Antimicrobial activities of fungus comb extracts isolated from Indomalayan termite (Macrotermes gilvus Hagen) mound

Incorporating antimicrobial components into food packaging materials can prevent microbial contamination. Fungus
combs could be an alternative source of natural antimicrobial agents. In this study, n-hexane, ethyl acetate, methanol,
and water extracts were obtained from fungus combs isolated from Indomalayan termite (Macrotermes gilvus Hagen)
mound. Their antibacterial and antifungal activities against food spoilage microorganisms including Escherichia coli
ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Aspergillus favus, and Aspergillus niger were evaluated by Kirby–Bauer disc difusion and microdilution. Results showed that ethyl acetate extract
formed the largest diameter inhibition zone for all tested bacteria and fungi, exhibited antibacterial activity against
all tested bacteria with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)
values of 0.39 and 0.78 mg/mL, respectively, and suppressed A. favus and A. niger with an MIC value of 0.78 mg/mL.
This extract contained guaiacol and syringol, which were predicted as the main antimicrobial components in fungus
comb. n-Hexane extract only inhibited Gram-positive bacteria. S. aureus ATCC 25923 was the most sensitive to all the
extracts, and A. favus was more sensitive than A. niger. All these fungus comb extracts exhibited antimicrobial activity
against E. coli ATCC 25922, P. aeruginosa ATCC 27853, S. aureus ATCC 25923, A. favus, and A. niger. This study revealed
that fungus comb extracts, especially ethyl acetate, could be considered as a new antimicrobial agent.