Antimicrobial activity of Aspergillus sp. IBRL MP15 CCL, an endophytic fungus isolated from Swietenia macrophylla leaf against human pathogens

ABSTRACT

@#Aims: Endophytes are microorganisms residing in the living tissues of the host plant and may contribute to their hostplant by producing a plethora of bioactive compounds that provide survival value to the plant. This study aimed toevaluate the antimicrobial activity of Aspergillus sp. IBRL MP15 CCL, an endophytic fungus isolated from Swieteniamacrophylla leaf.Methodology and results: The antimicrobial activity was evaluated with disc diffusion and a colorimetric brothmicrodilution test against 15 organisms comprising of 4 Gram-positive bacteria and 4 Gram-negative bacteria, 4 fungiand 3 yeast. On disc diffusion assay, the fungal extract was shown to inhibit the growth of 7 test bacteria and 3 testyeast. The antibacterial activity was more pronounced with extract from fungal culture with host plant extractsupplementation with significantly larger inhibition zones on all susceptible test microorganisms. The minimal inhibitoryconcentration of the extract ranged from 250 to 4000 μg/mL indicating different level of susceptibility of the testedpathogens against the fungal extract. The killing kinetic study shows that antimicrobial activity of the fungal extract isconcentration dependent and it can act as bactericidal at higher concentration.Conclusion, significance and impact of study The findings of this study suggest that Aspergillus sp. IBRL MP15CCL can be a promising source of antimicrobial agent to be further studied and developed