Bioconversion system, integrated

This paper is meant to be an overview of the developments in the use of aqueous two-phase systems in the recovery of products of fermentation, and also purification of proteins and other biomolecules. It also touches upon the means to improve the economics of the process to make it industrially feasible. It has been realized that the closer integration of bioconversion processes with downstream technology is essential for quicker and more economical enrichment of the product. Initial efforts have already been taken in this direction, some of which are discussed here. 

When reactions are reversible or products unstable, it is attractive to int ate recovery and (bio-)reaction, that is in situ product removal (ISPR). Compatibility of bioconversion and separation conditions is a key issue in ISPR. It will be demonstrated in a later section that constraints in an integrated system are completely different from those in the individual, non-int ated process steps. It may also be attractive to combine separation steps. A well-known example is crystallization with a withdrawal of coarse crystals (integration of molecular and mechanical separations). Often, an optimal integrated system will operate imder conditions that are not equal to those of the individual and non-integrated conversion and separation steps. This is process integration at the level of unit operations. 

A further development aimed at increasing process integration lies in the use of three-phase membrane reactors, which were developed mainly for the recovery of organic acids [208]. In these systems, the aqueous bioconversion medium. 

In Part I a selection of the types of membrane reactor is presented, together with chapters on the integration of membrane reactors with current industrial processes. To summarize, in Chapter 1 (Calabro) membrane bioreactors are described from an engineering point of view, together with a straightforward description and simulation, with a simple mathematical approach, of the most important configurations and processes in which they are involved. Basic principles of bioconversion, bioreactors and biocatalysis with immobilized biocatalysts are also presented. For all the cited systems the most significant parameters are defined in order to estimate their performances. The best approaches for the preparation of... 

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