Enzymatic conversion of rifamycin B in a rotating packed disk reactor

Abstract

The biological conversion of rifamycin B to rifamycin S was attempted using immobilized rifamycin B oxidase in a rotating packed disk reactor (RPDR). Humicola sp. (ATCC 20620) was treated with acetone and the cell powder was immobilized with cellulose acetate. The three phase reaction involving oxygen, substrate, and the immobilized enzyme beads was done in the RPDR. The physical strength of the immobilized enzyme beads was very good and was suitable as packing material in RPDR. The optimum submergence in the RPDR was 0.5 and the rotating speed of the disk did not affect the conversion very much. In continuous operation as the residence time increased, the conversion of rifamycin B increased, but the productivity decreased.