IMMOBILIZATION OF XYLANASE ON MAGNETIC NANOPARTICLES MODIFIED WITH POLYETHYLENEIMINE AND ITS APPLICATION IN XYLO-OLIGOSACCHARIDES SYNTHESIS

Abstract

A food-grade bacterial xylanase enzyme preparation, ROHALASE® SEP-VISCO, was immobilized by adsorption onto polyethyleneimine (PEI) functionalized magnetic nanoparticles (MNPs). This process resulted in nanobiocatalysts with optimal characteristics. Subsequently, this nanobiocatalyst was employed to produce xylo-oligosaccharides (XOS). In the past decade, magnetic nanoparticles (MNPs) have gained significant interest, finding diverse applications in biomedicine, biosensor production, food processing, catalysis, agriculture, and environmental processes. MNPs have proven highly effective for enzyme immobilization because of their unique and distinguished properties such as high specific surface area, biocompatibility, and magnetic characteristics. Magnetic characteristics facilitate the easy removal of MNPs from reaction mixtures, allowing for their efficient reuse. The functionalization of MNPs through with the cationic polymer PEI can further augment their ability for enzyme attachment. Generally, xylanases hydrolyses β-1,4-glycosidic linkages present in xylan which is a major component of the hemicellulosic fraction in the plant cell walls. Furthermore, xylanases can produce XOS composed of xylose units linked by β-1,4-xylosidic bonds. XOS have stimulatory effects on the selective growth of human intestinal microbiota and are frequently defined as prebiotics. In the present work, the xylanase immobilization efficiency on MNPs-PEI is between 100 and 43 % within the wide range of xylanase concentrations (400-2400 mg/g of support). Free and immobilized xylanase showed maximal catalytic activity at pH 6.0 and 60°C in reaction with commercial birchwood xylan (concentration of 1 % w/v). The maximum activity of 1675 IU/g of support was achieved when immobilization was performed at initial enzyme concentration of 1250 mg/g of support during 2 h. Since this immobilized preparation exhibited the activity immobilization yield of 80 % and specific activity of 2.1 mg of proteins/g of support, it has been applied in reaction of XOS synthesis. The MNPsPEI-xylanase was found to produce high yield of XOS from birchwood xylan, indicating its potential for utilization in feed and food formulations.