Design of chitosan/PSf self‐assembly membrane to mitigate fouling and enhance performance in trypsin separation

BACKGROUND: Membrane fouling in downstream processing has become a major obstacle in enzyme production. The use of a membrane with high surface hydrophilicity may be an acceptable way to overcome this problem. In this study, the effects of dip time on chitosan incorporation were investigated to produce a low fouling ultrafiltration membrane for trypsin separation. RESULT: Pristine ultrafiltration membrane with a polymer concentration of 15% was developed via phase inversion. Membrane surface modification was performed using chitosan solution with different dip times. Membranes with a 60‐min dip time provided optimum trypsin transmission (about 91.8%). Such membranes have a high permeability coefficient (71 L m^?2 h^?1) and good porosity (about 89.6%). The hydrophilicity of this modified membrane was also improved by 50% compared with the native membrane, and its flux recovery was about 89.8%. The successful assembly of chitosan onto the membrane's surface was ascertained by ATR‐FTIR and X‐ray diffractometry (XRD). The morphology of this membrane was significantly different from that of native membrane. CONCLUSION: The experimental results show that membrane dip time exerts a significant influence on the self‐assembly of chitosan particles onto the membrane's surface, and this process can be used to produce a potentially low‐fouling UF membrane for trypsin separation. Copyright © 2012 Society of Chemical Industry