원문정보
초록
영어
Acetyl xylan esterase (AXE) from Aspergillus ficcum which mediated the production of peraceticacid(PAA) was covalentlyimmobilized with magnetic Fe3O4–chitosan(Fe3O4–CS) nanoparticles using glutaraldehyde. The magnetic Fe3O4–CS nanoparticles were prepared by electro static adsorption of chitosan onto the surface of Fe3O4 nanoparticles. The Fe3O4–CSnanoparticles were characterized by FESEM, FTIR and XRD. The immobilization was optimized using Response Surface Methodology (RSM) by examining immobilization cross-linking time, enzyme concentration, and glutaraldehyde (GA) concentration. Based on the experimental values the predicted variables for the maximum immobilization of AXE in terms of specific activity (0.042) were found to be 13.65 μg of AXE protein and 0.265 % of GA concentrations, where the optimum cross-linking time of 11.33 hr. The immobilized AXE onto Fe3O4–CSnanoparticlesshows better stability at thermal and pH ranges than soluble free AXE. It was subjected to PAA production condition, where it retains over 78% of its original activity after eight repeated cyclic usage.