This manuscript focuses on the aspect of a membrane gradostat as an entirely different concept compared to submerged hollow fibre modules. The use of membrane bioreactor (MBR) technology is rapidly advancing in the wastewater treatment industries. However, this is not the case in the biopharmaceutical manufacturing industries. The MGR has shown great potential and versatility in terms of industrial applications. It can be used in both wastewater treatment and biopharmaceutical manufacturing using different modes of operation to meet any predetermined process requirements. The MGR concept uses capillary membranes, which contain microvoids in the substructure to immobilise microbial cells or enzymes, depending on the bioreactor’s application. Operational requirements of the MGR and its commercial potential are discussed from a bioprocess engineering perspective.