Scalable fabrication of sulfated silk fibroin nanofibrous membranes for efficient lipase adsorption and recovery

Fabricating adsorptive materials for fast and high efficient adsorption of enzymes is critical to match the great demands for separation and recovery of enzymes used as biocatalysts. However, it has proven extremely challenging. Here, we report a cost-effective strategy to construct the sulfated group surface-functionalized silk fibroin nanofibrous membranes (SS-SFNM) under mild conditions for positively charged Candida rugosa lipase adsorption. The naturally abundant silk is thus reconstructed into nanofibrous membranes with tunable surface functions. Thereby, the resultant SS-SFNM exhibited excellent adsorption performance towards lipase, including a superior adsorption capacity of 148 mg g−1, fast adsorption equilibrium within 3 h and good reversibility. The fabrication of such fascinating silk-based materials may provide new chance into the design and development of multi-functional membranes for various separated applications.