Bioseparation systems chromatography

Figure 7.2 Elution systems supplied by LKB, Sweden (a) isocratic bioseparation system (b) basic system (c) advanced chromatography system (d) inert system.

At present, the purification by chromatographic processes is the most powerful high-resolution bioseparation technique for many different products from the laboratory to the industrial scale. In this context, continuous simulated moving bed (SMB) systems are of increasing interest for the purification of pharmaceuticals or specialty chemicals (racemic mixtures, proteins, organic acids, etc.).This is particularly due to the typical advantages of SMB-systems, such as reduction of solvent consumption, increase in productivity and purity obtained as well as in investment costs in comparison to conventional batch elution chromatography [1]. 

Muller, W. (1990). Liquid-liquid partition chromatography of biopolymers in aqueous two-phase systems. Bioseparation, 1(3—4), 265-282. 

Garg, N., Galaev, I. Yu., and Mattiasson, B. (1996). Polymer-shielded dye-ligand chromatography of lactate dehydrogenase from porcine muscle in an expanded bed system. Bioseparation 6, 193-199. 

Liquid-liquid partitioning is a convenient and often economical method for bioseparations. L. Gu (personal communication, 1999) has shown that an acetonitrile-water system can be used for separation of proteins. This system partitions into two phases under subzero temperatures with the top phase containing more acetonitrile and water. The low temperature and the presence of water in both phases help reduce protein denaturation. An added advantage is that sample solution can be directly applied to reversed-phase high-performance liquid chromatography (HPLC) for further purification. Aqueous liquid-liquid partitioning is likely to remain an attractive choice for the separation of proteins, and exploration of new systems will continue. 

The remainder of this introductory chapter focuses on downstream processing and bioseparation relevant to the chapters presented in this book. Thus, the following topics are covered multiphase systems, membrane separation, centrifugation and adsorption techniques, electrophoresis, chromatography, and affinity separations. 

An overview chapter by Hamel and Hunter presents the state of the art of research on bioseparations. Extraction processes using biphasic aqueous systems, liquid membranes, reversed-micellar systems, and membrane processes are all being actively studied. Significant advances in these topics, including predictive mathematical models, are presented in the first section. The second section includes several papers on affinity and other interaction techniques that are finding uses in protein purification. In the last section, we offer several reports that delineate advances in isolation and purification processes such as electrophoresis and chromatography. 

Key words smart polymer, bioseparation, affinity precipitation, two-phase systems, membranes, chromatography, adsorbents, catalysts. 

Displacement chromatography has an enormous potential as a preparative bioseparation technique. In many situations from the mg to the kg scale and beyond the displacement chromatography may theoretically be the most practical, the most economic and the most efficient approach to a given separation problem. However, in order to exploit the full potential of displacement chromatography, suitable displacer/stationary phase systems must become available. This chapter is intended as an introduction to our current understanding of the requirements for systematic displacer design. 

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