Electrospun Polycaprolactone–Chitosan Nanofiber Scaffolds for Covalent Immobilization of Xylanase: Structural Characterization and Enzyme Performance

Xylanases are critical enzymes that release xylose and its derivatives through the hydrolysis of xylan, the primary component of hemicellulose, and are of great importance to many industrial fields. However, there are several factors that limit their use in free form. Enzyme immobilization stands out as an important strategy to overcome these limitations. In this study, PCL/CHI nanofibers were synthesized by electrospinning, and an innovative nanocarrier platform was developed for Xylanase immobilization. A solution containing 10% PCL and 0.5% CHI was converted into nanofibers by electrospinning under optimized conditions (22 kV, 1 mL/h, 18 cm) and then cross-linked with glutaraldehyde to make them suitable for enzyme immobilization. SEM, EDX, XRD, and FT-IR analyses confirmed the morphological and structural integrity of the nanofibers. When comparing free and immobilized xylenese, the optimum temperature was determined as 50°C for both forms, while the optimum pH was determined as 6 for the free form and 5 for the immobilized form. The decrease in activation energy from 21.46 kJ/mol to 1.17 kJ/mol in the immobilized form indicated that the reaction occurred with a lower energy barrier. Furthermore, the decrease in Km value revealed that immobilization enhanced enzyme-substrate interaction, while reusability tests showed that the immobilized enzyme retained 45% of its initial activity after five cycles. The fact that the immobilized form maintained its high catalytic performance in the presence of metal ions highlights the system's potential for adaptation to industrial conditions. In conclusion, this developed platform has been demonstrated to be a promising approach for sustainable and economical solutions in enzyme technologies.