Problem Solving in Enzyme Biocatalysis
Lorena Wilson, Carlos Vera
Language: English
Pages: 344
ISBN: 1118341716
Format: PDF / Kindle (mobi) / ePub
Enzyme biocatalysis is a fast-growing area in process biotechnology that has expanded from the traditional fields of foods, detergents, and leather applications to more sophisticated uses in the pharmaceutical and fine-chemicals sectors and environmental management. Conventional applications of industrial enzymes are expected to grow, with major opportunities in the detergent and animal feed sectors, and new uses in biofuel production and human and animal therapy.
In order to design more efficient enzyme reactors and evaluate performance properly, sound mathematical expressions must be developed which consider enzyme kinetics, material balances, and eventual mass transfer limitations. With a focus on problem solving, each chapter provides abridged coverage of the subject, followed by a number of solved problems illustrating resolution procedures and the main concepts underlying them, plus supplementary questions and answers.
Based on more than 50 years of teaching experience, Problem Solving in Enzyme Biocatalysis is a unique reference for students of chemical and biochemical engineering, as well as biochemists and chemists dealing with bioprocesses.
Contains: Enzyme properties and applications; enzyme kinetics; enzyme reactor design and operation 146 worked problems and solutions in enzyme biocatalysis.
the reaction at 27 C and pH 8.0 was 0.25 and the affinity of the enzyme for D-xylulose was 75% higher than that for D-xylose. Evaluate the kinetic parameters and propose a rate expression for such reaction. Answer: Vmax,S ¼ 140 mmol Á minÀ1 Á mLÀ1; KM,S ¼ 15 mM. Vmax,P ¼ 320 mmol Á minÀ1 Á mLÀ1; KM,P ¼ 8.57 mM. v¼ 9:33 Á ½S À 37:34½P 0:067 Á ½S þ 0:1167 Á ½P þ 1 2.33 Lipases are used to allow the separation of racemic mixtures by the selective hydrolysis of one of the esters of the
is expressed when a certain condition is met under the influence of EDR. From Equations 3.16 and 3.17, h can be expressed in terms of measurable entities (b0 and a): qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ð1 þ b0 Þ 1 þ a þ b0 À ð1 þ a À b0 Þ2 þ 4b0 (3.18) h¼ 2b0 a A convenient way of representing Equation 3.18 is shown in Figure 3.4. At low values of a (insignificant EDR), behavior is typically Michaelian, but as a increases the dependence of h on b0 becomes progressively more linear.
linear regression of the data using Lineweaver–Burk or Eaddie–Hofstee plots (see Section 2.6), the following results are obtained: Ethyl alcohol is a competitive inhibitor of trypsin. Maximum reaction rate of BAEE hydrolysis: Vmax ¼ 50 mmol Á hÀ1 Á cmÀ2. Michaelis constant for BAEE: KM ¼ 12 mM. Competitive inhibition constant by ethanol KI ¼ 91.5 mM (inhibition is mild). Results may have significant error: the KM value obtained is outside the substrate range covered and KI is determined
sÀ1. Determine the variation in the global effectiveness factor of the catalyst (hG) with respect to the average diameter of the gel particles (dp) in the range from 0.1 to 1.0 mm. Assume first-order kinetics for lactosucrose concentration. Answer: dp (mm) hG 0.1 0.96 0.2 0.85 0.3 0.73 0.4 0.63 0.5 0.54 0.6 0.48 0.7 0.42 0.8 0.38 0.9 0.34 1.0 0.31 3.33 Penicillin G acylase (penicillin amidohydrolase, EC 3.5.1.11) is a key enzyme in the production of semisynthetic b-lactam antibiotics,
accuracy of results. If the same enzyme is now immobilized on spherical particles of polyacrylamide gel, determine the maximum allowable catalyst particle size that will obtain a global effectiveness factor not less than 0.8. Assume in this case that the reaction of synthesis is first-order with respect to 7ACCA concentration. The effective diffusion coefficient of 7ACCA inside the polyacrylamide gel is 2.5 Á 10À3 cm2 Á minÀ1 and the density of the gel is 1.1 g Á cmÀ3. Make any assumptions