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ATR-FTIR spectroscopic analysis of thermally modified wood degraded by rot fungi

Ozgenc O., Durmaz S., Hakki Boyaci I., Eksi-Kocak H.

Drewno : prace naukowe, doniesienia, komunikaty

2018

vol. 61, nr 201

91--105

The resistance of thermally modified oriental spruce, Scots pine, and oriental beech wood samples against fungi is investigated under different temperatures. Thermally modified wood samples are subjected to brown-rot fungi or white-rot fungi. In the control samples, 32-43% of the total mass losses are caused by fungal degradation, but only 0.47-0.78% was caused by the thermally modified wood samples. The changes in the wood cell walls main components, in the wood samples were analysed via attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. The thermally modified and the control wood samples’ spectra after the decay test exhibit different intensities. Thermal modification increases wood’s resistance against decay by removing hemicellulose polymers from the wood cell wall. The resistance against the decay of thermally modified wood is quite high due to the loss of hemicellulose polymers in the wood cell wall. The thermally modified wood structure was also investigated via scanning electron microscopy (SEM) after decay testing. SEM images clearly elucidate that fungal degradation was not effective on the thermally modified wood samples. Conclusively, our study reveals that thermal modification improves some wood’s resistance in Turkey against fungal activity.

Investigation of enzymatic effects on pit membranes using light and scanning electron microscopy

Durmaz S., Yildiz Ü. C., Öztürk M., Serdar B.

Drewno : prace naukowe, doniesienia, komunikaty

2016

vol. 59, nr 198

163--169

Spruce wood is one of the refractory wood species. Pit membranes, which provide liquid flow between the wood cells, have an influence on the permeability of wood. However, these membranes tend to close under the fibre saturation point (FSP), which makes the impregnation process more difficult. In this study, spruce sapwood samples were treated with two different commercial enzymes to improve their permeability. Bioprep 3000 L and Viscozyme L, which are mostly used in the textile industry, are alkaline pectinase enzymes and acidic pectinase enzymes respectively. Following enzymatic treatment, mass losses in the wood samples were observed and the wood samples were analysed with light microscopy (LM) and scanning electron microscopy (SEM). The mass losses of the wood samples were less than 2%. All enzyme treated and untreated wood samples were stained with toluidine blue. The pectin material was coloured red with toluidine blue stain. However, enzymatic treatment caused the loss of red coloration along with the expansion and rupturing of the pit membranes. These results showed that the pit membranes were destroyed.