Lactose hydrolysis by β-galactosidase enzyme: optimization using response surface methodology

Abstract

In the present study, it was aimed to optimize the process of lactose hydrolysis using free and immobilized β-galactosidase to produce glucose and galactose. Response surface methodology (RSM) by central composite design (CCD) was employed to optimize the degree of hydrolysis by varying three parameters, temperature (15–45°C), solution pH (5–9) and β-galactosidase enzyme concentration (2–8mg/mL) for free mode of analysis and sodium alginate concentration (2–4%), calcium chloride concentration (3–6%) and enzyme concentration (2–8mg/mL) for immobilized process. Based on plots and variance analysis, the optimum operational conditions for maximizing lactose hydrolysis were found to be temperature (35.5°C), pH (6.7) and enzyme concentration (6.7mg/mL) in free mode and sodium alginate concentration (3%), calcium chloride concentration (5.9%) and enzyme concentration (5.2mg/mL) in immobilized mode.