Bacterial cellulose nanofibrous aerogels grafted with citric acid for absorption and separation of protein

The design and construction of high-performance protein absorbents are of great significance for obtaining highly purified proteins in the field of biotechnology and more. In this study, the highly carboxylated absorption media were fabricated for selective absorption of positively charged proteins by using bacterial cellulose (BC) nanofibrous aerogel (NFA) as a substrate material in concert with citric acid (CA). The obtained BC/CA NFAs exhibited highly interconnected open porous structure, surface hydrophilicity, large specific surface area (14.2 m 2 /g), good elasticity and compression fatigue resistance. BC/CA NFAs displayed a high lysozyme absorption capacity of 868.9 mg/g and fast equilibrium within 2.5 h. A dynamic lysozyme absorption capacity of 655.35 mg/g was achieved under the drive of gravity, meeting the demands of actual applications. Furthermore, BC/CA NFAs exhibited unique absorption selectivity performance, good reusability, as well as acid and alkaline resistance. A successful scale-up of such environmental friendliness, low cost and good reproducibility absorbents could provide a new perspective to develop next generation three-dimensional chromatographic media for substantial bio-separation applications. Graphical abstract