Inactivation of laccase and enzymatic removal of phenol from water.

Date of Award


Degree Type


Degree Name



Civil and Environmental Engineering

First Advisor

Biswas, N.


Engineering, Civil.




Laccase, as a developmental preparation from an industrial enzyme producer, catalyzes the oxidation of phenols. The reaction products are insoluble polymers and are readily removed from the solution. Experiments were conducted to evaluate the potential use of laccase in an alternative enzyme based treatment technology to remove parent phenol from buffered distilled water at room temperature. All tests were conducted in continuously stirred batch reactor. pH was optimized. At an optimum condition of pH, effects of substrate concentration, product formation, dissolved oxygen (DO) availability, hydrogen peroxide addition, and aeration on phenol removal were investigated. The turnover capacity of laccase (defined as mM of phenol converted per LACU of laccase inactivated) was observed for different phenol concentrations. The optimum pH for the parent phenol ranged from 5.0 to 6.0. At a pH of 5.0 and an enzyme concentration of 0.067 LACU/mL more than 90% phenol removal of 1mM substrate concentration was achieved after 5h. For higher substrate concentration (up to 4mM), there was a linear increase in percent phenol removal. There was almost no difference in percent phenol removal for 4 and 5 mM phenol. Aeration and hydrogen peroxide addition increased the DO concentration but had no effect on the progress curve for phenol removal. The polymeric products formed were found to reduce the enzyme activity and therefore the turnover capacity drastically after a certain concentration is reached. Removal of precipitates reduced the loss of enzyme activity and enhanced the phenol removal. A reactor design concept was developed based on the findings related to polymer formation, which provides a basis for further investigation into reactor development based on the findings.Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .D37. Source: Masters Abstracts International, Volume: 43-01, page: 0263. Advisers: N. Biswas; J. K. Bewtra; K. E. Taylor. Thesis (M.A.Sc.)--University of Windsor (Canada), 2004.