Induction of antibiotic production of freshwater fungi using mix-culture fermentation

Antibiotic activities of culture filtrates from twenty filamentous fungi, isolated from wood submerged in tropical freshwater habitats, were tested against a pathogenic strain of Candida albicans. These taxa were fermented separately in liquid medium in pure culture, while another set was fermented with the addition of a fluconazole-sensitive strain of Candida albicans in mix-culture. Fermentation was performed using potato dextrose broth at 25°C for 28 days, with diffuse day light and 240 rpm agitation. Culture filtrates were tested against a fluconazolesensitive and two fluconazole-resistant strains of C. albicans. Anti-fungal activities against strains of C. albicans were not exhibited by any culture filtrates obtained from pure culture fermentation. In mix-culture fermentation, the culture filtrates of an undescribed species of Chloridium and Sporoschisma mirabile produced anti-fungal activities against all three strains of C. albicans tested.