Biocatalysis process

The use of ionic liquids (ILs) to replace organic or aqueous solvents in biocatalysis processes has recently gained much attention and great progress has been accomplished in this area lipase-catalyzed reactions in an IL solvent system have now been established and several examples of biotransformation in this novel reaction medium have also been reported. Recent developments in the application of ILs as solvents in enzymatic reactions are reviewed. 

Canyon identify differences in the technology employed in biocatalysis processes depending on whether the process is designed to prodnct a new prodnct, or an improved version of a pre-existing product ... 

Figure 30.12 represents a cell factory model to produce several categories of products via fermentation and biocatalysis processes. Industrial-scale manufacturing aspects such as uses, synthesis methods, and costs of some of these products are reviewed below as well as in Chapter 32. 

There are a number of challenges to the successful development of a commercial biocatalysis process. Most of these challenges can be addressed at the outset by properly setting up a screen in order to identify a novel catalyst which has the properties necessary to carry out a reaction that can be scaled-up. The most critical challenges include the following. 

One of our activities is to develop new Hbraries of enzymes for certain classes of chemical reactions so that the speed of developing a new biocatalysis process is increased, thus expanding the options at the top of the diagram. 

With the access to diverse and stable biocatalysts, more and more conventional chemical processes (first generation) in pharmaceutical manufacturing have been replaced by second-generation biocatalysis processes with substantial impact on the pharmaceutical industry. In this chapter, some commonly used biocatalytic reactions for chiral preparation, including hydrolytic reactions, acyl and glycosyl transfer reactions, asymmetric reduction/ oxidation reactions, and asymmetric formation of C-C bonds, are introduced and exemplified by the research achievements developed by the authors laboratory as well as other research groups. Some of the bioprocesses described herein have been successfully applied on pilot or even industrial scale. ... 

Key words membrane bioreactors, biocatalysis, process modelling,... 

Shu-Jen C. Strain improvement for fermentation and biocatalysis processes by genetic engineering technology.J Ind Microbiol Biotechnol 2004 31 99-108. 

Dennewalda, D., Pitnerb, W.-R., and Weuster-Botza, D. (2011) Recyding of the ionic liquid phase in process integrated biphasic whole-cell biocatalysis. Process Biochem., 46,1132—1137. 

Cellulases show higher affinity to molecules of fines fraction than to long fibers. It protects them from significant damage in biocatalysis process. The enzymes hydrolyze partially fines contained in the pulp, improving their drainability on paper machine. This... 

The term biotransformation or biocatalysis is used for processes in which a starting material (precursor) is converted into the desired product in just one step. This can be done by use either of whole cells or of (partially) purified enzymes. Product examples range from bulk chemicals (such as acrylamide) to fine chemicals and chiral synthons (chiral amines or alcohols, for example). There are several books and reviews dealing with the use of bio transformations either at laboratory or at industrial scales [1, 10-13]. 

Recently, recombinant biocatalysts obtained using Escherichia coli cells were designed for this process. The overexpression of all enzymes required for the process, namely, hydantoinase, carbamoylase, and hydantoin racemase from Arthrobacter sp. DSM 9771 was achieved. These cells were used for production of a-amino acids at the concentration of above 50 g 1 dry cell weight [37]. This is an excellent example presenting the power of biocatalysis with respect to classical catalysis, since a simultaneous use of three different biocatalysts originated from one microorganism can be easily achieved. 

These perspectives allow us to conclude that the constant rise of importance of biocatalysis in industrial processes is secured for years to come, and is limited only by further recognition from industrial society. 

Another advantage of biocatalysis is that chemo-, regio-, and stereoselectivities are attainable that are difficult or impossible to achieve by chemical means. A pertinent example is the production of the artificial sweetener, aspartame, which has become somewhat of an industrial commodity. The enzymatic process (Fig. 2.31), operated by the Holland Sweetener Company (a joint venture of DSM and Tosoh), is completely regio- and enantiospecific (Oyama, 1992). 

Bruggink (1996) has given an account of how the production of cefalexin, which is the largest cephalosporin in the market, can be converted from a ten-step process based on benzaldehyde and penicillin into a six-step process where biocatalysis is involved in three steps. The wastewater stream, containing 30-40 kg of unwanted materials in the conventional process, has been substantially reduced. Similarly, Van Loon et al. (1996) have given details of fermentation processes for cleaner and cheaper compared to the process practised so far. 

Boundary membranes play a key role in the cells of all contemporary organisms, and simple models of membrane function are therefore of considerable interest. The interface of two immiscible liquids has been widely used for this purpose. For example, the fundamental processes of photosynthesis, biocatalysis, membrane fusion and interactions of cells, ion pumping, and electron transport have all been investigated in such interfacial systems. 

In 1982, Lilly [21] reviewed the first two-liquid phase biocatalysis. In 1987 and 1992, Lilly s group [39,40] published reviews dealing with process engineering of biphasic bioreactors. In 1993, Van Sonsbeek et al. [41] gave an overview on biocatalysis in different biphasic... 

General rules need to be adapted for different biotransformation processes because they are not based on the specific study of all systems. Biocatalysis conditions are optimized when carrying out experiments designed to increase knowledge of the process. 

Woodley, J.M. (2008) New opportunities for biocatalysis making pharmaceutical processes greener. Trends in Biotechnology, 26 (6), 321-327. 

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