An integrated membrane system for the biocatalytic production of 3′-sialyllactose from dairy by-products

[Display omitted] •PLCC regenerated cellulose membrane (5kDa) can be used to configure the EMR.•NTR7450 membrane can be used for separation of 3′-sialyllactose and lactose.•Lactose can be concentrated and recycled by NF45 membrane.•Tr6 sialidase can be reused in the EMR and retain the activity after centrifugation.•CGMP residues accumulated in the EMR results in a flux decline and need to be removed. An integrated membrane system was investigated for the production of 3′-sialyllactose by an engineered sialidase using casein glycomacropeptide (CGMP) and lactose as substrates. CGMP was purified by ultrafiltration (UF) to remove any small molecules present and then an enzymatic membrane reactor (EMR) was used to separate the product and reuse the enzyme. A PLCC regenerated cellulose membrane was found to be the most suitable for both the UF purification and EMR. Subsequently, nanofiltration (NF) was conducted to increase the purity of the 3′-sialyllactose by removing the excess lactose present. The NTR7450 membrane outperformed others in NF due to its high retention of 3′-sialyllactose (98%) and relatively low rejection of lactose (40%). The lactose in the permeate could be concentrated by the NF45 membrane and recycled into the EMR. The described integrated membrane system enables a more economic and efficient enzymatic production of 3′-sialyllactose.