Characterization of the decay process of Scots pine caused by Coniophora puteana using NMR and MRI

Abstract

Wood decay is an economically significant process, as it is one of the major causes of wood deterioration in buildings. In this study, the decay process of Scots pine (Pinus sylvestris) samples caused by cellar fungus (Coniophora puteana) was followed by nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) methods. Altogether, 30 wood sample pieces were exposed to fungus for 10 weeks. Based on the decrease of the dry mass, the samples were categorized into three classes: decomposed (mass decrease 50–70%), slightly decomposed (10–50%), and nondecomposed (<10%). MRI made it possible to identify the active regions of fungus inside the wood samples based on the signal of free water brought by the fungus and arisen from the decomposition of wood carbohydrates. MRI implies that free water is not only created by the decay process, but fungal hyphae also transports a significant amount of water into the sample. Two-dimensional 1H T1-T2 relaxation correlation NMR measurements provided detailed information about the changes in the microstructure of wood due to fungal decomposition. Overall, this study paves the way for noninvasive NMR and MRI detection of fungal decay at early stages as well as the related structural changes.

Enhanced water uptake in the longitudinal direction by shiitake mycelium in shiitake cultivation logs: increase in effective diffusion coefficient based on mass of liquid water uptake

“…Water molecules existing in wood that is adequately supplied with liquid water are roughly classified into two types: "bound water" and "free water" (Brownstein 1980;Gezici-Koç et al 2017;Cai et al 2020;Hiltunen et al 2020). Since bound water is tightly bound to molecules in the cell walls and fibers composed of mainly cellulose, hemicellulose and lignin, the T 2 relaxation time constant of the hydrogen atoms in the bound water is shorter than 1 ms (Müller et al 2001;Gezici-Koç et al 2017;Cai et al 2020;Hiltunen et al 2020). On the other hand, since free water existing in the voids such as cell lumens and vessels can move relatively freely, the T 2 relaxation time constant of free water is longer than 1 ms.…”

“…However, if wood contains liquid water, the water inside the wood can be visualized by MRI (Hall and Rajanayagam 1986;Chang et al 1989;Wang and Joseph 1989;Bucur 2003;Kuroda et al 2006;Hameury and Sterley 2006;Zhou et. al 2018;Hiltunen et. al.…”

“…The origin of the NMR signal that reconstructs the MR image is the hydrogen atoms in water molecules. The NMR signal emitted from the hydrogen atoms contained in the many water molecules constituting wood tissue such as cellulose or hemicellulose cannot be measured under the MRI measurement condition of echo time TE = 12 ms since the T 2 relaxation time constant of the hydrogen atoms is much shorter than 1 ms (Müller et al 2001;Gezici-Koç et al 2017;Cai et al 2020;Hiltunen et al 2020). However, if wood contains liquid water, the water inside the wood can be visualized by MRI (Hall and Rajanayagam 1986;Chang et al 1989;Wang and Joseph 1989;Bucur 2003;Kuroda et al 2006;Hameury and Sterley 2006;Zhou et.…”

Leachability and Decay Resistance of Wood Polyesterified with Sorbitol and Citric Acid

“…SCA modification increased the non-freezing moisture content calculated with Equation (3). Other wood modifications, such as acetylation and thermal modification, have been shown to reduce non-freezing moisture content determined with LFNMR [49,50,78]. Dieste et al [40] determined the non-freezing moisture content of DMDHEU modified wood and found the non-freezing moisture content was not significantly different from unmodified wood.…”

Analysis of water content in wood material through 1D and 2D 1H NMR relaxometry: Application to the determination of the dry mass of wood

“…Regarding lignocellulosic materials, NMR relaxometry has been also used for studying biomass-water interactions, measuring water retention values (WRVs), understanding biomass recalcitrance and high solid effects [12][13][14][15]. Two main experiments are used in literature: (i) 1D T 2 NMR relaxometry, mainly due to its short experimental time and its possibility to distinguish bound and free water and (ii) 2D T 1 T 2 correlation NMR relaxometry, as it significantly improves resolution and gives physical and chemical information on the samples [16][17][18][19]. For instance, the latter enables the resolution of two types of bound water in the wood cell walls.…”