Alginates: Biology and Applications (eBook)

Bernd H. A. Rehm (Herausgeber)

eBook Download: PDF

2009 | 2009
VIII, 266 Seiten
Springer Berlin (Verlag)
978-3-540-92679-5 (ISBN)

Infos

'Alginates: Biology and Applications' provides an overview of the state of art of alginate material properties, genetics and the molecular mechanisms underlying alginate biosynthesis as well as applications of tailor-made alginates in medicine, food and biotechnology.

Topics treated are: material properties of alginates, alginate production: precursor biosynthesis, polymerization and secretion, bacterial system for alginate uptake and degradation, enzymatic alginate modification, alginate gene regulation, role of alginate in bacterial biofilms, microbial production of alginates: physiology and process aspects, alginate-based blends and nano/microbeads, applications of alginates in food, alginate and its comonomer mannuronic acid: medical relevance as drugs.

Inhalt

Preface 6
References 7
Contents 8
Material Properties of Alginates 10
1 Sources and Applications 11
2 Chemical Structure and Sequence 12
2.1 Chemical Composition 13
2.2 Comonomer Sequence 14
2.3 Natural Substituents 19
2.4 Alginate as a Polyelectrolyte 21
2.5 Conformational Properties of the Alginate Chain 24
3 Molecular Weight and Stability 26
3.1 Molecular Weight and Molecular Weight Distribution of Native Alginates 26
3.2 Chain Degradation 27
3.3 Chemical Modifications of Alginate 29
4 Alginate Solutions 30
4.1 Thermodynamic Properties 30
4.2 Nonequilibrium Properties 32
5 Ion-Binding Properties 35
6 Alginate Gels 39
6.1 Gel Formation Properties 39
6.2 Hydrogel Stability 44
6.3 Mechanical Properties 46
6.4 Diffusion Properties 54
References 55
Alginate Production: Precursor Biosynthesis, Polymerization and Secretion 63
1 Introduction 64
2 Alginate Precursor Biosynthesis 65
2.1 Alginate Biosynthesis Genes 66
2.2 GDP-Mannuronic Acid Biosynthesis 67
3 Alginate Polymerization and Secretion 69
3.1 Alginate Polymerization 69
3.2 Alginate Export 73
4 Conclusion and Future Perspectives 75
References 75
Bacterial System for Alginate Uptake and Degradation 80
1 Introduction 81
2 Alginate-Assimilating Bacterium 82
2.1 Pit Formation on the Cell Surface 82
2.2 Genome Sequence 84
3 Alginate Uptake 84
3.1 Cell Surface Receptors 86
3.2 Outer-Membrane Transporters 87
3.3 Periplasmic Binding Proteins 88
3.4 Inner-Membrane ABC Importer 90
4 Alginate Degradation 91
4.1 Endotype Alginate Lyases 91
4.2 Exotype Alginate Lyases 93
5 Concluding Remarks and Future Perspectives 94
5.1 Superchannel as Alginate Uptake System 94
5.2 Molecular Transplantation of Superchannel 95
5.3 Application of the Alginate Degradation System 97
References 98
Enzymatic Alginate Modification 102
1 Introduction 103
2 Mannuronan C-5-Epimerases 105
2.1 Early Studies on the Secreted Mannuronan C-5-Epimerase from A. vinelandii 105
2.2 Cloning and Characterization of the Mannuronan C-5-Epimerases from A. vinelandii 107
2.3 Cloning and Characterization of the Bacterial Periplasmic Mannuronan C- 5- Epimerases 109
2.4 Mannuronan C-5-Epimerases from Algae 110
2.5 Structure of the Mannuronan C-5-Epimerases 110
2.6 Mode of Action of the Secreted Mannuronan C- 5- Epimerases 111
2.7 Enzyme Specificity Epimerization of Nonnatural Uronans and Poly( guluronic acid)
2.8 In Vitro Epimerization with AlgE Epimerases 114
3 Alginate Lyases 115
3.1 Alginate Lyases as Tools To Determine Alginate Structure 115
3.2 An Alginate Lyase Is Needed To Remove Aberrantly Localized Alginate 115
4 Alginate Acetylation 116
5 Use of Alginate-Modifying Enzymes for Biotechnological Purposes 116
References 117
Alginate Gene Regulation 123
1 Introduction 124
2 Hierarchical Regulation of the Alginate Operon 124
3 AlgR, a Two-Component Regulator 125
4 AlgB, an NtrC-Family Two-Component Regulator 127
5 AmrZ, an Arc-Like DNA-Binding Protein 128
6 Ancillary Regulators of the algD Operon 129
7 Alternative Sigma Factor, s 22 129
8 Role of s 22 -MucAB and Regulated Proteolysisin a Cell Wall Stress Response 131
9 Conclusions 134
References 134
Role of Alginate in Bacterial Biofilms 140
1 Introduction 141
2 Bacterial Exopolysaccharides 141
3 Alginate Structure and Properties 142
4 Regulation of Alginate Biosynthesis 143
5 Role of Alginate in Biofilm Formation 145
6 Alginate Creates a Hydrated Biofilm Microenvironment 146
7 Alginate Production in the CF Lung 148
8 Alginate Protects Cells from Antimicrobial Agents 149
9 Alginate in Phytopathogenic Interactions 150
10 Concluding Remarks and Future Perspectives 152
References 152
Microbial Production of Alginates: Physiology and Process Aspects 157
1 Introduction 158
2 Commercial Production of Alginate 158
3 Biological Role of Alginate Production in Bacteria 160
3.1 Azotobacter vinelandii 160
3.2 Pseudomonads 163
4 Optimal Conditions for Microbial Alginate Production 166
4.1 Fermentation Conditions for Optimal AlginateProduction in A. vinelandii 166
4.2 Alginate Production by P. aeruginosa 168
4.3 Kinetics of Alginate Production 169
4.4 Non-Newtonian Alginate Fluids and the Role of Fermentor Hydrodynamics 170
5 Conclusion 172
References 172
Alginate-Based Blends and Nano/Microbeads 178
1 Introduction 179
2 Alginate Blends 180
2.1 General Methods for the Preparation of Alginate Blends 180
2.2 Applications of Alginate Blends 181
3 Alginate Microbeads and Nanobeads 186
3.1 Methods for Preparation of the Beads 186
3.2 Application of Alginate Beads 191
4 Conclusion 206
References 206
Applications of Alginates in Food 214
1 Introduction 215
2 Gelling Agents 216
3 Thickening, Stabilising and Emulsifying Agents 217
4 Encapsulation and Immobilisation 218
5 Food Coating 220
6 Physiological Effects of Dietary Alginates 221
6.1 Alginate Safety 221
6.2 Effect on Colonic Microflora 221
6.3 Reduction of Toxicity of Colonic Luminal Contents 222
6.4 Effect of Alginate on Satiety 223
6.5 Effect on Intestinal Absorption Rates 223
6.6 Effect on Plasma Cholesterol 224
6.7 Effect on Glycaemic and Insulinaemic Responses 225
7 Summary 225
References 226
Alginate and Its Comonomer Mannuronic Acid: Medical Relevance as Drugs 232
1 Introduction 233
2 Therapeutic Effects of Alginate on Experimental Acute Ulcerative Colitis 234
3 Treatment of Experimental Chronic Ulcerative Colitis with Sodium Alginate 239
4 Treatment of Experimental Immune Complex Glomerulonephritis by Sodium Alginate 240
5 Therapeutic Effects of M2000 on an Experimental Model of Rheumatoid Arthritis 245
6 Immunosuppressive Effect of M2000 in Experimental Multiple Sclerosis 247
7 Treatment of Experimental Nephrotic Syndrome with M2000 251
8 Therapeutic Effects of M2000 in Experimental Immune Complex Glomerulonephritis 255
9 Tolerability and Pharmacotoxicology of M2000 258
10 Outlook 261
References 261
Index 264

Produkt-Details

• Erscheint lt. Verlag: 28.5.2009
• Reihe/Serie: Microbiology Monographs
• Reihe/Serie: Microbiology Monographs
• Zusatzinfo: VIII, 266 p. 94 illus., 6 illus. in color.
• Verlagsort: Berlin
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Biologie ► Mikrobiologie / Immunologie
• Themenwelt: Technik
• Schlagworte: Bacterial product engineering • Biofilm • Biofilms • biomaterials • biosynthesis • Biotechnology • Desiccation-resistance • Exopolysaccharides • genes • Genetics • Intercellular matrix • microbe • Molecular mechanisms • Physiology • Seaweeds
• ISBN-10: 3-540-92679-8 / 3540926798
• ISBN-13: 978-3-540-92679-5 / 9783540926795