Sustainable Biorefinery: Converting whey into valuable products using an enzymatic membrane

More than 21 million tons of cheese whey are produced annually worldwide, posing an environmental risk if not properly managed. Due to widespread lactose intolerance, cheese whey, which contains lactose, can pose health problems for many individuals. Thus, the management of the cheese whey is necessary to avoid environmental and health problems. This study presents a sustainable approach for whey valorization by integrating ultrafiltration and enzymatic hydrolysis by immobilizing β-galactosidase on a ceramic membrane. This approach offers a more efficient alternative to traditional whey processing methods by simultaneously concentrating proteins and hydrolyzing lactose leading to valuable products and waste minimization. The concentrated proteins can be further processed for various food applications, while the hydrolyzed lactose can be used for lactose-free products, biofuels, and biopolymers production. The enzyme immobilization was performed by using gelatin, followed by glutaraldehyde and different β-galactosidase concentrations (1.25-15 g/L).The enzymatic membrane's performance was evaluated by filtering acidic whey, separating the hydrolyzed lactose in the permeate and the concentrated protein in the retentate. A higher enzyme concentration led to increased immobilization efficiency and lactose hydrolysis as more enzymes attached to the empty sites on the ceramic membrane. However, after a certain concentration, the immobilization efficiency remained unchanged. An enzyme concentration of 5 g/L yielded in the optimal immobilization efficiency of 64%. The enzymatic membrane demonstrated promising catalytic activity, achieving lactose hydrolysis of 72% and protein rejection of 83%.At the end of each experiment, the membrane was chemically cleaned with a flux recovery of around 90%. This integrated approach contributes to the development of sustainable biorefinery technologies that can help address global challenges related to resource scarcity and environmental pollution.