[Frontiers in Bioscience E4, 1127-1149, January 1, 2012] 1127 Versatility of oxidoreductases in the remediation of environmental pollutants Tukayi Kudanga 1 , Stephanie Burton 1 , Gibson S. Nyanhongo 2 , Georg M. Guebitz 2 1 Biocatalysis and Technical Biology Research group, Cape Peninsula University of Technology, Bellville Campus, Symphony Way, PO Box 1906, Bellville, 7535, Cape Town, South Africa, 2 Graz University of Technology, Institute of Environmental Biotechnology, Petersgasse 12/1, A-8010, Graz, Austria TABLE OF CONTENTS 1. Abstract 2. Introduction 3. Brief review of oxidative enzymes and reaction mechanisms 3.1. Laccase (benzenediol:oxygen oxidoreductase, EC 1.10.3.2) 3.2. Tyrosinase (Tyros; E.C. 1.14.18.1, monophenol monoxygenase) 3.3. Lignin peroxidase (LiP; EC: 1.11.1.14) 3.4. Manganese peroxidase (MnP; EC 1.11.1.13 3.5. Coprinopsis cinerea peroxidase (CiP; EC 1.11.1.7) 3.6. Versatile peroxidase (VP; EC 1.11.1.16) 3.7. Heme-thiolate peroxidases 3.8. Dye-decolorizing peroxidases (/DyP; EC 1.11.1.X) 3.9. Secreted plant peroxidases (horseradish peroxidase (HRP, EC 1.11.1.7) and soybean peroxidase (SBP, EC 1.11.1.7) 4. Applications of oxidoreductases for environmental purposes 4.1. Soil remediation 4.2. Waste water treatment 4.3. Decoloration of dyes 4.3.1. Peroxidases in dye decoloration/degradation 4.3.2. Laccases in dye decoloration/degradation 5. Perspective 6. Acknowledgements 7. References 1. ABSTRACT Enzymatic transformation of recalcitrant and other pollutants is a promising eco-friendly alternative to physico-chemical methods in environmental remediation. This review summarizes some of the significant advances in applications of oxidative enzymes for treatment of xenobiotics. The review also discusses some of the underlying principles and enzyme reaction mechanisms in the detoxification or removal of xenobiotic compounds such as dyes, phenolic compounds, nitroaromatic compounds and polyaromatic hydrocarbons, as a way of remediating contaminated soils or wastewaters. 2. INTRODUCTION Life on this planet depends entirely on the continuous recycling of elements among living organisms and their interaction with non-living things. Unfortunately, over the years, the massive mobilization of resources and the industrial synthesis of various chemicals have resulted in waste treatment problems leading to environmental pollution and limited incorporation of most of the synthesized molecules in the biological cycles. This is particularly true for many xenobiotic compounds which exhibit structural elements or substituents that are rarely found in nature. Thus environmental pollution is now a