Contents
Preface ix
List of contributors xi
1 Enzymes 1
r. o. jenkins, de montfort university, uk
1.1 Introduction 1
1.2 Classification and nomenclature of enzymes 3
1.3 Protein structure 6
1.4 Forces that stabilise protein molecules 18
1.5 Properties of proteins 19
1.6 Biosynthesis of proteins 24
1.7 Post-translational modification of proteins 29
1.8 Enzymatic catalysis 30
1.9 Future trends 36
1.10 Further reading 39
1.11 Bibliography 40
2 Substrates and their structure 42
g. buschle-diller, auburn university, usa
2.1 Non-fibrous substrates and non-substrates 42
2.2 Textile fibers as substrates for enzymes 64
2.3 References 82
3 Catalysis and processing 86
a. cavaco-paulo, university of minho, portugal
and g. gübitz, graz university of technology, austria
3.1 Basic thermodynamics and enzyme kinetics 87
3.2 Function of textile processing enzymes 89
3.3 Homogeneous and heterogeneous enzyme catalysis and kinetics 99
3.4 Major enzymatic applications in textile wet processing 107
3.5 Promising areas of enzyme applications in textile processing 113
3.6 References 116
4 Process engineering and industrial enzyme applications 120
v. a. nierstrasz and m. m. c. g. warmoeskerken,
university of twente, the netherlands
4.1 Introduction 120
4.2 Large-scale industrial enzyme applications in textiles: an overview 121
4.3 Industrial applications of enzymes in wet textile processing 123
4.4 Mass transfer in textile materials 131
4.5 Process intensification: enhancement of mass transfer in textile materials 142
4.6 Mass transfer and diffusion limitation in immobilised enzyme systems 148
4.7 References and further reading 154
5 Practical aspects of handling enzymes 158
h. b. m. lenting, tno institute for industrial
technology, the netherlands
5.1 Introduction 158
5.2 Enzyme activity 159
5.3 Stabilisation of enzymatic activity 169
5.4 Handling of enzymes 181
5.5 Health and safety issues 192
5.6 References 197
6 Effluent treatment – Enzymes in activated sludge 199
j. binkley, university of manchester institute of science and technology and a. kandelbauer, graz university of technology, austria
6.1 Hazardous waste 200
6.2 Types of textile effluent 201
6.3 Methods of water treatment for incoming water 203
6.4 Treatment of wastewaters from the textile industry 203
6.5 Effluent treatment 205
6.6 The use of activated sludge for the removal of colour 208
6.7 Decolourisation by enzymes, fungi, and by biosorption and
enrichment cultures 212
6.8 References 219
Index 223
Preface
The first use of enzymes in textile processing was reported in 1857 when starch-sized cloth was soaked with liquor containing barley. Later, in 1900, this process was slightly improved using malt extract, but only in 1912 with the use of animal and bacterial amylases was the process of enzymatic desizing introduced into many textile factories. Interestingly, amylases remained the only enzymes applied in textile wet processing for almost 70 years. In the late 1980s, cellulases were introduced with great success for depilling and defuzzing cellulose-based fabrics as well as to age garments made from materials like denim to obtain the stone-washed look. Since the early 1990s, catalases have been introduced to destroy hydrogen peroxide after bleaching, reducing the consumption of water. Pectin degrading enzyme products have been commercialised for cotton processing to replace traditional alkaline scouring. Intense investigations are being conducted on new enzyme applications for almost all cotton processing steps and for modification of cellulosic, proteic and synthetic fibres. Textile processing with enzymes is therefore a new emerging and multidisciplinary area. Engineers with knowledge and basic understanding in both textile technology and enzymology will help to introduce these environmentally-friendly processes more extensively to the industry. However, only little information about enzymes for textile processing can be found in educational programmes or in the literature.
This book was put together to generate a basic understanding of enzymes, textile materials and process engineering. It can serve as a textbook for everyone interested in the subject; students, scientists and engineers alike with a basic background in either textiles, biotechnology, chemistry or engineering. The book covers all relevant aspects of textile processing with enzymes, from the chemical constitution and properties of textile materials as potential substrates for enzymes, to processing of these materials, and from basic biochemistry and enzymology to industrial application of these biocatalysts.
Chapter 1 deals with the fundamental aspects of enzymes determining catalytic properties. It is intended to provide a basis for the understanding of many aspects related to the application of enzymes considered in subsequent chapters. Chapter 2 gives an overview of non-fibrous and fibrous materials as substrates for enzymes. Included is a discussion on dyes, sizes, textile fibres and textile auxiliaries that might influence enzymatic reactions. Chapter 3, about catalysis and processing, gives an overview about the function and application of enzymes used in textile processing. Basic thermodynamics and enzyme kinetics, function of textile-processing enzymes, homogenous and heterogeneous catalysis and important applications of enzymes in textile wet processing are addressed. Chapter 4 gives insights into process engineering and describes major problems in the industrial applications of enzymes in textiles. Important facts about the influence of mass transfer are described. Chapter 5 discusses practical aspects of handling enzymes, like enzyme activity. Operational and storage stabilities are discussed in detail as well as health and safety issues. The last chapter, Chapter 6, deals with effluent treatment and the potential use of enzymes therein.