausker’s test reaction. Based on morphological, cultural and biochemical characterization of 16 bacterial isolates out of 30 were identified as Lactobacillus spp.