Abstract
Six strains of L. reuteri and 9 bifidobacteria strains were screened for the activity of alpha-and beta-galactosidases. Enzymatic activities were measured by determining the rate of hydrolysis of rho-nitrophenyl-alpha-D-galactopyranoside and o-nitrophenyl-beta-D-galactopyranoside, respectively. Findings show that alpha-galactosidase activity in L. reuteri (0.067-0.603 Gal U/ml) was higher than that produced by bifidobacteria (0.013-0.396 Gal U/ml). alpha-Galactosidase activity of L. reuteri strains DSM20016 and MM2-3 were higher in comparison with the other bifidobacteria. DSM20016 had the highest alpha-galactosidase activity (0.603 Gal U/ml) among L. reuteri strains. beta-Galactosidase activities for L. reuteri and bifidobacteria were in the range of 3.1x10(-4)-9.36 and 0.062-17.59 Gal U/ml, respectively. L. reuteri MF14C showed the highest beta-galactosidase activity (17.59 Gal U/ml). L. reuteri strains MF14C and DSM20016 (12.87 Gal U/ml) showed higher beta-galactosidase activity than bifidobacteria. Since L. reuteri is considered as Generally Regarded As Safe (GRAS), this could support the use of this bacteria in food industry.