CHARACTERISATION OF PALM PYROLIGNEOUS ACID AND ITS EFFECTIVENESS AS ANTIFUNGAL AGENT FOR OIL PALM TRUNK

Abstract

Pyroligneous acid (PA) is a by-product from carbonisation of palm kernel shell (PKS) with more than 200 organic compounds, including phenolic and organic acids. The purpose of this study was to characterise and evaluate the effectiveness of PA to protect oil palm trunk (OPT) against fungal attack. Wood vinegar was produced at four carbonisation temperatures (i.e., 500°C, 600°C, 700°C and 800°C). The chemical properties of PA were measured using Fourier transform infrared (FTIR) spectroscopy and gas chromatography-mass spectroscopy (GC-MS). The antifungal assay of PA from carbonisation at 600°C was applied on OPT against a white-rot fungus, Trametes versicolor, and a brown-rot fungus, Fomitopsis palustris. The effectiveness of PA against both fungi was evaluated by soaking OPT in the PA solution for 24 hr at 25°C, followed by exposure to the media containing the fungi, as stipulated in ASTM D-4455 standard. The lowest mean weight loss (9.33%) was obtained after eight weeks of exposure. The OPT-PA-treated specimen was highly resistant to the growth of T. versicolor. It was assumed that acid and phenolic components contributed to enhanced growth control of fungi, as indicated from the GC-MS results. The chemical compositions of PA proved that the antifungal activities could be controlled using a high concentration of PA.