Simultaneous hydrolysis of cheese whey and lactulose production catalyzed by β-galactosidase from Kluyveromyces lactis NRRL Y1564.

β-Galactosidase was produced by the yeast Kluyveromyces lactis NRRL Y1564 in cheese whey supplemented with yeast extract under the optimal temperature of 30 °C, delivering an enzymatic activity of 4418.37 U/g after 12 h of process. In order to develop more stable biocatalysts, the enzyme produced by fermentation was immobilized on 2.