Melanin, a widespread
pigment found in many taxa, is widely recognized
for its high refractive index, ultraviolet (UV) protection, radical
quenching ability, metal binding, and many other unique properties.
The aforementioned characteristic traits make melanin a potential
candidate for biomedical, separation, structural coloration, and space
applications. However, the commercially available natural (sepia)
and synthetic melanin are very expensive, limiting their use in various
applications. Additionally, eumelanin has been the primary focus in
most of these studies. In the present study, we demonstrate that melanin
can be extracted from the pathogenic black knot fungus
Apiosporina morbosa
with a yield of ∼10% using
the acid–base extraction method. The extracted melanin shows
irregular morphology. Chemical characterization using X-ray photoelectron
spectroscopy, infrared spectroscopy, and solid-state nuclear magnetic
resonance spectroscopy reveals that the melanin derived from black
knots is the less explored nitrogen-free allomelanin. Additionally,
the extracted melanin shows broadband UV absorption typical of other
types of melanin. Because of the wide availability and low cost of
black knots and the invasive nature of the fungus, black knots can
serve as an alternative green source for obtaining allomelanin at
a low cost, which could stimulate its use as an UV light absorber
and antioxidant in cosmetics and packaging industries.