Biocatalysis opportunities

Roberts, N. J., Lye, G. J. Application of room temperature ionic liquids in biocatalysis Opportunities and challenges. In Ionic Liquids Industrial Applications for Green Chemistry, Rogers, R. D., Sheldon, K. R. Eds., American Chemical Society Washington, D.C., 2002, Vol. ACS Symposium Series 818. 

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

Special attention is given to the integration of biocatalysis with chemocatalysis, i.e., the combined use of enzymatic with homogeneous and/or heterogeneous catalysis in cascade conversions. The complementary strength of these forms of catalysis offers novel opportunities for multi-step conversions in concert for the production of speciality chemicals and food ingredients. In particular, multi-catalytic process options for the conversion of renewable feedstock into chemicals will be discussed on the basis of several carbohydrate cascade processes that are beneficial for the environment. 

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. 

Another environmental issue is the use of organic solvents. The use of chlorinated hydrocarbons, for example, has been severely curtailed. In fact, so many of the solvents favored by organic chemists are now on the black list that the whole question of solvents requires rethinking. The best solvent is no solvent, and if a solvent (diluent) is needed, then water has a lot to recommend it. This provides a golden opportunity for biocatalysis, since the replacement of classic chemical methods in organic solvents by enzymatic procedures in water at ambient temperature and pressure can provide substantial environmental and economic benefits. Similarly, there is a marked trend toward the application of organometal-lic catalysis in aqueous biphasic systems and other nonconventional media, such as fluorous biphasic, supercritical carbon dioxide and ionic liquids. ... 

In 1989, Sidney Altman and Thomas Cech were awarded the Nobel Prize in chemistry for a discovery that changed not only the field of biocatalysis, but also our perception of the molecular basis of life on Earth [118]. They showed that RNA, which until then was considered an innocent carrier of hereditary information, can actually catalyze reactions [119,120]. Two different RNA molecules were shown to catalyze site-specificphosphodiesterbondcleavage,withrate enhancements ofseveral orders of magnitude. This discovery of nonprotein biocatalysts came as a complete surprise, and laid open many questions and opportunities [121,122]. 

The success of biocatalysis depends ultimately on the economics of specific processes. It provides enormous opportunities, and with the introduction of each new process, experience and confidence accumulate. It thus becomes easier to... 

The production of single enantiomers of drug intermediates is increasingly important in the pharmaceutical industry. Biocatalysis provides organic chemists an alternate opportunity to prepare pharmaceutically important chiral compounds. The advantages of biocatalysis over chemical catalysis are that enzyme-catalyzed reactions are stereoselective and regioselective, and can be carried out at ambient temperature and atmospheric pressure providing an environmentally friendly system. The selective examples presented in this... 

The exciting technical opportunities in biocatalysis are tempered by the major barriers to commercialization which still exist. Most notably, these include low stability of an expensive catalyst, and the high separation and capital costs associated with low concentrations of reactants and products. 

General reviews of polymer biocatalysis can be found in (a) Cheng, H.N., and Gross, R.A. (eds) (2008) Polymer Biocatalysis and Biomaterials II, ACS Symposium Series 999, American Chemical Society. (b) Cheng, H.N., and Gross, R.A. (eds) (2005) Polymer Biocatalysis and Biomaterials, ACS Symposium Series 900, American Chemical Society. (c) Kobayashi, S., and Makino, A. (2009) Enzymatic polymer synthesis an opportunity for green polymer chemistry. Chem. Rev., 109, 5288-5353. (d) Kobayashi, S Uyama, H., and Kimura, S. (2001) Enzymatic polymerization. Chem. Rev.,... 

R. J. Kazlauskas, Molecular modeling and biocatalysis explanations, predictions, limitations, and opportunities. Curr. Opin. Chem. Biol. 2000,4(1), 81-88. 

The power of directed evolution is now well documented. These methods are robust and are able to improve industrial enzymes in reasonably short times. The first laboratory-evolved enzymes are now used commercially in laundry detergents12011 other commercial applications are on the horizon. Directed evolution may well help move biocatalysis from an enabling tool to a lowest cost approach . It also offers new opportunities to engineer multi-enzyme pathways and even whole microbes [69- 224> 2251, which will lead to straightforward single-pot, multi-enzyme bioconversions and new fermentation processes based on green resources such as glucose or inexpensive waste materials. 

Biocatalysis and biomaterials are dynamic areas of research that have continued to attract a lot of attention. Developments in these areas are largely fueled by demands for sustainable technologies, a desire to decrease our dependence on petroleum, and commercial opportunities to develop green products. Publications and patents in these fields continue to grow as more people are involved in research and commercial activities. 

As stated in Section 5.2.2.5.1, biocatalysis is stiU a very small niche area within the field of industrial organic synthesis in general. Even though the combination of ILs and biocatalysts may offer several exciting opportunities, we do not believe that this will change the overall position of biocatalysis significantly. Rather, the combination of ILs and biocatalysis will only become yet another niche area within the field of biocatalysis. 

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