ABSTRACT
@#Aims: The present study deals with the isolation and identification of lactase producing probiotic strains from camel and sheep milk, determination of the enzyme activity by β-galactosidase assay (Miller Assay) in the presence of garlic, peas, onion and leeks extracts containing inulin as a prebiotic component. Methodology and results: The two isolates were screened for lactase producing ability to degrade lactose on MRS agar at 37 °C. These were identified as Lactococcus lactis from camel (Marecha) milk and Lactobacillus casei from sheep (Kajli) milk through morphological and biochemical tests using MRS medium. The optimized pH and temperature of both strains were 6 and 35 °C, respectively. Among the three concentrations used (0.2%, 0.4%, 0.8%), the optimal concentration of inulin rich onion and leeks extracts was 0.8% for maximum growth of L. casei and of the peas extract for L. lactis growth. 0.2% garlic extract was more effective prebiotic source for L. lactis growth. 0.8% commercial inulin used as a positive control was less effective as compared to plant extracts used in the study. With o-nitrophenyl-β-Dgalactoside) used as a substrate in the enzyme assay, maximum lactase activity obtained with 0.8% concentration of garlic extract is 7.10 Miller Units as compared to the peas extract with 6.17 Miller Units from L. lactis. Lactobacillus casei has produced more lactase, 6.85 Miller units with onion extract than with leeks extract, 6.43 Miller Units. Pure commercial inulin used as a control has given maximum enzyme activity as 9.14 Miller Units at 0.2% concentration. Conclusion, significance and impact of the study: It is concluded that the extracted prebiotic may enhance lactase activity of the probiotics to supplement the development of food products for lactose intolerant patients.