Antimicrobial Activity and Metabolite Fingerprinting of a Microcolonial Fungal Isolate TD-082 from the Arid Thar Desert, India

Abstract

Aims:: This study aimed at bioprospecting underexplored extreme habitats (Thar desert, India) for novel bio- and chemo-diversity. Background:: Bioactive metabolites from microorganisms, such as fungi from underexplored habitats, serve as basic skeletons of therapeutic agents, including antimicrobials, combating the effect of multidrug resistance of pathogens. Objectives:: The main objectives of the current study are (i) characterization of isolate TD-082 and (ii) metabolite fingerprinting of butanol extract showing antimicrobial compounds. Methods:: In search of novel antimicrobial drugs, a promising microcolonial fungus TD-082, obtained from the Thar Desert, India, was identified by ITS1–5.8S–ITS2 sequencing. Phenotypic characteristics were marked by microscopy. The fungus was investigated for antimicrobial activity against a panel of Gram-positive, Gram-negative bacteria and fungi. Butanol extract that showed the best antimicrobial activity was partially purified; fractions exhibiting antimicrobial activity were pooled and fingerprinted by GC-MS analysis. Results:: Sequencing data indicated that the isolate belonged to Aureobasidium sp. It showed 96% similarity to Aureobasidium iranianum and Kabatiella bupleuri, and 95 % to A. thailandense and A. subglaciale. Microscopy results confirmed that it belongs to Aurebasidium sp. Metabolite fingerprinting showed tentatively ten novel compounds belonging to three major categories, hydrocarbons, fatty acids, and peptides. Conclusion:: The study shows that understudied habitats, such as deserts, can provide skeletons for novel compounds from novel microorganisms. The study can be expanded to other niche habitats with higher chances of identifying more novel bioactive compounds.