Characterization of Lactobacilli Isolated From Four Different Sources

Lactobacilli, the Gram positive, non spore forming, catalase negative rod shaped lactic acid bacteria are used widely as starter cultures for food fermentations and also as probiotic cultures due to their functional attributes. In this study, four lactobacilli each isolated from different sources namely: carrot, idli batter, dahi and duck feces were assessed for various attributes like antimicrobial, bile salt hydrolysis, proteolytic and lecithinase activities and their ability to grow at different salt concentrations. All the isolates were able to grow in salt concentrations as high as five percent and possessed bile salt hydrolase, an enzyme that imparts bile salt tolerance. All of them were also found to be antagonistic against S. aureus with the isolate from carrot giving the largest zone of inhibition of 16mm diameter. Two of the isolates were found to be moderately proteolytic and none of the isolates showed lecithinase activity.