The application of novel magnetically coupled mixer drives in bioreactors of up to 15 m3

•The design of the novel magnetically coupled mixer drive is demonstrated.•Magnetic field simulations were performed for two magnetic drive scales.•The magnetic mixers were built according to the simulated designs.•Magnetic mixer performance was evaluated in terms of maximal torque and power input.•The magnetic drive was applied during K. marxianus cultivations in 15 m3 bioreactor. We introduce a novel magnetically coupled mixer drive for biotechnological, pharmaceutical and chemical applications requiring high-grade aseptic conditions. The proposed design enables its application in larger volume bioreactors compared to traditional magnetic drives, due to a possibility of introducing higher power quantities per individual rotor, while ensuring higher mixing intensity. In the following study, we provide information on the design aspects of the novel magnetic drive and demonstrate the principles behind both theoretical and experimental maximal torque and other key working parameter evaluation. Based on the mentioned principles, magnetic mixer drives were developed for laboratory (5 dm3) and pilot-scale (15 m3) bioreactors. The specific power inputs relative to the agitation rates for the mentioned mixers were experimentally determined in water for two impeller types: six-bladed Rushton and three-bladed Pitched-blade turbines. The performance of the novel magnetic drive was evaluated during Kluyveromyces marxianus cultivations utilizing whey (a well known byproduct of the dairy industry) as the main substrate source in the 15 m3 bioreactor. The obtained results show that the novel magnetic drive can be successfully applied in 15 m3 bioreactors, while providing sufficient mixing of the cultivation broth for biomass growth.