Beta-galactosidase activity in psychrotrophic microorganisms and their potential use in food industry

Twenty-one psychrotrophic resp. psychrophilic bacterial strains were screened for presence of b-galactosidase activity which showed 8 of them. b-Galactosidase activity of these strains was determined for 2 substrates - synthetic substrate (ONPG) and lactose - and also temperature profile of this enzyme was measured. b-Galactosidase from Arthrobacter sp. C2-2 not only proved the typical properties of cold-active enzyme, but it also preferred lactose as a substrate. Therefore, it was chosen for further isolation and purification and was found that it contains two b-galactosidase isoenzymes. One of them had strong preference for lactose and was able to catalyse transglycosylation reactions at low temperature. It has, thus, potential use in food technology.