Membrane Bioreactors

In this article, membrane bioreactor principles and applications will be discussed. In particular, the properties and applications of bioartificial hybrid membrane systems used in biotechnological and medical fields will be emphasized. In the first part, we focus on general aspects of membrane bioreactors, including some highlights on membrane properties, functions, and transport as well as on kinetics of biocatalysts immobilized in membranes. Afterwards, membrane bioreactors using immobilized biocatalysts such as enzymes, microorganisms, and cells for the production and separation of bioactive pharmaceutical products are discussed. Membrane bioreactors using isolated mammalian cells (i.e., liver cells and pancreatic cells) as bioartificial organs in temporary or continuous substitution of injured organ are illustrated as well. The properties of membranes to be used in these devices are reported including morphological and physicochemical properties that influence their performance. The effect of immobilization on functional stability and activity of biocatalysts, including membrane material and morphology and physicochemical properties of reaction environment, is considered. Submerged membrane bioreactors for wastewater treatment are highlighted. The successful examples of bioreactors running at large scale, of which the authors are aware, are also presented. The development of membrane bioartificial organs, for example, bioartificial pancreas and bioartificial liver, as well as the properties of membranes for these systems are discussed. Particular attention is given to the recent achievements in cytocompatibility and biocompatibility of membranes in bioartificial organs.