Engineering enzyme reaction kinetics

In the first section of this book, the brief introduction about biochemical engineering is given in chapter 1. The second chapter deals with basics of enzyme reaction kinetics. The third chapter deals with an important aspect in enzyme bioprocess i.e. immobilization of enzyme and its kinetics. Chapter 4 is concerned about the industrial bioprocess involving starch and cellulose. 

Figure 5.1 Approach to kinetic modeling of enzyme reactions linkage of different elements of enzyme reaction engineering (top) parameter estimation and determination of operating points (bottom) (Bommarius, 1993).

The 1950s saw a change in emphasis from the analysis of bio-chemistry-as-kinetics to that of biochemistry-as-information. The theoretical rationale for this transition was provided by the growth of the new sciences associated with the development of computers. Theories of control , feedback , and information transfer were collated in 1948 by the American engineer and mathematician Norbert Wiener under the name of cybernetics. As more and more became known about the mechanisms of individual enzymic reactions, about their energy-requirements, and about the workings of series of enzymes in the harmony of metabolic pathways, biochemists seized on these new concepts in order to probe the ways in which the cell controlled and regulated its own metabolism how, so to speak, it decided at any one time... 

Kinetic parameters are defined in Sect. 7-4. Two examples will illustrate the implications of complex reactions in enzyme reaction engineering. 

With respect to benzaldehyde, (R)-oxynitrilase exhibits saturation kinetics (Michaelis Menten kinetics, see Sect. 7.4.2.1) and a maximum reaction rate is reached above a concentration of about 5 mmol L 1. The chemical reaction presents a linear increase of the reaction rate with increasing benzaldehyde concentration, representing first order kinetics, when the concentration of HCN is kept constant (see Fig. 7-13). As a consequence the enzymatic reaction becomes more dominating at lower concentrations of the substrate benzaldehyde (for HCN as substrate the same kinetic behavior occurs, data not shown). Accordingly an enzyme reactor would be suitable that works under minimum average substrate concentrations. These requirements are satisfied by the continuous stirred tank reactor (CSTR). In Sect. 7.5.2.1 this aspect of enzyme reaction engineering will be discussed further. 

Kurochkina VB, Nys PS (2002) Kinetic and thermodynamic approach to design of processes for enzymatic synthesis of betalactams. Biocatal Biotransform 20(1) 35-41 Lee SB, Ryu DDY (1982) Reaction kinetics and mechanism of penicillin amidase a comparative study of computer simulation. Enzyme Microb Technol 4 35-38 Lin WJ, Kuo BY, Chou CP (2001) A biochemical engineering approach for enhancing production of recombinant penicillin acylase in Escherichia coli. Bioproc Biosys Eng 24 239-247 Lindsay JP, Clark DS, Dordick JS (2004) Combinatorial formulation of biocatalyst preparation for increased activity in organic solvents salt activation of penidllin amidase. Biotechnol Bioeng 85(5) 553-560... 

Since enzyme is not shown in the reaction we assume an elementary rate equation may explain the above reactions. The simple kinetics are discussed in most fermentation technology and chemical reaction engineering textbooks.8-10... 

This chapter discusses the aspects of the kinetic behavior of reactions in liquid solutions that are most germane to the education of a chemical engineer. Particular emphasis is placed on catalysis by acids, bases, and enzymes and a useful technique for correlating kinetic data. 

BRADLEY A. SAVILLE is an Associate Professor of Chemical Engineering at i the University of Toronto. He received his B.Sc. and Ph.D. in chemical engi-neering at the University of Alberta. He is the author or co-author of over 25 research articles on enzyme kinetics, pharmacokinetics, heterogeneous reactions in biological systems, and reactors for immobilized enzymes. He is a member, of the Chemical Institute of Canada, the Canadian Society of Chemical Engineering, and Professional Engineers Ontario. 

The recent literature in bioelectrochemical technology, covering primarily the electrochemical aspects of enzyme immobilization and mediation, includes few reports describing engineering aspects of enzymatic biofuel cells or related devices. Current engineering efforts address issues of catalytic rate and stability by seeking improved kinetic and thermodynamic properties in modified enzymes or synthesized enzyme mimics. Equally important is the development of materials and electrode structures that fully maximize the reaction rates of known biocatalysts within a stable environment. Ultimately, the performance of biocatalysts can be assessed only by their implementation in practical devices. 

If a certain process can produce a product, it is important to know how fast the process can take place. Kinetics deals with rate of a reaction and how it is affected by various chemical and physical conditions. This is where the expertise of chemical engineers familiar with chemical kinetics and reactor design plays a major role. Similar techniques can be employed to deal with enzyme or cell kinetics. To design an effective bioreactor... 

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