Co-cultivation strategies with different microbial partners for novel metabolite discovery

The global rise in antimicrobial resistance (AMR) and limitations of existing antibiotics as a result necessitate the exploration of alternative sources of bioactive compounds. Endophytic fungi associated with medicinal plants represent a promising reservoir of secondary metabolites with therapeutic potential. This study investigates the bioactive potential of endophytic fungi isolated from Bryophyllum pinnatum L and Sansevieria trifasciata P, with emphasis on enhancing metabolite production through co-cultivation. Endophytic fungi were isolated, purified, and cultured under monoculture and co-culture conditions using rice and potato media. Crude extracts were obtained using solvent extraction and evaluated for antimicrobial and antioxidant. Antimicrobial assays were conducted against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. Antioxidant activity was assessed using DPPH and FRAP assays. Results demonstrated that culture conditions significantly influenced metabolite expression. Co-culture systems, particularly in rice medium, exhibited enhanced antimicrobial activity compared to monocultures. Extracts showed selective activity, with greater efficacy against Gram-positive bacteria such as S. aureus, while P. aeruginosa showed resistance. Notably, co-culture extracts (e.g., F. oxysporum + C. lunata) exhibited improved activity against C. albicans and E. coli, suggesting synergistic or induced biosynthetic responses. Antioxidant activity was generally moderate but significantly improved in co-culture systems, indicating activation of silent metabolic pathways. The findings highlight the role of interspecies interaction and substrate composition in modulating fungal secondary metabolism. Endophytic fungi from B. pinnatum and S. trifasciata, particularly Fusarium oxysporum, Hypoxylon griseobrunneum, and Curvularia lunata, demonstrate promising potential as sources of bioactive compounds, Penicillum oxalicum, Curvularia chiangmaiensis and Diaportha sp also isolated showed Co-cultivation significantly enhances metabolite production, supporting its application as a cost-effective strategy for drug discovery.