Screening and characterization of β-Galactosidase producing Lactobacillus sp. isolated from dairy samples

Lactose intolerance in humans is the major concern in current scenario. β-Galactosidase has tremendous potential in the preparations of lactose free product development. The present research was carried out to screen β-Galactosidase producing Lactic acid bacteria (LAB) from milk and milk products such asdonkey milk, Curd and yogurt. Based on the morphological characteristics, about 70 bacterial colonies were selected. Out of these, 5 isolates from donkey milk, 7 from curd and 3 from yogurt sample were found positive for β-Galactosidase production using X-Gal method. Potent strains were identified by determining the enzyme activity using ONPG assay. The maximum enzyme activity was found in isolate no. VITDM15 (Donkey milk) with of 375.21 AU/ml followed by 235.36 AU/ml from VITCD01(Curd) and 142.35 AU/ml from VITYT13(Yogurt) respectively. Hence these strains can be exploited for lactose free product development.