A reactor arrangement for performing, by means of at least one solid reaction member(s), a biological or chemical transformation, or physical or chemical trapping from, or release of agents to, a fluidic media in a continuous process or in a batch process, wherein said reactor arrangement comprises a main reactor and at least one auxiliary reactor, wherein said auxiliary reactor comprises a cylindrical reaction vessel having a first end part, a second end part, and an outer wall comprising an outer surface and an inner surface between these parts, in which auxiliary reactor a transformation device has been mounted, said transformation device comprising a flow distributor having an essentially cylindrical shape, a first essentially flat surface, a second essentially flat surface, and a peripheral wall having an essentially circular cross-section, at least one fluid medium inlet located in vicinity of the center of said first and/or second surface, said inlet being adapted for receiving fluid medium and optionally being adapted for receiving initially suspended solid reaction members, at least one fluid medium outlet permeable for said fluid medium but impermeable for solid reaction members, said outlet(s) being located on said peripheral wall, a driving shaft located on said first surface for enabling rotation or oscillation of the flow distributor, and at least one confinement wherein said solid reaction member(s) can be trapped and said transformation is performed; and a means for rotating and/or oscillating the device; wherein said auxiliary reactor further comprises a feed conduit which, via an inlet port of the auxiliary reactor, is connected to an outlet port of said main reactor; and a return conduit which, via an outlet port of the auxiliary reactor, is connected to an inlet port of said main reactor, and wherein the main reactor is larger than the auxiliary reactor. said auxiliary reactor comprises a cylindrical reaction vessel having a first end part, a second end part, and an outer wall comprising an outer surface and an inner surface between these parts, in which auxiliary reactor a transformation device has been mounted, said transformation device comprising a flow distributor having an essentially cylindrical shape, a first essentially flat surface, a second essentially flat surface, and a peripheral wall having an essentially circular cross-section, at least one fluid medium inlet located in vicinity of the center of said first and/or second surface, said inlet being adapted for receiving fluid medium and optionally being adapted for receiving initially suspended solid reaction members, at least one fluid medium outlet permeable for said fluid medium but impermeable for solid reaction members, said outlet(s) being located on said peripheral wall, a driving shaft located on said first surface for enabling rotation or oscillation of the flow distributor, and at least one confinement wherein said solid reaction member(s) can be trapped and said transformation is performed; and a means for rotating and/or oscillating the device; wherein said auxiliary reactor further comprises a feed conduit which, via an inlet port of the auxiliary reactor, is connected to an outlet port of said main reactor; and a return conduit which, via an outlet port of the auxiliary reactor, is connected to an inlet port of said main reactor, and wherein the main reactor is larger than the auxiliary reactor.