Quantitative analysis of commercial coating penetration into Fagus crenata wood using X-ray microtomography.

Recent advances in wood treatment include the use of eco-friendly coatings to improve the wood's dimensional stability and appearance. Assessing coating performance during its service life is critical for establishing a knowledge base for product optimization. Numerous approaches, including microimaging, are available for analyzing coating behavior. In addition to conventional microscopic techniques, high-resolution X-ray microtomography is a tool that provides nondestructive imaging of coatings and their substrates. In this study, we performed two-dimensional (2D) and three-dimensional (3D) visualization of tomographic reconstruction images of two coating types, spray and brush, to observe and assess the distribution of several commercial Japanese coating materials in Fagus crenata. X-ray images and plot profiles were used to determine the penetration depths and thicknesses of coatings. Each coated sample was scanned using X-ray microtomography, which allowed successful visualization and quantification of the coating penetration depth. Chemical content and concentration of the coating materials influenced penetration depth and amount.

Long-term behaviour of Cs-137, Cs-133 and K in beech trees of French forests.

In the long-term after atmospheric deposit onto a forest ecosystem, Cs-137 becomes incorporated into the biogeochemical cycle of stable elements and progressively reaches a quasi-equilibrium state. This study aimed at determining to what extent Cs-137 activity distribution in tree vegetation could be predicted from that of stable caesium (Cs-133) and potassium (K), which are known to be stable chemical analogues and competitors for Cs-137 intake in tree organs. Field campaigns that focused on beech trees (Fagus sylvatica L.) were conducted in 2021 in three French forest stands with contrasted characteristics regarding either the contribution of global vs. Chornobyl fallouts, soil or climatic conditions. Decades after Cs-137 fallouts, it was found that more than 80% of the total radioactive inventory in the system remained confined in the top 20 cm mineral layers, while organic layers and beech vegetation (including roots) contributed each to less than 1.5%. The enhanced downward migration of Cs-137 in cambisol than podzol forest sites was presumably due to migration of clay particles and bioturbation. The distribution of Cs-137 and Cs-133 inventories in beech trees was very similar among sites but differed from that of K due a higher accumulation of Cs isotopes in roots (40-50% vs. < 25% for K). The aggregated transfer factor (Tag) of Cs-137 calculated for aerial beech organs were all lower than those reported in literature more than 20 years ago, this suggesting a decrease of bioavailability in soil due to ageing processes. Regarding their variability, Tags were generally lower by a factor 5 at the cambisol site, which was fairly well explained by a much higher value of RIP (radiocesium immobilisation potential). Cs-137 concentrations in trees organs normalized by the soil exchangeable fractions were linearly correlated to those of Cs-133 and the best fit was found for the linear regression model without intercept indicating that no more contribution of the foliar uptake could be observed on long term. Provided that the vertical distribution of caesium concentrations and fine root density are properly measured or estimated, Cs-133 was shown to be a much better proxy than K to estimate the root transfer of Cs-137.

Matrix-free laser desorption/ionization mass spectrometry imaging for rapid evaluation of wood biomass conversion.

RATIONALE: This study overcomes traditional biomass analysis limitations by introducing a pioneering matrix-free laser desorption/ionization (LDI) approach in mass spectrometry imaging (MSI) for efficient lignin evaluation in wood. The innovative acetic acid-peracetic acid (APA) treatment significantly enhances lignin detection, enabling high-throughput, on-site analysis. METHODS: Wood slices, softwood from a conifer tree (Japanese cypress) and hardwood from a broadleaf tree (Japanese beech), were analyzed using MSI with a Fourier transform ion cyclotron resonance mass spectrometer. The developed APA treatment demonstrated effectiveness for MSI analysis of biomass. RESULTS: Our imaging technique successfully distinguishes between earlywood and latewood and enables the distinct visualization of lignin in these and other wood tissues, such as the radial parenchyma. This approach reveals significant contrasts in MSI. It has identified intense ions from ß-O-4-type lignin, specifically in the radial parenchyma of hardwood, highlighting the method's precision and utility in wood tissue analysis. CONCLUSIONS: The benefits of matrix-free LDI include reduced peak overlap, consistent sample quality, preservation of natural sample properties, enhanced analytical accuracy, and reduced operational costs. This innovative approach is poised to become a standard method for rapid and precise biomass evaluation and has important applications in environmental research and sustainable resource management and is crucial for the effective management of diverse biomass, paving the way towards a sustainable, circular society.

UHPLC-ESI-QqTOF Analysis and In Vitro Rumen Fermentation for Exploiting Fagus sylvatica Leaf in Ruminant Diet.

In recent years, animal husbandry has aimed at improving the conditions of livestock animals useful for humans to solve environmental and health problems. The formulation of animal feeds or supplements based on antioxidant plant compounds is considered a valuable approach and an alternative for livestock productivity. Forest biomass materials are an underestimated source of polyphenolic compounds whose sustainable recovery could provide direct benefits to animals and, indirectly, human nutrition. In this context, an alcohol extract from leaves of Fagus sylvatica L. was first investigated through an untargeted ultra-high-performance liquid chromatography-high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) approach. Then, it was fractionated into a fatty acid-rich and a polyphenolic fraction, as evidenced by total lipid, phenol, and flavonoid content assays, with antiradical and reducing activity positively correlated to the latter. When tested in vitro with rumen liquor to evaluate changes in the fermentative parameters, a significant detrimental effect was exerted by the lipid-rich fraction, whereas the flavonoid-rich one positively modulated the production of volatile fatty acids (i.e., acetate, butyrate, propionate, etc.).

Controlling autohydrolysis conditions to produce xylan-derived fibers that modulate gut microbiota responses and metabolic outputs.

Autohydrolysis is used for producing xylan-derived oligosaccharides from lignocellulosic biomass. Although numerous studies report optimized autohydrolysis conditions for various plants, few of these studies correlate process parameters with the resulting structural properties to their impact on intestinal bacterial communities. Thus, to further clarify these relationships, beechwood xylan (BWX)-derived substrates, processed under five conditions, were fermented in vitro by human gut microbiota. Autohydrolysis reduced the mean molecular size and substitutions of BWX. Distinct fermentation kinetics were observed with differing processing of BWX substrates, which correlated with impacts on community species evenness. The relative abundances of Bacteroides, Fusicatenibacter, Bifidobacterium, and Megasphaera within the fermentations varied with processing conditions. While the total short-chain fatty acid concentrations were the same among the treatments, processing conditions varied the extent of propionate and butyrate generation. Autolysis parameters may be an important tool for optimizing beneficial effects of xylan-derived fibers on human gut microbiota structure and function.

Partial exchange of ozone by electron beam irradiation shows better viscosity control and less oxidation in cellulose upgrade scenarios.

Electron beam irradiation (EBI) is an alternative treatment for intrinsic viscosity (IV) control in cellulose pulps, but has never been integrated in full bleaching sequences for comparison to conventional methods. Both eucalyptus kraft (EK) paper pulp and beech sulfite (BS) dissolving pulp were subjected to totally chlorine free (TCF) bleaching sequences comprising either EBI, ozone, or both for IV control. Additionally, effects of EBI on hexenuronic acid (HexA) and xylan were investigated. IV was adjusted to 450-500 mL g-1 and properties including carbonyl content, kappa, brightness, alkali-resistance and sugar composition were compared. Pulps produced with EBI had a higher alkali-resistance, uniformity and less cellulose oxidation. However, the degree of bleaching (DoB) was low without the use of ozone. HexA content in a birch pulp was halved by EBI. Isolated xylans were more resistant to irradiation than cellulose with little decrease of molar masses and moderate oxidation.

Overall Structure Construction of an Intervertebral Disk Based on Highly Anisotropic Wood Hydrogel Composite Materials with Mechanical Matching and Buckling Buffering.

Natural intervertebral disks (IVDs) exhibit distinctive anisotropic mechanical support and dissipation performances due to their well-developed special microstructures. As the intact IVD structure degrades, the absence of function will lead to severe backache. However, the complete simulation for the characteristic structure and function of native IVD is unattainable using current methods. In this work, by overall construction of the two-phase structure of native IVD (extraction of the naturally aligned cellulose framework and in situ polymerization of the nanocomposite hydrogel), a complete wood framework IVD (WF-IVD) is manufactured containing elastic nanocomposite hydrogel-based nucleus pulposus (NP) and anisotropic wood cellulose hydrogel-based annulus fibrosus (AF). In addition to the imitation and construction of the natural structure, WF-IVD also achieves favorable mechanical matching and good biocompatibility and possesses unique mechanical buckling buffer characteristics owing to the aligned fiber bundles. This study offers a promising strategy for the mimicking and construction of complex native tissues.

Electrophysiological Responses of the Beech Leaf-Mining Weevil, Orchestes fagi, to Seasonally-Variant Volatile Organic Compounds Emitted by American Beech, Fagus grandifolia.

The beech leaf-mining weevil, Orchestes fagi, is a common pest of European beech, Fagus sylvatica, and has recently become established in Nova Scotia, Canada where it similarly infests American beech, F. grandifolia. We collected volatile organic compounds (VOCs) emitted by F. grandifolia leaves at five developmental stages over one growing season and simultaneously analyzed them for volatile emissions and O. fagi antennal response using gas chromatography-electroantennographic detection (GC-EAD). Volatile profiles changed significantly throughout the growing season, shifting from primarily ß-caryophyllene, methyl jasmonate, and simple monoterpene emissions to dominance of the bicyclic monoterpene sabinene during maturity. Two VOCs dominant during bud burst, (R)-(+)-limonene and geranyl-p-cymene, may be of biological relevance due to the highly specific oviposition period of O. fagi at this stage though antennal responses were inconclusive. Senescence showed a decrease in blend complexity with an increase in (Z)-3-hexenyl acetate and (Z)-3-hexen-1-ol as well as a resurgence of α-terpinene and geranyl-p-cymene. We present a novel electroantennal preparation for O. fagi. Antennae of both male and female O. fagi responded to the majority of detectable peaks for host volatiles presented via GC-EAD. Females displayed greater overall sensitivities and less specificity to host volatiles and it is hypothesized that this translates to more generalist olfaction than males. It is clear that olfactory cues are important physiologically though their implications on behaviour are still unknown. The results presented in this study provide a baseline and tools on which to connect the complex and highly time-specific phenology of both F. grandifolia and the destructive pest O. fagi through which olfactory-based lures can be investigated for monitoring systems.

Effects of Smoking Temperature, Smoking Time, and Type of Wood Sawdust on Polycyclic Aromatic Hydrocarbon Accumulation Levels in Directly Smoked Pork Sausages.

Smoking is an excellent food preservation method but also a source of contamination of foodstuffs with carcinogenic polycyclic aromatic hydrocarbons (PAHs). Herein we investigated the influence of smoking temperature, smoking time, and type of wood sawdust used as smoke source on PAH levels attained through controlled smoking of pork sausages. Four PAHs (benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[a]pyrene) were monitored, as required by European Commission Regulation 835/2011. PAH concentrations increased continuously both with higher temperatures (55-95 °C) and with longer smoking periods (2-9 h), although the level of benzo[a]pyrene exhibited a tendency to plateau after 6 h. Among seven types of hardwoods tested, plum, alder, and birch yielded PAH concentrations considerably higher than that of commonly used beech, and oak showed similar levels to beech while apple and, to a lesser extent, walnut caused lower levels of sausage contamination. These findings could guide the establishment of good practices in the smoked meat industry.

Lignin Precipitation and Fractionation from OrganoCat Pulping to Obtain Lignin with Different Sizes and Chemical Composition.

Fractionation of lignocellulose into its three main components, lignin, hemicelluloses, and cellulose, is a common approach in modern biorefinery concepts. Whereas the valorization of hemicelluloses and cellulose sugars has been widely discussed in literature, lignin utilization is still challenging. Due to its high heterogeneity and complexity, as well as impurities from pulping, it is a challenging feedstock. However, being the most abundant source of renewable aromatics, it remains a promising resource. This work describes a fractionation procedure that aims at stepwise precipitating beech wood (Fagus sp.) lignin obtained with OrganoCat technology from a 2-methyltetrahydrofuran solution, using n-hexane and n-pentane as antisolvents. By consecutive antisolvent precipitation and filtration, lignin is fractionated and then characterized to elucidate the structure of the different fractions. This way, more defined and purified lignin fractions can be obtained. Narrowing down the complexity of lignin and separately valorizing the fractions might further increase the economic viability of biorefineries.

High porosity with tiny pore constrictions and unbending pathways characterize the 3D structure of intervessel pit membranes in angiosperm xylem.

Pit membranes between xylem vessels play a major role in angiosperm water transport. Yet, their three-dimensional (3D) structure as fibrous porous media remains unknown, largely due to technical challenges and sample preparation artefacts. Here, we applied a modelling approach based on thickness measurements of fresh and fully shrunken pit membranes of seven species. Pore constrictions were also investigated visually by perfusing fresh material with colloidal gold particles of known sizes. Based on a shrinkage model, fresh pit membranes showed tiny pore constrictions of ca. 20 nm, but a very high porosity (i.e. pore volume fraction) of on average 0.81. Perfusion experiments showed similar pore constrictions in fresh samples, well below 50 nm based on transmission electron microscopy. Drying caused a 50% shrinkage of pit membranes, resulting in much smaller pore constrictions. These findings suggest that pit membranes represent a mesoporous medium, with the pore space characterized by multiple constrictions. Constrictions are much smaller than previously assumed, but the pore volume is large and highly interconnected. Pores do not form highly tortuous, bent, or zigzagging pathways. These insights provide a novel view on pit membranes, which is essential to develop a mechanistic, 3D understanding of air-seeding through this porous medium.

Antileukemic Activity of Twig Components of Caucasian Beech in Turkey.

Despite the development of a range of anti-cancer agents, cancer diagnoses are still increasing in number, remaining a leading cause of death. Anticancer drug treatment is particularly important for leukemia. We screened Turkish plants and found the unique antileukemic activity of twig components in Turkish Caucasian beech, selectively inducing apoptosis in leukemia cells. This effect is unique among some kinds of beeches, presumably related to oxidative stress. This study would lead to effective use of discarded material, i.e., twig of beech, and a new anti-leukemic drug based on large tree.

Characterization of an acetyl xylan esterase from the marine bacterium Ochrovirga pacifica and its synergism with xylanase on beechwood xylan.

BACKGROUND: Acetyl xylan esterase plays an important role in the complete enzymatic hydrolysis of lignocellulosic materials. It hydrolyzes the ester linkages of acetic acid in xylan and supports and enhances the activity of xylanase. This study was conducted to identify and overexpress the acetyl xylan esterase (AXE) gene revealed by the genomic sequencing of the marine bacterium Ochrovirga pacifica. RESULTS: The AXE gene has an 864-bp open reading frame that encodes 287 aa and consists of an AXE domain from aa 60 to 274. Gene was cloned to pET-16b vector and expressed the recombinant AXE (rAXE) in Escherichia coli BL21 (DE3). The predicted molecular mass was 31.75 kDa. The maximum specific activity (40.08 U/mg) was recorded at the optimal temperature and pH which were 50 °C and pH 8.0, respectively. The thermal stability assay showed that AXE maintains its residual activity almost constantly throughout and after incubation at 45 °C for 120 min. The synergism of AXE with xylanase on beechwood xylan, increased the relative activity 1.41-fold. CONCLUSION: Resulted higher relative activity of rAXE with commercially available xylanase on beechwood xylan showed its potential for the use of rAXE in industrial purposes as a de-esterification enzyme to hydrolyze xylan and hemicellulose-like complex substrates.

Downscale fermentation for xylooligosaccharides production by recombinant Bacillus subtilis 3610.

The global demand of prebiotics such as xylooligosaccharides (XOS) has been growing over the years, motivating the search for different production processes with increased efficiency. In this study, a cloned Bacillus subtilis 3610, containing the xylanase gene xyn2 of Trichoderma reesei coupled with an endogenous secretion tag, was selected for XOS production through direct fermentation of beechwood xylan. A mixture of XOS with a degree of polymerization ranging from 4 to 6 was obtained, presenting high stability after a static in vitro digestion (98.5 ± 0.2%). The maximum production yield expressed as total XOS per amount of xylan (306 ± 4 mg/g) was achieved after 8 h of fermentation operating under one-time impulse fed-batch. The optimal conditions found were pH 6.0 and 42.5 °C, using 2.5 g/L of initial concentration of xylan increased up to 5.0 g/L at 3 h. Xylopentaose was the major oligosaccharide produced, representing 47% of the total production yield.

Factors of variation in beech forest understory communities on waste heaps left by historical Zn-Pb ore mining.

The species trait-environment relationships in understory vegetation were carried out on metalliferous sites created by historical Zn-Pb mining (S Poland), on which natural revegetation took place. The study sites were 31 small heaps of waste rock covered by an 80-120 year old beech forest. The sites were described in terms of plant coverage, species richness and composition, and the composition of plant traits. Three types of understory communities that were identified were compared for environmental variables and plant parameters. Despite a high concentration of heavy metals in soils, namely Cd, Pb, and Zn, the degree of shading by the tree canopy was the main factor determining variation in understory communities. The understories that developed in low and strong shading were similar to some extent: They had high number of species, and they were characterized by a high proportion of the ancient forest species. The species composition changed substantially with increasing coverage of trees; mixed strategy plants withdrew, while the stress tolerant species became more abundant. The other predictor of community structure was the ratio of Cd to Ca, which was responsible for the decrease of woody plants and the endangered species. This study proved that, in the case of highly complex and productive ecosystems, even with a high degree of contamination with heavy metals, the biotic factors play a primary role.

Oxygen isotopes in tree rings are less sensitive to changes in tree size and relative canopy position than carbon isotopes.

Stable isotope ratios in tree rings have become an important proxy for palaeoclimatology, particularly in temperate regions. Yet temperate forests are often characterized by heterogeneous stand structures, and the effects of stand dynamics on carbon (δ13 C) and oxygen isotope ratios (δ18 O) in tree rings are not well explored. In this study, we investigated long-term trends and offsets in δ18 O and δ13 C of Picea abies and Fagus sylvatica in relation to tree age, size, and distance to the upper canopy at seven temperate sites across Europe. We observed strong positive trends in δ13 C that are best explained by the reconstructed dynamics of individual trees below the upper canopy, highlighting the influence of light attenuation on δ13 C in shade-tolerant species. We also detected positive trends in δ18 O with increasing tree size. However, the observed slopes are less steep and consistent between trees of different ages and thus can be more easily addressed. We recommend restricting the use of δ13 C to years when trees are in a dominant canopy position to infer long-term climate signals in δ13 C when relying on material from shade-tolerant species, such as beech and spruce. For such species, δ18 O should be in principle the superior proxy for climate reconstructions.

Characterization of Klason lignin samples isolated from beech and aspen using microbore column size-exclusion chromatography.

The present study is focused on the separation and characterization of lignin samples isolated by Klason method from European beech (Fagus sylvatica) broadleaf hardwood and European aspen (Populus tremula) broadleaf softwood by size-exclusion chromatography. The separation was carried out using dimethylformamide as major component of the mobile phase and a 3 mm id microbore column packed with hydroxyethyl methacrylate gel, calibrated with polystyrene standards. The influence of mobile phase composition and sample solvent composition on the chromatographic behavior and molar mass distributions was investigated.

Seasonal variation of δ18O and δ2H in leaf water of Fagus sylvatica L. and related water compartments.

The study aims to assess variability in leaf water isotopic enrichment occurring in the field under natural conditions. We focused on seasonal variation and difference between sun-exposed and shaded leaves. Isotopic composition (δ18O, δ2H) of leaf water was monitored in a beech tree (Fagus sylvatica L.) growing in the forest-meadow ecotone together with δ18O (2H) of water compartments which are in close relation to this signal, namely twig and soil water. The sampling was carried out in approximately two-week intervals during five consecutive vegetation seasons. The δ18O (2H) data showed a distinct seasonal pattern and a consistency in relative differences between the seasons and sample categories. Leaf water was the most isotopically enriched water compartment. The leaf water enrichment decreased toward the autumn reflecting the change in δ18O (2H) of source water and evaporative demands. The soil and twig water isotopic signal was depleted against current precipitation as it partly retained the isotopic signature from winter precipitation however the seasonal pattern of soil and twig water followed that of precipitation. No significant differences between sun-exposed and shaded samples were detected. Nevertheless, the observed strong seasonal pattern of isotope composition of leaf, twig and soil water should be taken into account when using leaf water enrichment for further calculations or modeling.

Structural Insights into the Thermophilic Adaption Mechanism of Endo-1,4-ß-Xylanase from Caldicellulosiruptor owensensis.

Xylanases (EC 3.2.1.8) are a kind of enzymes degrading xylan to xylooligosaccharides (XOS) and have been widely used in a variety of industrial applications. Among them, xylanases from thermophilic microorganisms have distinct advantages in industries that require high temperature conditions. The CoXynA gene, encoding a glycoside hydrolase (GH) family 10 xylanase, was identified from thermophilic Caldicellulosiruptor owensensis and was overexpressed in Escherichia coli. Recombinant CoXynA showed optimal activity at 90 °C with a half-life of about 1 h at 80 °C and exhibited highest activity at pH 7.0. The activity of CoXynA activity was affected by a variety of cations. CoXynA showed distinct substrate specificities for beechwood xylan and birchwood xylan. The crystal structure of CoXynA was solved and a molecular dynamics simulation of CoXynA was performed. The relatively high thermostability of CoXynA was proposed to be due to the increased overall protein rigidity resulting from the reduced length and fluctuation of Loop 7.

Five-year volume growth of European beech does not respond to ozone pollution in Italy.

A unique database of stand volume growth, estimated as periodic annual volume increment (in m3 ha-1 per year over the period 2001-2005) from 728 European beech (Fagus sylvatica L.) sites distributed across Italy, was used to assess the effects of ambient ozone (O3), expressed as annual average (M24), accumulated exposure above a 40 ppb hourly threshold (AOT40), and total stomatal ozone flux (POD0). Growth data were from the National forest inventory of Italy, while climate data and ozone concentrations were computed by the WRF and CHIMERE models, respectively. Results show that the growth increased with increasing solar radiation and air temperature and decreased with increasing number of cold days, while effects of soil water content and O3 were not significant. In contrast, the literature results suggest that European beech is sensitive to both drought and O3. Ozone levels resulted to be very high (48 ppb M24, 51,200 ppb h AOT40, 21.08 mmol m-2 POD0, on average) and thus able to potentially affect European beech growth. We hypothesize that the high-frequency signals of soil water and O3 got lost when averaged over 5 years and recommended finer time-resolution investigations and inclusion of other factors of variability, e.g., thinning, tree age, and size.