Lactose is hydrolyzed in small intestine by β-galactosidase (Lactase) however, when a person has some kind intolerance to lactose the symptoms caused by the excess of lactose not hydrolyzed can be abdominal cramps, bloating, flatulence, loose stools and diarrhea. During the last decades, immobilized lactase has been attracted great attention by food and pharmaceutical industry due to the new opportunity to degrade whey lactose using β-galactosidase in situ and in vivo. The formation of complexes between β-Galactosidases and biopolymers represents a great opportunity to immobilization of lactase and creates a new biofuncional material. The objective of this research project was to evaluate the yield of lactase immobilization in the formation of complex between β-Galactosidase (Kluyveromyces lactis) and sodium alginate determining the temperature profile, thermal stability, pH profile, pH stability and kinetic parameters of the immobilized and free lactase. In general, we can note that the ratios studied during the complexation affected directly the critical pHs and the diameter of the complexes formed, but in the ratio 5: 1, pH 3.7, the immobilization yield reached 97.26 ± 2.44%. After analysis with the scanning electron microscope, the complexes showed that interpolymeric complexes were formed during the interaction of the biopolymers. When evaluating the kinetic parameters of the native enzyme and the complexes formed, it was possible to suggest that the complexation did not affect negatively the kinetic parameters of the enzyme. Finally, when evaluating the effect of pH and temperature on complexed and native enzyme activity, it can be seen that the complexes have protected the enzyme against prolonged exposure in acidic environments, which makes the application of this technology promising in the food industry.