RESUMO
A thermally stable and alkalophilic xylanase, XynCDBFV, from Neocallimastix patriciarum was overexpressed in Escherichia coli as a recombinant protein fused to the N-terminus of oleosin, a unique structural protein of seed oil bodies. As a result of the reconstitution of the artificial oil bodies (AOBs), the immobilization of active xylanase was accomplished. Response surface methodology (RSM) was employed for the optimization of the immobilized xylanase activity. The central composite design (CCD) and regression analysis methods were effective for determination of optimized temperature and pH conditions for the AOB-immobilized XynCDBFV. The optimal condition for the highest immobilized xylanase activity (3.93IU/mg of total protein) was observed at 59 degrees C and pH 6.0. Further, AOB-immobilized XynCDBFV retained 50% of its maximal activity after 120min at 60 degrees C, and it could be easily and simply recovered from the surface of the solution by brief centrifugation, and could be reused eight times while retaining more than 60% of its activity. These results proved it is a simple and effective method for direct immobilization of xylanases.