Examining the Effect of Fermentation Medium on the Antibiotic Activity of Fungal Extracts

Abstract

Fermentation medium can influence the production of bioactive compounds by endophytes, affecting their antimicrobial properties. This study employed a panel of 10 microbial pathogens to examine the antimicrobial activity of extracts derived from 35 endophytes grown in potato dextrose broth (PDB) and malt extract broth (MEB). Factorial ANOVAs showed that extract bioactivity was significantly influenced by growth medium (p < 0.001 for 31 isolates) and pathogen (p < 0.001 for all isolates) and revealed a significant interaction between these factors (p < 0.001 for all isolates). Extracts of isolates grown in PDB generally exhibited greater activity in our bioassays, suggesting that it promotes the production of antimicrobial compounds. However, no consistent trend linked medium-dependant activity to pathogen type, indicating that metabolite production is also influenced by the metabolic ability of individual endophytes. These findings highlight the importance of selecting an appropriate fermentation medium to maximize the bioactivity of endophyte extracts.