Composting as gold mine for bioprocess: Bioprospecting biomolecules- producing filamentous fungi

Composting is a cost-effective and environmentally friendly strategy for the treatment of organic waste that can result in the production of nutrient-rich mature compost. Throughout the composting process, diverse microbial communities play key roles in the degradation of complex organic compounds, including cellulose, hemicellulose, and lignin, through the secretion of several compounds such as hydrolytic enzymes. In addition to their enzymatic potential, some filamentous fungi involved in composting are also capable of producing bioactive secondary metabolites, such as natural colorants with biotechnological relevance. Given this context, the present study aimed to isolate and evaluate filamentous fungi from different composting phases for their ability to produce enzymes and natural colorants. Fungi were collected using the serial dilution technique and cultured on Potato-Dextrose Agar (PDA) medium. Fungal isolates were purified, coded systematically, and cultivated to evaluate their enzyme and colorant production under both solid and submerged culture conditions. Approximately 70% and 93% of the fungal isolates showed amylase and cellulase production, respectively. Only one fungal isolate produced a red diffusible colorant in both cultivation systems and was identified as Talaromyces sp. (C1I3). These results highlight the composting process as a promising source of fungal strains capable of synthesizing valuable biomolecules, reinforcing their potential for biotechnological applications in areas such as natural additives (colorant) and industrial biocatalysts (enzymes).