Genetic validation and spectroscopic detailing of DHN-melanin extracted from an environmental fungus

- DNA was extracted by a standardised protocol that can be adapted for environmental and clinically isolated fungi.
- The presence of genes was used to identify the type of melanin.
- Physico chemical characterization of the melanin extracted was performed.
- UV-Vis and IR spectra were used to confirm the type of melanin. Further, the chemical moieties were substantiated using 13C solid state NMR spectroscopy.

Accurate characterization of melanin using analytical methodologies has proved to be difficult due to its heterogeneity, insolubility in wide pH and broad range of solvents. The present study was undertaken to characterize melanin extracted from an environmental Aspergillus fumigatus AFGRD105 by studying its genes, chemical properties and spectral data. A gene based approach to confirm the type of melanin carried out indicated the extracted melanin to be of the dihydroxynaphthalene type. On comparison with synthetic melanin, UV-Vis and IR spectra of the extracted melanin revealed characteristic peaks that can be further used for confirmation of DHN-melanin extracted from any source. Solid state 13C NMR spectroscopy established the presence of the hydroxyl-naphthalene moiety and validated the results obtained by genetic analysis. The correct assignment of the observed spectral frequency characteristic of functional groups can be further adapted in future works that deal with binding capacities and biomolecule systems involving melanin.