Bioorganic Synthesis Engineering

Several books and reviews have appeared on the industrial applications of biocatalysts, for example, Trevan (1980), Chibata et al. (1982), Dixon and Webb (1984), Tramper (1985), Wiseman (1985), Chibata (1978, 1987), Scott (1987), Peppier and Reed (1987), Cheetham (1987), Nakamura et al. (1988), Dordick (1991, 1992), Tanaka et al. (1993), Govardhan and Margolin (1995), Adams et al. (1995), and also on the design and analysis of biocatalytic reactors, for example, Bailey and Ollis (1986), Van t Riet and Tramper (1991), Shuler and Kargi (1992), Peter (1992), Dunn et al. (1992), Tanaka et al. (1983), Vieth and Wolf (1994), Nielsen and Villadsen (1994). 

The objectives of this chapter are to outline the basic aspects of cell and enzyme action, review the methods of immobilization, outline the principles of bioreaction analysis, briefly describe the methods of bioreactor design, and conclude by giving several examples of the use of cells and enzymes in organic technology and synthesis, including enantioselective synthesis. 

There are two classes of microbes, procaryotes and eucaryotes. Procaryotic cells are usually characterized by simple unicellular structures. Exceptions are also known such as the cyanobacteria, which are often multicellular. The only procaryotes are bacteria which are also the most abundant form of life on earth. Eucaryotes encompass all other forms of life, including animal and plant. 

Eucaryotic organisms can be either unicellular (e.g. protozoa) or more complex structures. They all contain organelles such as mitochondria, ribosomes (also found in procaryotes), lysosomes, and plastids. Yeasts are unicellular fungi 

All enzymes are proteins. They are isolated from microbial fermentations and animal and plant by-products. The one feature of enzymes that places them above all other forms of catalysts is their remarkable specificity to a desired product. Enzymes are essentially large molecules whose molecular weights range from 10,000 to several million and whose cross-sectional dimensions extend up to about 10 nm. To develop catalytic action, however, many enzymes require the cooperation of low molecular weight nonprotein substances known as coenzymes or cofactors. The protein moiety in such cases is specifically referred to as apoenzyme. There are essentially six classes of common enzymes, as listed in the first part of Table 20.1. 

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Bioorganic Synthesis Engineering 655 Table 20.4 Linearized forms of the Michaelis-Menten equation... 

Sears, R. and Wong, C. H., Engineering enzymes for bioorganic synthesis peptide bond formation, Biotechnol Prog., 12, 423 33, 1996. 

This book is particularly useful to those without a strong background in chemical engineering and gives a very clear exposition (with easily understandable mathematics) of biokinetics, dynamic differential balances, and modeling of a number of reactions and reactor types normally encountered in bioorganic synthesis. 

Huang, Q., Roessner, C.A., Croteau, R. and Scott, A.I. (2001) Engineering Escherichia coli for the synthesis of taxadiene, a key intermediate in the biosynthesis of Taxol. Bioorganic Medicinal Chemistry, 9, 2237-2242. 

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