Membrane bioreactors downstream processing

In the development of cell or enzyme-based processes, many process configurations exist, including batch, fed batch and continuous operation. In general, the conversion and the separation processes (downstream processing) are regarded as separate units, and most industrial processes are based on this approach. In the last decades, however, more attention is paid to the integration of conversion and separation, leading to the development of membrane bioreactors [49, 50], and some of these concepts have reached an industrial scale. The membranes used for this type of reactors are almost exclusively polymeric, as temperatures seldomly exceed 100 °C for obvious reasons. 

In the pharmaceutical field, on the one hand, the application of a membrane within the bioreactor greatly improves the concentration and purity downstream with respect to the compound of interest, thus reducing the downstream processing costs on the other hand, MBRs show higher conversion rates with respect to plain bioreactors when a product inhibition or a reversible reaction occurs. In this case, the product removal increases the yield of the reactive process, even overreaching the thermodynamic threshold of the equilibrium conversion. 

Abstract In this chapter, membrane bioreactors are described from an economic point of view. Economic analysis is a crucial stage in plant design, project and control and also requires an evaluation of the research, development and commercialization of the products and bioproducts. Such an analysis is focused here on membrane bioreactors and reactors, also taking into account the separation units such as micro-, ultra- and nano-flltration units that might be used as a downstream process or as pretreatment steps. The most important rules and parameters are first introduced. Some examples of application and case studies are also reported. 

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