This book provides an up-to-date overview of the biological functions of melanins, their biotechnological production, and their industrial applications.
The melanins form a group of polymeric pigments found in most organisms. These natural products are generated by the oxidation of phenolic and indolic molecules yielding melanins, which include eumelanin, pheomelanin, pyomelanin, and the allomelanins. These pigments have diverse biological functions, including photoprotection, thermoregulation, antioxidation, virulence, and metal ion sequestration. Melanins have physicochemical properties that have proven useful in the optical, electronic, material, agriculture, cosmetic, pharmaceutical, and medical industries.
The chapters in this book provide an in-depth analysis of the current issues and challenges in this field. Topics covered include the properties, biogenesis, and evolution of melanosomes.
The book also addresses the synthesis and industrial production of melanins by microorganisms. The metabolic pathways for the synthesis of several types of polymeric pigments in microorganisms and their role in pathogenesis are reviewed. The large-scale production and purification of melanins to provide this product for industrial applications is a formidable challenge. Two chapters present and discuss the state-of-the-art used for the generation of microbial melanin-production strains and the processes for the biotechnological synthesis and purification of these pigments. Melanins are polymers that can interact with metals, a chapter reviews this capacity in the context of technological applications, including electrochemical energy storage and metal recovery. These polymers are materials having favorable characteristics for photonic applications, including UV blocking and broadband absorption. The current advances in the application of these pigments in optically active materials are presented and discussed.
Author(s): Guillermo Gosset
Publisher: Springer
Year: 2023
Language: English
Pages: 149
City: Cham
Preface
Contents
Melanin Synthesis in Bacteria: Who, How and Why
1 Introduction
2 Melanin Biosynthesis Pathways in Bacteria
2.1 Eumelanin (DOPA Melanin)
2.2 Pyomelanin (Homogentisate Melanin)
2.3 Polyketide Derived Melanin (PK Melanin)
2.4 Allomelanins
3 Phylogenetic Distribution of Melanin Synthesis in Bacteria
3.1 Actinobacteria
3.2 Firmicutes
3.3 Proteobacteria
3.4 Other Bacterial Phyla and Archaea
4 Control of Melanin Synthesis in Bacteria
5 Physiological Role of Bacterial Melanins
5.1 Contribution of Melanin to Bacterial Fitness in Different Environments
5.2 Melanin in Pathogenic Interactions with Animals and Plants
5.3 Melanin in Non-pathogenic Interactions
6 Concluding Remarks
References
The Role of Melanin in Fungal Disease
1 Fungal Melanin Biosynthesis
2 Melanin Structure and Localization
2.1 Cell-Wall Associated Melanin
2.2 Secreted Melanin
3 Role of Fungal Melanin in Human Disease
3.1 Cell-Host Interaction
3.2 Mechanisms of Resistance to Human Host Immune Factors
3.2.1 Oxidative Stress
3.2.2 Melanin Interference with Antifungal Drug Activity
3.2.3 Immune Evasion
4 Interactions Between Fungal Melanins and Insect Hosts
5 Role of Fungal Melanin in Plant Infections
6 Fungal Melanin as a Target for Antimicrobial Therapies
7 Concluding Remarks
References
Melanosome Origins, Diversity and Functional Relevance Across Animals
1 Melanosome Origins and Development
1.1 Non-integumentary Melanosomes
1.2 Melanosome Biogenesis
2 Melanosome Diversity Across Animal Taxa
2.1 Evolution of Melanosome Shape
3 Functional Relevance of Melanosome Diversity
3.1 General Properties of Melanin and Melanosomes
3.2 Optical Properties and Color Production by Melanosomes
3.3 Thermal Properties of Melanized Tissue
4 Novel Techniques in the Study of Melanosomes
References
Biotechnological Production of Melanins with Recombinant Microorganisms
1 Introduction
2 Enzymes Involved in Melanin Formation: Classification and Evolution
3 Production of Melanins with Genetically Engineered Microorganisms
3.1 Eumelanin Production
3.2 Pyomelanin Production
4 Production of Allomelanin and Novel Types of Melanin
5 Metabolic Engineering Applied for De Novo Synthesis of Melanins
6 Conclusions and Perspectives
References
Extraction, Purification, and Characterization of Microbial Melanin Pigments
1 Introduction
2 Extraction of Melanin
3 Purification of Melanin
4 Preliminary Confirmation of Melanin
5 Characterization of Melanin
5.1 UV-Visible Spectroscopy
5.2 Electron Paramagnetic Resonance (EPR)
5.3 Electrical Properties of Melanin
5.4 Fourier-Transform Infrared Spectroscopy (FT-IR)
5.5 X-Ray Photoelectron Spectroscopy (XPS)
5.6 Raman Spectroscopic Analysis
5.7 Nuclear Magnetic Resonance (NMR) Spectroscopy
6 Conclusion
References
Exploiting Melanin-Metal Interactions for Emerging Technologies
1 Introduction
2 Chemical Structure and Physicochemical Properties of Eumelanin
2.1 Eumelanin
2.2 Eumelanin vs Other Melanins
2.3 Chemical and Physical Disorder
2.4 Functional Properties of Eumelanin
3 Electrochemical Properties of Eumelanin: Focus on Metal Ions
3.1 Aspects of Redox Properties in Eumelanin, in Presence of Alkaline and Ammonium Ions
3.2 Redox Properties (Multivalent Ions)
4 The Effect of Metal Ions on the Electronic Transport of Eumelanin
4.1 Monovalent Cations
4.2 Multivalent Cations
5 On the Interactions Between Eumelanin and Metal Electrodes
6 On the Possibility to Use Eumelanin in Metal Extraction from E-Waste
6.1 Hydrometallurgy
6.2 Biohydrometallurgy
6.3 Pyrometallurgy
6.4 A Possible Perspective on the Interaction of Melanin with Metals for e-Waste Recovery
References
Fundamentals and Applications of Optically Active Melanin-Based Materials
1 Introduction
2 Chemical Structure
2.1 Classifications of Melanin
2.2 Complex Hierarchical Structure of Melanin
3 Absorption-Related Properties and Applications
3.1 Optical Absorption
3.2 Black Additives
3.3 Protection from Electromagnetic Radiation
3.4 Photothermal Effect
3.5 Fluorescence
4 Scattering-Related Properties and Applications
4.1 Single Particle Scattering
4.2 Scattering from Assemblies of Particles
4.3 Inelastic Scattering
5 Outlook
References
