Design and development of tri-layered functionalized chitin nanocrystals (ChNC) based enzyme membrane system for antifouling and selective production of oligosaccahrides

Abstract

In this study, biobased green polymer, i.e. high surface area (370m2/g) chitin nanocrystals (ChNC) were isolated and functionalized via acylation of antifoulents (palmitic and stearic acid) were and used as catalyst for hydrolysis. To limite enzyme activation, dextranase was immobilized via entrapment followed by the covalent crosslinking. At this sstage, a modern design of EMR is introduced having tri-layered membrane integration. On top, long pine fiber (LPF) porus membrane was produced. It was used to hold the enzyme. It impacted the hydrolysis of polysaccharides without halt. In the middle, functionalized ChNC (ChNC-PA/SA-E) membrane was used for the catalysis of polysaccharides, and in the bottom, microfibrillated cellulosic (MFC) separation membrane was used for the selective separation of product (oligosaccharides) from mixture of low and high Mw oligosaccharides. The pore-size distribution of produced membtranes was in the range of 0.1 to 30 μm and the densification was in the order of ChNC-PA/SA-E > MFC separation membrane>LPF porous membrane. Very high water permeability i.e., ∼2500 L.h−1.m−2 for LPF porous support was followed by pristine MFC (∼600 L.h−1.m−2). The functionalized ChNC loaded membranes have low water permeability (<500 L.h−1.m−2). In addition, increased contact angle (5–6 folds) and BSA rejection (3 folds) after grafting of PA and SA compared to prisine MFC separation was recorded.