Depolymerization of Lignin to Produce Value Added Chemicals

Dr. Pratima Bajpai is currently working as a Consultant in the field of Paper and Pulp. She has over 36 years of experience in research at the National Sugar Institute, University of Saskatchewan, the University of Western Ontario, in Canada, in addition to the Thapar Research and Industrial Development Centre, in India. She also worked as a visiting professor at the University of Waterloo, Canada and as a visiting researcher at Kyushu University, Fukuoka, Japan.

List of Figures viii

List of Tables x

Preface xii

Acknowledgements xiii

1 General Background and Introduction 1

1.1 Structural and Chemical Composition of Lignin 2

1.2 Major Backbone Units and Representative Linkages in Lignin Molecules 2

1.3 Types of Lignin 6

2 Isolation of Lignin 12

2.1 Lignosulfonates 18

2.2 Kraft Lignin 18

2.3 Soda Lignin 20

2.4 Steam Explosion Lignin 20

2.5 Organosolv Lignins 21

3 Lignin Depolymerization Technologies 29

3.1 Thermal Depolymerization 30

3.1.1 Pyrolysis 30

3.1.2 Hydrothermal Liquefaction 37

3.2 Biological Depolymerization 53

3.2.1 Lignin Depolymerization by Fungi 53

3.2.2 Lignin Depolymerization by Bacteria 56

3.2.3 Lignin Depolymerization by Enzymes 64

3.2.3.1 Laccase 65

3.2.3.2 Lignin Peroxidase 70

3.2.3.3 Manganese Peroxidase 71

3.2.3.4 Versatile Peroxidase 72

3.2.3.5 β-etherase 72

3.2.3.6 Biphenyl Bond Cleavage Enzyme 73

3.3 Chemical Depolymerization 87

3.3.1 Acid-catalyzed Depolymerization 87

3.3.2 Base-catalyzed Depolymerization 90

3.3.3 Ionic Liquid-assisted Depolymerization 95

3.3.4 Supercritical Fluids-assisted Lignin Depolymerization 98

3.3.5 Metallic Catalysis 104

3.4 Oxidative Depolymerization of Lignin 125

3.5 Microwave-aided Depolymerization 133

3.6 Electrochemical Lignin Depolymerization 145

3.7 Reductive De-polymerization of Lignin 151

4 Lignin-first Biorefining Process 156

4.1 Introduction 156

4.2 The Revolutionary "Lignin-first" Method for Lignocellulosic Catalytic Valorization 157

4.2.1 Reductive Catalytic Fractionation 157

4.2.2 From Phenolic Units to Value-added Products 163

4.3 Future Challenges 165

5 Lignin Production 173

5.1 Introduction 173

5.2 Pilot-scale 174

5.2.1 Ammonia Fiber Explosion Lignin 174

5.2.2 Steam Explosion Process 175

5.2.3 BioFlex Process 175

5.2.4 German Lignocellulose Feedstock Biorefinery Project 176

5.2.5 ProesaR Lignin 176

5.2.6 FABIOLATM Lignin 177

5.2.7 Fast Pyrolysis Lignin 178

5.2.8 Sequential Liquid-lignin Recovery and Purification Technology 178

5.3 Commercial scale 179

5.3.1 LignoForceTM Technology 179

5.3.2 LignoBoostTM Technology 180

5.3.3 SunCarbon Lignin 180

5.3.4 Production of Lignosulfonates 181

5.3.5 Kraft Lignin Production 181

5.3.6 Organosolv and Soda Lignin 182

5.3.7 Thermo-mechanical Pulp-bio Lignin 183

5.4 Future Perspectives 183

6 Applications of Lignin 188

6.1 Introduction 188

6.2 Applications 189

6.2.1 Aromatics, Phenolics and Flavoring Compounds 189

6.2.2 Carbon Materials 191

6.2.3 Lignin-based Nanomaterials 192

6.2.4 Biomedical Application 192

6.2.5 Lignin-based Nanocomposites 193

6.2.6 Urethanes and Epoxy Resins 194

6.2.7 Controlled Release Fertilizer 194

6.2.8 Biosensor and Bioimaging 195

6.2.9 Hydrogen Production 197

6.2.10 Battery Material for Energy Storage 198

6.2.11 Dust Control Agent 200

6.2.12 Bitumen Modifier in Road Industry 200

6.2.13 Cement Additives and Building Material 201

6.2.14 Bioplastics 202

6.2.15 Use of Lignin as a Binder 203

6.2.16 Lignin as Dispersant 203

6.2.17 Lignin as Food Additives 203

6.2.18 Lignin as Sequestering Agent 203

6.2.19 Lignin Bio-oil 204

7 Lignin -- Business and Market Scenario 212

7.1 Introduction 212

7.2 Lignin Market 213

8 Challenges and Perspectives on Lignin Valorization 219

8.1 Introduction 219

8.2 Challenges and Perspectives on Lignin Utilization 220

Index 225