Biological Potential of Fungal Endophyte K5A Associated with Nudibranch
Harwoko Harwoko(1*), Nuri Rahmadani(1), Hapsari Dinda Meutiara(1), Putri Khaerani Cahyaningrum(1), Ira Handayani(2), Hasyrul Hamzah(3)

(1) Department of Pharmacy, Universitas Jenderal Soedirman, Purwokerto, Central Java 53123, Indonesia
(2) Research Center for Applied Microbiology, National Research and Innovation Agency (BRIN), Cibinong Bogor, West Java 16911, Indonesia
(3) Faculty of Pharmacy, Universitas Muhammadiyah Kalimantan Timur, Samarinda, Kalimantan Timur 75124, Indonesia

Abstract

Background: Antimicrobial resistance is a global health challenge, with biofilm formation playing a key role in bacterial persistence.
Purpose: This study investigated a nudibranch-associated fungus K5A, for its antibacterial and antibiofilm properties.
Methods: A single pure K5A isolate was identified through morphological and molecular (Sanger sequencing) analyses. The fungus was cultured on solid rice medium and then extracted using ethyl acetate to test its antibacterial activity against both Gram-positive and Gram-negative bacteria. Moreover, antibiofilm activity was assessed against Staphylococcus aureus and Pseudomonas aeruginosa in the mid-phase of biofilm formation (24 h) using the microdilution method.
Results: A fungus K5A was closely identified as Aspergillus sp. However, the 1% crude extract exhibited no pronounced antibacterial activity. In contrast, this extract revealed potential antibiofilm activity against S. aureus and P. aeruginosa in the mid-phase of biofilm formation. Antibiofilm activity towards both bacteria was comparable to that of the positive control.
Conclusion: This finding highlights Aspergillus sp. K5A as a promising source of antibiofilm candidates, although it does not align with its antibacterial effects. Further study is needed, including investigation using scanning electron microscopy and evaluation in the longer phases.

Keywords: Antibacterial, antibiofilm, antimicrobial resistance, Aspergillus, endophytic fungus

Topic: Pharmaceutical Sciences and Clinical Pharmacy