Development of bioreactors for application of biocatalysts in biotransformations
and bioremediation*
Stephanie G. Burton**
Department of Biochemistry and Microbiology, Rhodes
University, Grahamstown, 6140, South Africa
Abstract: Biotransformation systems, whether used for environmentally
benign biocatalysis of synthetic reactions, or bioremediation of pollutants,
require suitable biocatalysts and suitable bioreactor systems with particular
characteristics. Our research focuses on the bioconversion of organic
compounds, many of which are industrial residues, such as phenols, poly-aromatic
hydrocarbons, heterocyclic compounds, and polychlorinated biphenyls.
The purpose of such biotransformations can be twofold: firstly, to remove
them from effluents and convert them to less toxic forms, and secondly,
to convert them into products with economic value. We conduct research
in utilizing various isolated-enzyme and whole-cell biological agents;
bioreactors, including novel membrane bioreactors, are used as a means
of supporting/immobilizing, and hence applying, these biocatalysts in
continuous systems. In addition, the enzyme systems are characterized
biochemically, to provide information which is required in modification,
adaptation, and scale-up of the bioreactors. The paper summarizes research
on application of biofilms of fungal and bacterial cells and their enzymes,
including hydrolases, polyphenol oxidase, peroxidase and laccase, in
bioreactor systems including continuously operating membrane bioreactors.
* Lectures presented at the International Symposium
on Green Chemistry, Delhi, India, 10-13 January 2001. Other presentations
are published in this issue, pp. 77-203.
** E-mail: [email protected];
Tel: 27-46-6038443; Fax: 27-46-6223984