Membrane bioreactor applications

Liao, B.Q., Kraemer, J.T., and Bagley, D.M., Anaerobic membrane bioreactors Applications and research directions, Critical Reviews in Environmental Science and Technology, 36 (6), 489-530, 2006. 

A number of pervaporation membrane bioreactor (PVMBR) applications have also been reported [3.3]. These represent a special class of membrane bioreactor applications, which are discussed more extensively in Chapter 4. A number of studies utilizing PVMBR involve esterification reactions. Van der Padt et al. [3.46], for example, studied in a PVMBR the synthesis of triglycerides from glycerol and fatty acids. The reaction is equilibrium limited, and is described as follows ... 

Lioa, B. Q., Kraemes, J. T, Bagley, D. M. Anaerobic membrane bioreactors Applications and research directions. Crit Rev Environ Sci Techn 2006,36,489-530. 

Lin, H., Peng, W., Zhang, M., Che, n.J., Hong, H., Zhang, Y., 2013. A review on anaerobic membrane bioreactors applications, membrane fouling and future perspectives. Desalination 314, 169—188. 

It is expected that in the very near future, the application of closed water loops will show an intensive growth, strongly supported by the further development of separate treatment technologies such as anaerobic treatment, membrane bioreactors, advanced biofilm processes, membrane separation processes, advanced precipitation processes for recovery of nutrients, selective separation processes for recovery of heavy metals, advanced oxidation processes, selective adsorption processes, advanced processes for demineralisation, and physical/chemical processes which can be applied at elevated temperature. 

In the following, a number of integrated reaction-separation systems wiU be discussed, with emphasis on the application of polymeric membranes. As a result, the systems discussed will be Hmited to relatively low temperatures, typically below 120°C. In Section 13.2, appHcations of membranes in chemical synthesis will be described. Subsequently, in Section 13.3 various examples of membrane bioreactors will be discussed. 

Generally, a distinction can be made between membrane bioreactors based on cells performing a desired conversion and processes based on enzymes. In ceU-based processes, bacteria, plant and mammalian cells are used for the production of (fine) chemicals, pharmaceuticals and food additives or for the treatment of waste streams. Enzyme-based membrane bioreactors are typically used for the degradation of natural polymeric materials Hke starch, cellulose or proteins or for the resolution of optically active components in the pharmaceutical, agrochemical, food and chemical industry [50, 51]. In general, only ultrafiltration (UF) or microfiltration (MF)-based processes have been reported and little is known on the application of reverse osmosis (RO) or nanofiltration (NF) in membrane bioreactors. Additionally, membrane contactor systems have been developed, based on micro-porous polyolefin or teflon membranes [52-55]. 

Figure 13.22 Application of a membrane bioreactor to separate chiral drug mixtures...

Principles and Applications of Membrane Bioreactors in Water and Wastewater Treatment, Elsevier, Great Britain. 

Yang, W.B., Cicek, N. and Ilg, J. (2006) State-of-the-art of membrane bioreactors Worldwide research and commercial applications in North America. Journal of Membrane Science, 270, 201-211. 

The possibility of having membrane systems also as tools for a better design of chemical transformation is today becoming attractive and realistic. Catalytic membranes and membrane reactors are the subject of significant research efforts at both academic and industrial levels. For biological applications, synthetic membranes provide an ideal support to catalyst immobilization due to their biomimic capacity enzymes are retained in the reaction side, do not pollute the products and can be continuously reused. The catalytic action of enzymes is extremely efficient, selective and highly stereospecific if compared with chemical catalysts moreover, immobilization procedures have been proven to enhance the enzyme stability. In addition, membrane bioreactors are particularly attractive in terms of eco-compatibility, because they do not require additives, are able to operate at moderate temperature and pressure, and reduce the formation of by-products. 

Applications of whole-cell biocatalytic membrane reactors, in the agro-food industry and in pharmaceutical and biomedical treatments are listed by Giorno and Drioli [3], Frazeres and Cabral [9] have reviewed the most important applications of enzyme membrane reactors such as hydrolysis of macromolecules, biotransformation of lipids, reactions with cofactors, synthesis of peptides, optical resolution of amino acids. Another widespread application of the membrane bioreactor is the wastewater treatment will be discussed in a separate section. 

In recent years, membrane bioreactors, bioreactors combined with membrane separation unit have established themselves as an alternative configuration for traditional bioreactors. The important advantages offered by membrane bioreactors are the several different types of membrane modules, membrane structures, materials commercially available. Membrane bioreactors seem particularly suited to carry out complex enzymatic/microbial reactions and/or to separate, in situ, the product in order to increase the reaction efficiency. The membrane bioreactor is a new generation of the biochemical/chemical reactors that offer a wide variety of applications for producing new chemical compounds, for treatment of wastewater, and so on. 

Giorno, L., De Bartolo, L. and Drioli, E. (2003) Membrane bioreactors for biotechnology and medical applications, in New Insight into Membrane Science and Technology Polymeric and Bifunctional Membranes (eds D. Bhattacharyya and D.A. Butterfield), Elsevier, Chapter 9, Oxford. 

Defiance, L. and Jaffrin, M.Y. (1999) Comparison between filtrations at fixed transmembrane pressure and fixed permeate flux application to a membrane bioreactor used for wastewater treatment. Journal of Membrane Science, 152, 203-210. 

A particular application of membrane bioreactors, patented in 2005 [20], concerns the production of an antitumor substance (paclitaxel). Since a full synthesis of paclitaxel is not possible due to its low yield, a semisynthesis of 10-deacetyl-baccatin... 

One of the first cases of the application of membrane bioreactors in food processes was the production of milk with low lactose content. (3-galactosidase was entrapped into cellulose acetate fibers to carry out the hydrolysis of milk and whey lactose [2] recently the system was improved by the use of microfiltration and by UV irradiation of the enzyme solution to avoid growth of micro-organisms [45]. 

A very interesting field in membrane bioreactors is the production of cyclodextrins or oligosaccharides. In general, they have applications in food pharmaceutical, cosmetic agricultural, and plastics industries as emulsifiers, antioxidant, and stabilizing agents. In the food industry cyclodextrins are employed for the preparation of cholesterol-free products. The use of enzymatic membrane reactors to produce... 

Prazeres DMF, Cabral JMS (1994) Enzymatic membrane bioreactors and their applications. Enzyme Microb Technol 16 738-750... 

There have been numerous studies exploring the concept of membrane reactors. Many of them, however, are related to biotechnological applications where enzymes are used as catalysts in such reactions as saccharification of celluloses and hydrolysis of proteins at relatively low temperatures. Some applications such as production of monoclonal antibodies in a hollow fiber membrane bioreactor have just begun to be commercialized. 

Cicek N. A review of membrane bioreactors and their potential application in the treatment of agricultural wastewater. Can. Biosyst. Eng. 2003 45 1-13. 

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