Variation in the chemical composition of Amazonian woods submitted to decay fungi

Abstract

As a biological material, wood is susceptible to the action of xylophagous agents, which alter its physical and chemical properties, with the decay fungi standing out among these, causing damage and changing the chemical composition of the wood, as a result of the metabolism of its components. This study evaluated changes of the main chemical components of four Amazonian wood species after the attack of two decay fungi by means of gravimetric chemical analysis and mid-infrared spectroscopy. The chemical analyzes allowed distinguishing the action mechanisms of the fungi in relation to the chemical components of the wood. Overall, after the action of the Gloeophyllum trabeum fungus (brown rot), a reduction in the holocellulose proportion was observed, while for Trametes versicolor (white rot) it was a reduction of lignin. With the principal component analysis (PCA) results, it was possible to separate the treatments per wood, by using its mass loss and chemical components. It was also possible to differentiate the decay fungi by using the absorbance band intensities of the mid-infrared spectrum. As a conclusion, the mid-infrared spectroscopy has proved to be a useful tool in distinguishing classes of decay fungi. Further researches on this may contribute to create a more robust database for the identification of decay fungi action in wood.