A method is provided which introduces a first stream proximate a plurality of fibers positioned within a fiber conduit apparatus such that the first stream constitutes a phase substantially constrained to the surface of the fibers. The method further introduces an enzyme into the apparatus and introduces a second stream into the apparatus that is in contact with and is substantially immiscible with the first stream. The first stream, the enzyme and the second stream are introduced into the apparatus such that the enzyme interacts with a species from one of the first and second streams and compositions of the first and second streams are altered. An apparatus is provided which includes a plurality of fibers positioned longitudinally within a conduit between two fluid inlets and a fluid outlet, wherein the plurality of fibers have one or more enzymes immobilized thereon.