JOURNAL OF PURE AND APPLIED MICROBIOLOGY, March 2013. Vol. 7(1), p. 595-601 * To whom all correspondence should be addressed. Mob.: +91-9452267383, +91-0542 2277296; Fax: +91-542- 2277587; E-mail: deepmala.katiyar@gmail.com Influence of UV Treatment on β β β β β -galactosidase Produced by Lactobacillus plantarum Bharati Singh 1 , Deepmala Katiyar 1 *, Rajveer Singh Chauhan 2 , Rajesh K. Kharwar 3 and Alok Milton Lall 4 1 Vitaegen Biotech- Educational and Research Institute, Varanasi, India. 2 Departments of Botany, Faculty of Sciences, University of Lucknow, Lucknow, India. 3 Department of Zoology, Faculty of Sciences, Banaras Hindu University, Varanasi India. 4 Department of Biochemistry & Bioprocess Technology, Sam Higginbottom Institute of Agriculture, Technology and Sciences, Allahabad, India. (Received: 05 August 2012; accepted: 26 September 2012) Lactose hydrolyzing enzyme, β-galactosidases have been used in the dairy industry for the improvement of lactose intolerance. The aim of this study was to detect β-galactosidase enzyme produced by isolated Lactobacillus Plantarum from milk and cheese and effect of UV treatment on b-galactosidase. Isolated lactobacilli were cultured on MRS agar. Lactobacilli were identified by Gram stain and standard bacteriological and biochemical methods. Their ability to hydrolyze 5-bromo-4-chloro-3-indolyl-D- galactopyranoside (X-Gal)andO-nitrophenyl-D galactopyranoside (ONPG) was determined. A protein band of indicated β-galactosidase enzyme was also detected by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) method. The colonies that produced greenish blue color on X-Gal plates were lactobacilli with β-galactosidase enzyme which had ONPG positive results. The highest enzymatic value was observed in 15 minutes UV radiation and also to characterize its probable bactericins of Lactobacillus plantarum. By adding Lactobacilli producing β-galactosidase enzyme as probiotic to dairy products, could help lactose intolerant people. Key words: β-galactosidase, Lactobacillus Plantarum, UV treatment. Lactose is a disaccharide found in milk and other dairy products. Lactose indigestion in the intestinal microflora leads to dizziness, headache and nausea. So milk and other dairy products are manufactured with less lactose content for lactose intolerance people which further adds the cost to about 80% of the normal unhydrolysed milk 1 . One of the glycosidases, is β-galactosidase enzyme that widely used in dairy industry and is produced by most lactobacilli. 2, 3 This enzyme hydrolyzes lactose, the main carbohydrate in milk, into glucose and galactose, which can be absorbed across the intestinal epithelium 4 . β-galactosidase has two enzymatic activities: one is responsible for the hydrolysis of lactose and also cleaves cellobiose, cellotriose, cellotetrose and to a certain extent cellulose and the other, splits β-glycosides 5 . Low activity of β- galactosidase causes digestive insufficiency, called lactose intolerance in most cases 6,7 . The symptoms of lactose intolerance such as abdominal pain and diarrhea, nausea, flatulence, and or bloating after the ingestion of lactose or lactose containing food substances which can lead to decrease quality of life, and daily activities. Treatment is relatively simple by eliminating lactose