Bacterial infection is a health problem that keeps increasing, yet antimicrobial resistance (AMR) is a major
public health threat in the 21st century. Naturally produced secondary metabolites have been used as
sources of new drug discovery, including new antibacterial agents. Diaporthe, a genus of dark septate
endophyte (DSE) fungi, is known to have potential antibacterial activity. This paper aims to investigate the
antibacterial activity of Diaporthe pandanicola TM1 against Escherichia coli and Streptococcus aureus and
isolate the compounds contained in the fungi. The liquid culture of D. pandanicola is first centrifuged to
obtain its biomass and media. The biomass was extracted by maceration with methanol as a solvent and
the media was extracted by liquid-liquid extraction (LLE) using ethyl acetate. Then, fractionation of the
media extract was done using vacuum liquid chromatography (VLC) which produced five fractions.
Antibacterial susceptibility test was then done on extracts and fractions using agar disk diffusion method.
Lastly, isolation and purification was done to the dominant fraction using radial chromatography. The
result from the antibacterial susceptibility test shows that the extract and fraction do not produce any
zone of inhibition, indicating no antibacterial activity towards tested bacteria. The isolation and
purification process yielded 4.5 mg of pure isolate which was not tested for antibacterial activity due to
no promising activity of the extracts and fractions that was previously observed. Despite the weak
antibacterial properties, the isolation aimed to obtain a pure dominant compound for further studies,
such as structure elucidation, testing for other biological activities, or discovering potential synergies with
other compounds.