Date of Award

1996

Publication Type

Doctoral Thesis

Degree Name

Ph.D.

Department

Civil and Environmental Engineering

Keywords

Engineering, Environmental.

Rights

info:eu-repo/semantics/openAccess

Abstract

Additives can be used in the horseradish peroxidase (HRP) catalyzed polymerization of phenolic compounds to increase the enzyme turnovers by more than 100-fold. In addition to polyethylene glycol (PEG) and gelatin, some polyelectrolytes may also prove effective as additives. The HRP saving is contingent on the nature of the additives and phenolic compounds. PEG appears to be the best choice from all perspectives. In the presence of additives, the optimum pH range becomes wider and the optimal pH is closer to neutral. Enzyme inactivation is mainly caused by the polymer products. Most of the additives are incorporated covalently with the polymer product during the reaction. HRP and additive interact with the polymer product according to their ratio of partition affinities for the polymer product. Enzyme inactivation is alleviated because of the small ratio. A computer model has been developed which includes a second order Michaelis-Menten equation with respect to the concentrations of phenol and hydrogen peroxide, and two equations based on inactivations caused by both polymer product and hydrogen peroxide. Experimental data prove that the model output can predict experimental behavior realistically under a variety of reaction conditions. The model has been verified by predicting some independent experimental results. Although the model is obtained from batch reactors, it can also be applied to plug flow reactors and continuous stirred tank reactors as well. Experiments prove that there is no need to stir the reaction mixture during the entire reaction period. Batch reactors and plug flow reactors have an identical reaction curve. Because of the addition of additives, continuous stirred tank reactors need very long times to complete the reaction at the minimum HRP dose. A plug flow reactor system is recommended for the reaction in the presence of additives. Such a system consists of a small mixing tank followed by a tank in which the reaction and the settling occur simultaneously.Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1996 .W8. Source: Dissertation Abstracts International, Volume: 59-08, Section: B, page: 4366. Thesis (Ph.D.)--University of Windsor (Canada), 1996.

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