The possibility for improvement of ceramic membrane ultrafiltration of an enzyme solution

Ultrafiltration represents an attractive downstream processing technique for enzymes concentration and their primary purification. However, the process efficiency is often limited by protein fouling and shear-induced enzyme deactivation, resulting in permeate flux decline and loss of enzyme activity. The objective of this work was to investigate the possibility for improvement of ceramic membrane ultrafiltration of endo-pectinase solution. Experimental investigations were performed on a 5 nm ceramic membrane with the Kenics static mixer placed inside the membrane in order to improve the process performance. The use of the static mixer resulted in the flux improvement of about 45% at a volume concentration factor (VCF) of 3 leading to the reduction of operation time of 25% and the energy saving of about 40%. Although the rejection of endo-pectinase was higher than 96%, the extensive loss of the enzyme activity during operation indicated that the modification of the feed solution is essential for improved ultrafiltration performance. Addition of pectin to the original endo-pectinase solution led to a significant reduction of the enzyme deactivation: the enzyme activity yield was 90% at a VCF of 1.6 during operation with the static mixer.