The Concept and Practical Challenges of Membrane Gradostat Reactors

Developing a new technology from a theoretical concept to its industrial application is generally a long and burdensome procedure. The membrane gradostat reactor (MGR) – which was invented for the continuous production of secondary metabolites – is now at the initial stage of this process. Therefore, even though it was patented a quarter of a century ago, relatively few studies have been published concerning this device. In this opinion article, the structure of the MGR, transport mechanisms through the biofilm and membrane, methods and challenges of inoculation as well as the aspects determining the structure of a suitable membrane and species will be overviewed. The findings are based on the observations from other publications as well as the own experiences of the authors.