A comparative characterization study between fungal and bacterial eumelanin pigments

Area of Science:

• Biochemistry
• Materials Science
• Microbiology

Background:

• Melanins are complex natural pigments found across diverse taxa.
• Interest in melanins is growing due to their versatile properties in medicine, cosmetics, and electronics.
• Eumelanins, a common type, are biopolymers derived from phenolic and indolic compounds.

Purpose of the Study:

• To characterize extracellular eumelanin pigments from bacterial and fungal sources.
• To analyze the structural and nanostructural properties of these eumelanins.
• To molecularly identify the microorganisms producing these eumelanin pigments.

Main Methods:

• Spectrometric analysis: FT-IR, XRD, NMR, UV-vis.
• Microscopic analysis: Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM).
• Molecular characterization: 16S rDNA and 18S rDNA sequencing.

Main Results:

• XRD analysis revealed a characteristic peak around 22° for purified eumelanins.
• NMR spectra showed signals in both aromatic and aliphatic regions for all pigments.
• AFM and SEM provided insights into the nanostructure of the biopolymers.
• Microorganisms identified as *Streptomyces* and *Aspergillus* species were molecularly characterized.

Conclusions:

• The study provides a comprehensive characterization of bacterial and fungal eumelanins.
• The findings contribute to understanding the complex structure and properties of these natural pigments.
• Molecular identification of producer strains facilitates further research and potential biotechnological applications.