@article{article_1683104, title={Immobilization and Characterization of D-Lactate Dehydrogenase onto 3-aminopropyl Silica Gel Support}, journal={Journal of the Institute of Science and Technology}, volume={15}, pages={1411–1422}, year={2025}, DOI={10.21597/jist.1683104}, author={Varan, Nazlı Ece and Tukel, Sevde Seyhan}, keywords={D-Laktat dehidrogenaz, immobilizasyon, 3-aminopropil silika jel}, abstract={In this study, D-lactate dehydrogenase (D-LDH) from Leuconostoc mesenteroides was covalently immobilized onto 3-aminopropyl-functionalized silica gel using glutaraldehyde as a bifunctional crosslinker, with the aim of developing a catalytically active and thermally stable biocatalyst for D-lactic acid production. The immobilization protocol achieved an efficiency of 86% using 1 mg/mL of enzyme and 0.250 g of support material. Comparative biochemical characterization of both free and immobilized D-LDH was performed, assessing optimal pH and temperature, thermal stability and kinetic parameters. The immobilized enzyme preparation exhibited an optimal pH of 6.5 and a temperature optimum of 45 °C. These values corresponded to 7.0 and 37 °C for the free enzyme. Kinetic analysis revealed a Michaelis constant (Km) of 0.37 mM and maximum velocity (Vmax) of 86.9 U/mg protein for the free enzyme, whereas the immobilized enzyme displayed a significantly reduced Km of 0.08 mM and a lower Vmax of 19.2 U/mg protein, indicating increased substrate affinity but reduced catalytic turnover. Thermal stability assays demonstrated enhanced resistance of the immobilized D-LDH to elevated temperatures. Furthermore, reuse studies in a batch reactor showed that the immobilized enzyme preserved 38% of its original activity after 10 successive uses, underscoring its potential for repeated use in biotechnological applications.}, number={4}, publisher={Iğdır Üniversitesi}, organization={Bu çalışma Çukurova Üniversitesi Araştırma Projeleri Birimi tarafından desteklenmiştir.}