Recovery and purification of lactose from whey

One of the main problems associated with the manufacturing of cheese is the production of whey, which causes environmental pollution due to its high concentration of dissolved organic substances, mostly proteins, fat and lactose. The search for economically viable and appropriate alternative uses of whey proteins and lactose is of fundamental importance. This work investigated four integrated processes, incorporating microfiltration, ultrafiltration, ion exchange, reverse osmosis and spray-drying, for the separation and purification of lactose from whey. The recovery and the purity of the final lactose product recovered were evaluated. It was shown that the process comprising of microfiltration (nominal pore size 0.2 μm), ultrafiltration UF3 (molecular weight cut-off 5 kDa), ion exchange and reverse osmosis, a lactose purity of 99.8% (including 4.2% of galactose/glucose) and an overall lactose recovery of 74% were obtained. The lactose left over in the retentate and trapped in the membrane modules and ion exchange columns could be further recovered to improve the overall recovery.