Cellulose-based nanofiber membrane functionalized with dye affinity ligand for purification of malate dehydrogenase from Saccharomyces cerevisiae

Cellulose-based nanofibers are a versatile material with broad applications, including wound-healing/dressing biomaterials, food packing, water treatments, sensors, and energy storage materials. In this work, a cellulose acetate (CA) nanofiber membrane obtained from the electrospinning process was hydrolyzed to a regenerated cellulose (RC) nanofiber membrane. The RC nanofiber membrane coupled with Reactive Orange 4 (RO4) as the dye ligand was used in the purification of malate dehydrogenase (MDH) from the disrupted baker’s yeast in a single step. The optimal pH and the immobilized dye density for MDH adsorption were at pH 7.5 and ~ 520 mg dye/g membrane, respectively. The maximum equilibrium binding capacity for MDH was 3985.65 U/g, and the surface reaction was the main rate-limiting step for MDH transport to the nanofiber membrane throughout the adsorption process. The purification of the MDH process was performed by using a membrane contactor (i.d. 25 mm) in a flow system. An elution solution (pH 5) made of 10 mM NADH and 0.1 M NaCl resulted in high efficiency of MDH elution, recording a recovery yield of 89% and a purification factor of 78 folds. Similar performance of MDH purification was obtained using a larger membrane contactor (i.d. 47 mm), thereby proving the linear scalability of the purification process.