OTIMIZAÇÃO DA PRODUÇÃO DE COMPOSTOS ANTIBACTERIANOS A PARTIR DO FUNGO ENDOFÍTICO Penicillium cataractarum 5IP2F4

Abstract

Endophytic fungi are an important source of secondary metabolites with potential pharmacological applications, standing out as promising candidates in the search for new antimicrobial compounds. Penicillium cataractarum is a species that remains poorly explored but it has shown relevant results in preliminary antibacterial studies. In this context, the present work aimed to investigate and optimize the production of antibacterial metabolites from the endophytic strain P. cataractarum 5IP2F4, isolated from Bromelia balansae collected in the s Pantanal of Mato Grosso do Sul (Brazil). The OSMAC (One Strain Many Compounds) strategy was applied by varying liquid culture media in order to modulate biosynthetic pathways and expand the chemical diversity produced by the strain. Antibacterial activity was assessed by broth microdilution assays, and chemical analyses of the extracts were performed using HPLC-DAD-MS and GC-MS. Variations among the culture media significantly influenced mycelial growth and the chemical profile of the extracts, resulting in differences in extract yields. Kinetic analysis indicated that day 22 corresponded to the point of highest accumulation of extracellular metabolites, reflected by the intensification of the four major annotated compounds, all classified as diketopiperazines. GC-MS analysis revealed marked variation among the media, with ergosterol predominating in the hexane fractions from mycelial extracts obtained in PDB and YPD cultures, while CZA medium favored the production of unsaturated fatty acid esters, especially methyl linoleate and methyl oleate. Regarding antibacterial inhibition, although none of the extracts displayed significant activity against Escherichia coli (ATCC 14458), the supernatant extract obtained from Czapek medium (EBsob–CZA) inhibited 68% of Staphylococcus aureus ATCC 25904 growth at 1 mg/mL. The findings reinforce that P. cataractarum 5IP2F4 possesses a versatile metabolome strongly dependent on culture conditions, confirming the importance of the OSMAC strategy as a tool for activating biosynthetic pathways and expanding accessible chemical diversity. Overall, this study contributes to the understanding of the biosynthetic potential of P. cataractarum and highlights its relevance as an alternative source of metabolites with antibacterial activity, particularly against pathogens of public health importance.