Biocatalysis importance

Through this book, I hope to introduce the novelty and future directions in biocatalysis. Importantly, I wish to contribute to conserve and beautify the natural environment by editing the book, showing the power of enzymes, treasure from Mother Nature, to catalyze the necessary reaction for mankind in an environmental-friendly manner. 

Biocatalysis has emerged as an important tool for the enantioselective synthesis of chiral pharmaceutical intermediates and several review articles have been published in recent years [133-137]. For example, quinuclidinol is a common pharmacophore of neuromodulators acting on muscarinic receptors (Figure 6.50). (JJ)-Quinudidin-3-ol was prepared via Aspergillus melleus protease-mediated enantioselective hydrolysis of the racemic butyrate [54,138]. Calcium hydroxide served as a scavenger of butyric acid to prevent enzyme inhibition and the unwanted (R) enantiomer was racemized over Raney Co under hydrogen for recycling. 

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. 

Biocatalysis refers to catalysis by enzymes. The enzyme may be introduced into the reaction in a purified isolated form or as a whole-cell micro-organism. Enzymes are highly complex proteins, typically made up of 100 to 400 amino acid units. The catalytic properties of an enzyme depend on the actual sequence of amino acids, which also determines its three-dimensional structure. In this respect the location of cysteine groups is particularly important since these form stable disulfide linkages, which hold the structure in place. This three-dimensional structure, whilst not directly involved in the catalysis, plays an important role by holding the active site or sites on the enzyme in the correct orientation to act as a catalyst. Some important aspects of enzyme catalysis, relevant to green chemistry, are summarized in Table 4.3. 

However, the reactions were not enantioselective ones, though the most important aspect of the biocatalysis reaction should be in the enantioselective reaction. We and KragF independently reported the first enantioselective lipase-catalyzed reaction in February-March 2001. Since lipase was anchored by the IL solvent and remained in it after the extraction work-up of the product, we succeeded in demonstrating that recyclable use of the lipase in the [bmim][PFg] solvent system was possible (Fig. 2). ... 

Important topics in biocatalysis for organic synthesis are described in this book, for experts and non-experts. Especially, the book focuses on those reactions that are under development now and will be more significant in the future. Therefore, each chapter describing a specific theme summarizes not only the present state but also the direction of the research. The prospects and dreams that will become possible, using biocatalysis, in the future to construct a sustainable society are also included. 

This chapter will consider some of the most interesting of current approaches to the evolution of enzyme mimics, in the context of continuing dramatic progress in protein and nucleotide engineering. There are excellent practical as well as intellectual reasons for the broad interest in this topic. Catalysis is a major preoccupation of the chemical industry if the application of the principles of biocatalysis can lead to robust and efficient catalysts tailor-made for reactions of economic importance the area will become even more a focus of intense activity and investment. 

It should be noted that the dynamics studied by fluorescence methods is the dynamics of relaxation and fluctuations of the electric field. Dipole-orientational processes may be directly related to biological functions of proteins, in particular, charge transfer in biocatalysis and ionic transport. One may postulate that, irrespective of the origin of the charge balance disturbance, the protein molecule responds to these changes in the same way, in accordance with its dynamic properties. If the dynamics of dipolar and charged groups in proteins does play an important role in protein functions, then fluorescence spectroscopy will afford ample opportunities for its direct study. 

It is interesting to speculate on the development of such a focused biocatalysis-based chemical industry. It is Ukely that at least one more decade will pass before a significant biocatalysis-driven company emerges. A very important attribute of such a company will be the ability of management not to be side-tracked by nonissues, examples of which are ... 

The field of biocatalysis in organic media is now of considerable industrial importance, enjoying widespread application, particularly in the preparation of enantiopure intermediates. 

Biological fuel cells have a long history in the literature,but in recent years, they have come to prominence as more conventional fuel cell technologies have approached mass-market acceptance. Driving the recent ascendance of biofuel cells are the aspects of biocatalysis that are unmatched by conventional low-temperature oxidation—reduction catalysts, namely, activity at near-room temperatures and neutral pH and, more importantly, selective catalytic activity. 

In order to provide dTDP-deoxy sugars by combinatorial biocatalysis we have utiHzed the enzymes for the dTDP- 3-L-rhamnose pathway. The successful combination of pathway enzymes with optimized enzyme productivities (amount of product per unit of enzyme) needs a concise kinetic and inhibition analysis. Scheme 5.1 depicts the biosynthetic pathway of dTDP- 3-L-rhamnose with important km and Ki constants. The enzymes RmlA and RmlB are highly controlled by the intermediate, dTDP-4-keto-6-deoxy-a-D-glucose 3, the product 5 or by... 

Thus far only three reports regarding the directed evolution of enantioselective EHs have appeared 95,96,143), notwithstanding the fact that these enzymes, even as wild types, constitute important catalysts in synthetic organic chemistry 7-12,144,145). Indeed, since two EHs became commercially available recently, this type of biocatalysis offers exciting prospects for the practicing organic chemist. 

Oxidoreductases, which catalyze oxidation-reduction reactions and are acting, for example, on aldehyde or keto groups. An important application is the synthesis of chiral molecules, especially chiral PFCs (22 out of 38 chiral products produced on large industrial scale are already made using biocatalysis). 

The perspectives for an increasing use of biotechnology processes (biocatalysis, microbial fermentation) for LMW fine chemicals are promising. Substitution of traditional chemicals by biotechnology processes constitutes the most important means for reduction of manufacturing cost for existing fine chemicals. By 2010,30-60% of fine-chemical production processes are expected to comprise a biotechnology step ... 

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