Milk lactose removal by β-galactosidase immobilized on eggshell membrane

Eggshell membrane (ESM) is used in immobilization studies due to its large surface area, non-toxicity and biodegradability. In this study, beta-galactosidase was immobilized on ESM using the adsorption and cross-linking method. The interactions between enzyme and ESM after immobilization were determined by ATR-FTIR (attenuated total reflection fourier transform infrared spectroscopy) and SEM (scanning electron microscope). The optimum temperature of the free enzyme was found to be 35 degrees C, and this value was 45 degrees C for the immobilized enzyme. Immobilized enzyme managed to retain more than 50% of its activity after 8 reuses. In the lactose removal experiment from milk, the highest reaction efficiency was found as 55.8% under specified optimization conditions for beta-galactosidase immobilized ESM after 3 h. Due to the microfiber protein structure of the ESM, it has improved enzyme stability properties, as a result of the multi protein-protein interactions formed after the immobilization between the proteins in the ESM and the enzyme molecules.