Recovery of whey proteins and lactose from dairy waste: A step towards green waste management

• The recovery of lactose and protein from casein whey using hollow fiber membranes.
• For commercialization, recovered lactose and protein were freeze-dried.
• The qualitative confirmation lactose and protein was done using FTIR.
• Recovered lactose and protein has appreciable economic values.
• The proposed method can reduce detrimental effect of whey on the environment.

Whey is produced as a by-product during cheese and casein manufacture containing some important components such as lactose and protein. In this study, ultrafiltration process was adopted to separate lactose and protein with high yield and purity from whey using hollow fiber module. Ultrafiltration in a diafiltration mode was used in order to improve the yield of protein in the retentate, which was then freeze-dried to get the end product in dried form. Nanofiltration of the permeate stream from ultrafiltration was done to concentrate the lactose part and was similarly freeze-dried. To assure that after freeze–drying the quality of both the protein and lactose was not affected, FTIR analysis was done. The performance of both ultrafiltration and nanofiltration was characterized in terms of permeate flux. The influence of transmembrane pressure on both ultrafiltration and nanofiltration membranes was studied. The effect of fouling was also studied on both ultrafiltration and nanofiltration membranes and it was observed that the fouling effect was less in case of both the membranes and as such the membranes could be re-used for several times for effective separation of those components. The quantitative measurements were done for lactose and protein and it was observed that up to 90% of lactose and 80% of protein recovery could be achieved using the advanced separation technology. Therefore, the present article represents a novel approach for separation whey proteins and lactose from dairy waste to meet the socio economic requirements as well as to mitigate waste disposal problem.