ISSN 2736-1756
Advanced Journal of Microbiology Research Vol. 2015
Available online at http://internationalscholarsjournals.org/journal/ajmr
© 2015 International Scholars Journals
Full Length Research Paper
Study on b-galactosidase enzyme produced by isolated lactobacilli from milk and cheese
Elmira Gheytanchi1, Fariba Heshmati1, Bahareh Kordestani Shargh1, Jamileh Nowroozi1 and
Farahnaz Movahedzadeh2
1Department of Medical Microbiology, Medical School, Iran University of Medical Sciences, Hemmat High way, P. O. Box 14155-6183, Tehran, Iran.
2University of Illinois, Chicago, USA.
Accepted 22 December, 2014
Abstract
-galactosidases enzyme have been used in the dairy industry for the improvement of lactose intolerance. The aim of this study was to detect b-galactosidase enzyme produced by isolated lactobacilli from milk and cheese. 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) and O-nitrophenyl- -D-galactopyranoside (ONPG) was determined. A protein band of indicated b-galactosidase enzyme was also detected by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) method. The colonies that produced green color on X-Gal plates were lactobacilli with b-galactosidase enzyme which had ONPG positive results. The highest enzymatic value (1,966 U/ml) was observed in one strain of Lactobacillus delbrueckii. A 116 kDa protein band was detected in some strains (37%) with highest enzyme value and in others (63%), protein band was weak by SDS-PAGE method. By adding Lactobacilli producing b-galactosidase enzyme as probiotic to dairy products, could help lactose intolerant people.
Key words: Lactobacillus, -galactosidase, X-Gal, ONPG, SDS-PAGE.