ENZYMES IN WASTE MANAGEMENT

Written by: Ozochima Victor Chima (B.Sc)

TABLE OF CONTENTS

Title Page

Dedication

Acknowledgement

Table of Contents

List of Figures

Abstract

CHAPTER ONE: INTRODUCTION AND DEFINITION OF TERMS

1.0 Introduction

1.1 Enzymes

1.2 Waste

1.3 Waste Management

CHAPTER TWO: SOURCES, KINDS AND CHARACTERISTICS OF ENZYMES USED IN WASTE MANAGEMENT

2.1 Sources of Enzymes used in Waste Management

2.2 Kinds of Enzymes used in Waste Management

2.2.1 Bacterial enzymes

2.2.2 Fungal enzymes

2.3 Characteristics of the Enzymes used in Waste Management

2.3.1 Polyphenol oxidases

2.3.2 Peroxidases

2.3.3 Oxygenases

2.3.4 Lipase

2.3.5 Proteases

CHAPTER THREE: APPLICATIONS OF ENZYMES IN WASTE MANAGEMENT

3.1 Reduction of Wastewater Sludge.

3.2 Composting of Organic Wastes.

3.3 Reduction of Wastes from Food Industries.

3.4 Reduction of Wastes from Animal Feed Industries.

3.5 Reduction of Wastes from Pulp and Paper Industries.

3.6 Degradation of Waste Proteins and Fats in Leather Industries.

3.7 Reduction of Wastes from Detergent Industries.

3.8 Detoxification of Pesticide Wastes.

3.9 Recycling of Sawdust.

CHAPTER FOUR: FACTORS AFFECTING THE APPLICATION OF ENZYMES IN WASTES MANAGEMENT

4.1 Ecological Factors.

4.2 Biochemical Factors.

4.3 Regulatory Constraints.

4.4 Financial Constraints.

CHAPTER FIVE: PROBLEMS OF ENZYMATIC WASTE MANAGEMENT AND THEIR SOLUTION.

5.1 Problems of Enzymatic Waste Management

5.1.1 Inadequate risk assessment of reaction by-product.

5.1.2 Problem of disposal of reaction by-products.

5.2 Solutions to Enzymatic Waste Management Problems.

5.2.1 Environmental risk assessment of reaction by–products.

5.2.2 Combined waste management approach.

CONCLUSION

REFERENCES

ABSTRACT

Enzymes are biological catalysts produced by living organisms that facilitate the conversion of substrates into products by providing favourable conditions that lower the activation energy of a reaction. Enzymes play significant and specific roles in waste management. Waste includes all items that people or companies no longer have any use for, which they either intend to get rid of or have already discarded. Waste management refers to all the activities and actions required to deal with waste from its inception to its final disposal together with waste monitoring and regulation. Waste management is highly represented by the widely accepted principle of the 3Rs–Reduce, Reuse and Recycle. The enzymes used for waste management are mostly of fungal and bacterial origin. This is because bacteria and fungi are easy to handle and can be genetically modified to produce large quantity of enzymes. Bacterial enzymes used in waste management include: oxygenases, lipases and proteases. Oxygenases are produced from Pseudomonas florescens, while lipases and proteases are isolated from Candida rugosa and Bacillus sp respectively. The fungal enzymes used in waste management include peroxidases, cellulases and phenol oxidases. Peroxidases are isolated from the white–rot fungus, Phanerochaete chrysosporium; cellulases are isolated from Aspergillus niger; while phenol oxidases are isolated from Rhizoctonia practicola, Fomus annosus and Trametes versicolor. The enzymes used in waste management have specific characteristics. Polyphenol oxidases are oxidoreductases that catalyse oxidation reaction of phenolic compounds. They require the presence of biomolecular oxygen for their activity. Peroxidases are another oxidoreductase group that catalyse a variety of reactions such as oxidation of organic compounds. Peroxidases require the presence of peroxides such as hydrogen peroxide to activate them. Cellulases are hydrolytic enzymes which degrade cellulose to reducing sugars. They do not require the presence of a cofactor for their activity. Oxygenases belong to the oxidoreductase group of enzymes. They catalyse the metabolism of organic compounds by increasing their solubility or bringing about cleavage of the aromatic ring. Lipases are ubiquitous enzymes which catalyze the hydrolysis of triacylglycerols to glycerol and free fatty acids. Proteases are hydrolytic enzymes which catalyse the breakdown of proteinaceous substances. Various applications of enzymes in waste management include: reduction of wastewaster sludge;  composting of organic wastes; reduction of wastes from food industries; reduction of wastes from animal feed industries; reduction of wastes from pulp and paper industries;  degradation of waste proteins and fat in leather industries;  reduction of wastes from detergent industries; detoxification of pesticide wastes and recycling of sawdust. Factors affecting the application of enzymes in waste management are: ecological factors, biochemical factors, regulatory constraints, and financial constraints. Problems of enzymatic waste management include: inadequate risk assessment of reaction by–product and problem of disposal of reaction by–products. Environmental risk assessment of reaction by-products and the adoption of combined waste management approach could provide a lasting solution to the problems of enzymatic waste management. Developing nations such as African countries should adopt the use of enzymes in waste management.

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