Biochemical Profiling
of Extracellular Pigment Metabolites of Aspergillus ustus Strain KUMBASBT-52
Subhakar Akarsh, Hirakannavar Veeranna Sowmya and Basaiah Thippeswamy
Res. J. Chem. Environ.; Vol. 29(10); 40-45;
doi: https://doi.org/10.25303/2910rjce040045; (2025)
Abstract
Filamentous fungi are the mesmerizing glory of an extensive variety of pigments.
Compared to other microorganisms, they produce pigments of different shades as their
secondary metabolites. The study intensified on the cultivation of Aspergillus ustus
strain KUMBASBT-52 under submerged fermentation and extraction of extracellular
pigment metabolites. The extracted pigment metabolites were analyzed via different
analytical techniques. The yield of urochrome-yellow pigment extracted from A. ustus
was 2.39 g/L, which is water-soluble in nature. The UV-Vis analysis exhibited absorption
peaks at 300 nm and 340 nm. The FT-IR analysis transmits the incidence of different
functional groups i.e. 3282cm-1 (Hydroxy group; H-bonded OH stretch), 2921cm-1 (Methylene;
C-H stretch), 2111cm-1 (C≡C Terminal alkyne), 1629 cm-1 (Secondary amine; >N-H bend),
1390cm-1 (Phenol or tertiary alcohol; OH bend), 1233cm-1 (Aromatic phosphates; P-O-C
stretch), 1016 cm-1 (Aliphatic phosphates; P-O-C stretch), 512cm-1 (Polysulfides;
S-S stretch) and 425cm-1 (Aryl disulfides; S-S stretch).
OHR-LC/MS analysis discloses the incidence of 15 bioactive endogenous metabolites,
including yellow pigment metabolites 3-(2-methylpropyl)-octahydropyrrolo[1,2-a]
pyrazine-1,4-dione and 5-Methoxysterigmatocystin. The A. ustus strain KUMBASBT-52
produces urochrome yellow pigments as their endogenous metabolites, which are more
stable than other natural pigments and can be used as a colorant to counter the
carcinogenic synthetic azo dyes.
