Development of a novel disposable filter bag for separation of biomolecules with functionalized magnetic particles

The integration of disposable magnetic filters in combination with functionalized magnetic particles represents a fast and cost-effective alternative for enzyme purification in comparison to solid/liquid separation by means of centrifugation followed by chromatographic purification. The main advantage of the particle-based process is the solid/solid/liquid separation in one step combined with disposable equipment. Furthermore this combination provides the possibility to also process biocatalytic reactions in cell-containing media into disposable equipment with preimmobilized enzymes onto the magnetic particles. The focus of the presented study is on the design and performance of a disposable filtration unit consisting of a plastic bag with an inlet and outlet and a stainless steel filter matrix. During magnetic separation, the magnetic particles selectively retard at the filter matrix due to the magnetic force, which counteracts the drag force. It was found that the length of a lengthwise aligned filter matrix should be longer than the magnetic pole surfaces in fluid flow direction. Hereby, a filtration capacity of 5.6 g magnetic particles was measured with a loss of below 0.5%. Introducing a two-phase flow optimizes the cleaning of the bag after a magnetic filtration. The procedure offered a high cleaning efficiency. Herewith, the cleaned filter unit could be discarded with minimum losses of product and magnet particles.