A reactor 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, said reactor comprising a cylindrical reactor vessel (120, 230) having a first end part, a second end part, and an inner wall between these parts, in which reactor vessel a transformation device has been mounted, said transformation device comprising a flow distributor (102, 212) 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 centre 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 member(s), at least one fluid medium outlet permeable for said fluid medium but impermeable for solid reaction member(s), said outlet(s) being located on said peripheral wall, a driving shaft (114, 226) located on said first surface for enabling rotation or oscillation of the flow distributor (102, 212), and at least one confinement wherein said solid reaction member(s) can be trapped and said transformation is performed; and a means (116, 214) for rotating and/or oscillating the device; wherein said inner wall of the reactor vessel comprises means (124, 126, 128, 140, 232) for enhancing the fluidic shear stress in any of the two rotary directions along said inner wall between said first end part and said second end part, wherein said means (124, 126, 128, 140, 232) are formed in the inner wall of the reactor vessel (120, 230), characterized in that means (124, 126, 128, 140, 232) for enhancing the fluidic shear stress are hollow structures (124, 126, 128, 140) in said wall, said hollow structures extending in a direction from said first end part to said second end part, said hollow structures (124, 126, 128, 140) having open ends above and below said flow distributor (102, 212) and a through-going channel therebetween, thereby facilitating communication between the fluidic medium above and below the flow distributor (102, 212). a cylindrical reactor vessel (120, 230) having a first end part, a second end part, and an inner wall between these parts, in which reactor vessel a transformation device has been mounted, said transformation device comprising a flow distributor (102, 212) 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 centre 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 member(s), at least one fluid medium outlet permeable for said fluid medium but impermeable for solid reaction member(s), said outlet(s) being located on said peripheral wall, a driving shaft (114, 226) located on said first surface for enabling rotation or oscillation of the flow distributor (102, 212), and at least one confinement wherein said solid reaction member(s) can be trapped and said transformation is performed; and a means (116, 214) for rotating and/or oscillating the device; wherein a flow distributor (102, 212) 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 centre 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 member(s), at least one fluid medium outlet permeable for said fluid medium but impermeable for solid reaction member(s), said outlet(s) being located on said peripheral wall, a driving shaft (114, 226) located on said first surface for enabling rotation or oscillation of the flow distributor (102, 212), and at least one confinement wherein said solid reaction member(s) can be trapped and said transformation is performed; and a means (116, 214) for rotating and/or oscillating the device; wherein said inner wall of the reactor vessel comprises means (124, 126, 128, 140, 232) for enhancing the fluidic shear stress in any of the two rotary directions along said inner wall between said first end part and said second end part, wherein said means (124, 126, 128, 140, 232) are formed in the inner wall of the reactor vessel (120, 230), characterized in that means (124, 126, 128, 140, 232) for enhancing the fluidic shear stress are hollow structures (124, 126, 128, 140) in said wall, said hollow structures extending in a direction from said first end part to said second end part, said hollow structures (124, 126, 128, 140) having open ends above and below said flow distributor (102, 212) and a through-going channel therebetween, thereby facilitating communication between the fluidic medium above and below the flow distributor (102, 212).