In the present study, pectinase was produced by local fungal isolate, Aspergillus niger LFP-1 grown on pomelo peels as a sole carbon source under solid-state fermentation (SSF). The purification process begins with the concentration of crude enzyme using ammonium sulfate precipitation and followed by purification using anion-exchange column chromatography (DEAE-Sephadex) and subsequently using gel filtration column chromatography (Sephadex G-100). On the other hand, the molecular weight of the purified enzyme was determined through SDS-PAGE. The findings revealed the crude enzyme was purified up to 75.89 folds with a specific activity of 61.54 U/mg and the final yield obtained was 0.01%. The molecular mass of the purified pectinase was 48 kDa. The optimum pH and temperature were 3.5 and 50°C, respectively. This enzyme was stable at a range of pH 3.5 to 4.5 and a relatively high temperature (40°C–50°C) for 100 min. The Km and Vmax were found to be 3.89 mg/mL and 1701 U/mg, respectively. Meanwhile, pectin from citrus fruit and the metal ion (Co2+) were the best substrate and inducer to enhance pectinase yield, respectively.

Background: The emergence of multidrug-resistant pathogens associated with biofilm formation can cause life-threatening infections to humans. Therefore, the present study aims to evaluate the effects of the fungal extract of Lasiodiplodia pseudotheobromae (L. pseudotheobromae) Industrial Biotechnology Research Laboratory (IBRL) OS-64 on bacterial cells and the biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA). Methods: Broth microdilution and semi-quantitative adherence assays were conducted to determine the anti-biofilm activity of the fungal extract. Light and scanning electron microscopy (SEM) analyses were performed to observe the effect of the fungal extract on biofilm formation by MRSA. Results: The transmission electron microscopy (TEM) microphotographs showed that the bacterial cells were severely damaged upon 24 h exposure to the extract and displayed several symptoms such as cell shrinkage and breakage. Meanwhile, results from the antibiofilm study indicated the extract attenuated the initial and preformed biofilms of MRSA by 80.82% and 61.39%, respectively. The initial biofilm was more sensitive to the extract compared to the pre-formed biofilm, as evidenced by the light microscopy and SEM observations that demonstrated more severe bacterial cell damage on the initial biofilms compared to pre-formed biofilms. Conclusion: The ethyl acetate extract of L. pseudotheobromae IBRL OS-64 significantly inhibited bacterial cells growth and eliminated biofilm formation by MRSA.

Endophytic fungi are known as potential novel compound producers with promising antimicrobial activities. Hence, the present study aimed to investigate the possible bioactive compounds present in the ethyl acetate extract of Lasiodiplodia pseudotheobromae IBRL OS-64. The ethyl acetate extract exhibited significant antibacterial activity against both Gram-positive and Gram-negative bacteria in disc diffusion assay. Thin-layer chromatography (TLC) was performed with chloroform, acetone and ethyl acetate (1:2:1, respectively) used as a solvent system and nine spots with diverse polarities were obtained. The TLC chromatogram with the active spot was localized with bioautography assay and the finding revealed that the dark spot with an Rf value of 0.5882 showed good antibacterial activity against all test bacteria. The fraction F5 exhibited promising antibacterial activity upon partial purification of dark spot via column chromatography and the GC-MS analysis of fraction F5 resulted in the detection of a major compound, 2-Benzenedicarboxylic acid, mono (2-ethylhexyl) ester with 90% matching factor. Thus, this compound may greatly contribute to the antibacterial activity of the fraction and has the potential to be developed as an antibiotic. The findings indirectly indicate that fungal endophytes from the medicinal plant could be a potential candidate for bioactive compounds with pharmaceutical properties.

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