In this study, a series of experiments was conduct-ed to demonstrate the feasibility of continuous production of penicillin antibiotic using a three-phase magneto airlift fermenter with immobilized Penicillium chrysogenum. The fermentation processes were carried out in a 2.4-L external loop airlift utilizing a transverse magnetic field. It was found that the application of the magnetic field to a bed of ferromagnetic beads affects both the hydrodynamics of the reactor and the rate of the bioconversion process occurring inside it. One hundred hours after startup, the maximum penicillin concentration increased 48% as the magnetic field intensity ir;creased from 0 to 35 mT, owing to the increased residence time of the substrate in the riser and the positive effect of the magnetic field on the effective fluid-solid interfacial area. In addition, the detached biomass concentration in the liquid phase was found to be only 5% of the immobilized biomass, owing to low shear levels and the absence of friction among the solid-phase particles.