Bacterial cellulose nanofibers for dye-affinity adsorption of recombinant human interferon-α

The bacterial cellulose (BC) nanofibers were produced by Acetobacter xylinum in the Hestrin-Schramm medium in a static condition for 14 days. Then, Cibacron Blue F3GA (CB) was covalently attached onto the BC nanofibers for affinity adsorption of recombinant interferon-α (rHuIFN-α). The CB content of the BC nanofibers was 178 μmol/g. The specific surface area of the BC nanofibers was determined to be 914 m²/g. rHuIFN-α adsorption studies were performed by batch system. The non-specific adsorption of rHuIFN-α on the BC nanofibers was very low (2.1 mg/g polymer). CB attachment onto the BC nanofibers significantly increased the rHuIFN-α adsorption (1620 mg/g). The maximum rHuIFN-α adsorption was observed at pH 6.0. The rHuIFN-α adsorption capacity decreased drastically with an increase of the aqueous phase concentration of sodium chloride. The elution studies were performed by adding 1 M NaCl to the rHuIFN-α solutions in which adsorption equilibria had been reached. The eluted rHuIFN-α had a specific activity in the range of of 3.32-3.45 x 10⁸ IU/mg as inhibition of the cytopathic effect of MDBK cells. In order to determine the effects of adsorption conditions on possible conformational changes of rHuIFN-α structure, fluorescence spectrophotometry was employed. We resulted that the BC-CB nanofibers can be applied for rHuIFN-α adsorption without causing any significant conformational changes. The elution results showed that the binding of rHuIFN-α to the BC-CB nanofibers was reversible. This study demonstrated that the BC nanofibers has a potential for affinity carrier applications in protein adsorption systems.