Search Results (609)

Lignin is a complex aromatic polymer that constitutes a major fraction of plant biomass and represents a valuable renewable carbon resource. Naturally decaying wood serves as an environmental reservoir of microorganisms capable of degrading lignin. In this study, we isolated and characterized sixteen bacterial strains from decaying Tilia cordata wood using an enrichment culture technique with lignin as the sole carbon source. Taxonomic identification via 16S rRNA gene sequencing revealed microbial diversity spanning the genera Bacillus, Pseudomonas, Stenotrophomonas, and several members of the Enterobacteriaceae family, including Raoultella terrigena isolates. Metagenomic sequencing of the wood substrate revealed an exceptionally rich and balanced bacterial community (Shannon index H′ = 5.07), dominated by Streptomyces, Bradyrhizobium, Bacillus, and Pseudomonas, likely reflecting a specialized consortium adapted to lignin rich late-stage decay. Functional phenotyping demonstrated that all isolates possess ligninolytic potential, evidenced by peroxidase/laccase-type activity through methylene blue decolorization. Dynamic Light Scattering (DLS) and HPLC analyses showed that some isolates, such as Raoultella terrigena MGMM806, effectively depolymerized lignosulfonate into low molecular weight fragments (1.23 nm), while others accumulated intermediate metabolites or completely mineralized the substrate. Growth profiling on monolignol substrates revealed a broad spectrum of catabolic specialization in lignin monomer degradation. The results demonstrate a complex system of metabolic partitioning within a natural bacterial consortium. This collection represents a foundational genetic resource for developing engineered biocatalysts and synthetic microbial communities aimed at the efficient conversion of lignin into valuable aromatic compounds. Full article

The increasing energy crisis demands sustainable functional materials. Wood, with its natural three-dimensional porous structure, offers an ideal renewable template. This study demonstrates that microstructural engineering of wood is a decisive strategy for enhancing magnetothermal conversion. Using eucalyptus wood, we precisely tailored its pore architecture via delignification and synthesized Fe₃O₄ nanoparticles in situ through coprecipitation. We systematically investigated the effects of delignification and precursor immersion time (24, 48, 72 h) on the loading, distribution, and magnetothermal performance of the composites. Delignification drastically increased wood porosity, raising the Fe₃O₄ loading capacity from ~5–6% (in non-delignified wood) to over 14%. Immersion time critically influenced nanoparticle distribution: 48 h achieved optimal deep penetration and uniformity, whereas extended time (72 h) induced minor local agglomeration. The optimized composite (MDW-48) achieved an equilibrium temperature of 51.2 °C under a low alternating magnetic field (0.06 mT, 35 kHz), corresponding to a temperature rise (ΔT) > 24 °C and a Specific Loss Power (SLP) of 1.31W·g⁻¹. This performance surpasses that of the 24 h sample (47 °C, SLP = 1.16 W·g⁻¹) and rivals other bio-based magnetic systems. This work establishes a clear microstructure–property relationship: delignification enables high loading, while controlled impregnation tunes distribution uniformity, both directly governing magnetothermal efficiency. Our findings highlight delignified magnetic wood as a robust, sustainable platform for efficient low-field magnetothermal conversion, with promising potential in low-carbon thermal management. Full article

As an important renewable building material, wood’s flammability significantly limits its application range. This study addresses the environmental pollution issues associated with traditional flame retardants by developing an eco-friendly flame retardant system based on natural biomaterials. Utilizing layer-by-layer self-assembly techniques, sodium phytate, chitosan, sodium alginate, and sodium methyl silicate were sequentially deposited onto the wood surface to construct a multifunctional composite coating. A multifunctional composite coating was constructed on wood surfaces through layer-by-layer self-assembly technology, involving successive deposition of phytic acid sodium, chitosan, sodium alginate, and methyl silicate sodium. Characterization results indicated that the optimized sample WPCSMH achieved a limiting oxygen index of 34.0%, representing a 12% increase compared to untreated wood. Cone calorimetry tests revealed that its peak heat release rate and total heat release were reduced by 57.1% and 25.3%, respectively. Additionally, contact angle measurements confirmed its excellent hydrophobic properties, with an initial contact angle of 111°. Mechanistic analysis reveals that this system significantly enhances flame retardant performance through a synergistic interaction of three mechanisms: gas phase flame retardancy, condensed phase flame retardancy, and free radical scavenging. This research provides a sustainable and innovative pathway for developing environmentally friendly, multifunctional wood-based composites. Full article

Forests play a central role in climate change mitigation by acting as biogenic carbon reservoirs and providing renewable biomass for energy systems. In Portugal, where fire-prone landscapes and species composition dynamics pose increasing management challenges, understanding the carbon storage potential of forest biomass is crucial for designing effective decarbonization strategies. This study provides a comprehensive characterization of the Portuguese forest and quantifies the biogenic carbon stored in live and dead biomass across the main forest species. Species-specific carbon contents, rather than the conventional 50% assumption widely used in the literature, were applied to National Forest Inventory data, enabling more realistic and representative carbon stock estimates expressed in kilotonnes of CO₂ equivalent. While the approach relies on inventory-based biomass data and literature-derived carbon fractions and is therefore subject to associated uncertainties, it provides an improved representation of species-level carbon storage at the national scale. Results show that Pinus pinaster, Eucalyptus globulus, and Quercus suber together represent the largest share of carbon storage, with approximately 300,000 kilotonnes of CO₂ equivalent retained in living trees. Wood is the dominant carbon pool, but roots and branches also account for a substantial fraction, emphasizing the need to consider both above- and below-ground biomass in carbon accounting. In parallel, a bibliometric analysis based on the systematic evaluation of scientific publications was conducted to characterize the evolution, thematic focus, and geographic distribution of global research on forest-based biogenic carbon. This analysis reveals a rapidly expanding scientific interest in biogenic carbon, particularly since 2020, reflecting its growing relevance in climate change mitigation frameworks. Overall, the results underscore both the strategic importance of Portuguese forests and the alignment of this research with the broader international scientific agenda on forest-based biogenic carbon. Full article

This study investigates the Mode II fracture behavior of bamboo–coir–rubber (BCR) hybrid composite panels developed as sustainable alternatives for wood-based panels used in structural applications. The composites were fabricated using alternating bamboo and coir layers within a polypropylene (PP) thermoplastic matrix, with styrene–butadiene rubber (SBR) incorporated as an additive at 0–30 wt.% to enhance interlaminar toughness. Commercial structural plywood was tested as the benchmark. Mode II interlaminar fracture toughness (G_IIc) was evaluated using the ASTM D7905 End-Notched Flexure (ENF) test, supported by optical monitoring to study crack monitoring and Scanning Electron Microscopy (SEM) for microstructural interpretation. Results demonstrated a steady increase in G_IIc from 1.26 kJ/m² for unmodified laminates to a maximum of 1.98 kJ/m² at 30% SBR, representing a 60% improvement over the baseline and nearly double the toughness of plywood (0.7–0.9 kJ/m²). The optimum performance was obtained at 20–25 wt.% SBR, where the laminated retained approximately 85–90% of their initial flexural modulus while exhibiting enhanced energy absorption. Increasing the initial notch ratio (a₀/L) from 0.2 to 0.4 caused a reduction of 20% in G_IIc and a twofold rise in compliance, highlighting the geometric sensitivity of shear fracture to the remaining ligament. Analysis of Variance (ANOVA) confirmed that the increase in G_IIc for the 20–25% SBR laminates relative to plywood and the unmodified composite is significant at p < 0.05. SEM observations revealed rubber-particle cavitation, matrix shear yielding, and coir–fiber bridging as the dominant toughening mechanisms responsible for the transition from abrupt to stable delamination. The measured toughness levels (1.5–2.0 kJ/m²) position the BCR panels within the functional range required for reusable formwork, interior partitions, and transport flooring. The combination of renewable bamboo and coir with a thermoplastic PP matrix and rubber modification hence offers a formaldehyde-free alternative to conventional plywood for shear-dominated applications. Full article

Lignin-based polyurethanes represent a promising strategy for developing more sustainable wood coatings by partially replacing fossil-derived polyols with renewable aromatic biopolymers. In this study, a polyurethane formulated with organosolv lignin (LPU) was synthesized and applied on two non-durable European wood species, Fagus sylvatica L. and Picea abies L., and compared with a commercial fossil-based polyurethane (CPU). Coated samples were evaluated for color stability, gloss evolution, wettability, adhesion, impact and scratch resistance, and biological durability. Accelerated ageing was performed under xenon-light irradiation, while decay resistance was assessed against Gloeophyllum trabeum and Trametes versicolor. Additional tests examined susceptibility to blue-stain fungi and surface morphology via SEM. LPU produced a matte film with intrinsically darker coloration but excellent chromatic stability and minimal gloss variation during ageing. Its initial hydrophobicity was higher on beech and comparable to CPU on spruce. Although CPU exhibited superior adhesion and slightly better mechanical resistance, LPU provided enhanced protection against blue-stain fungi—particularly on spruce—and a more uniform response to decay fungi across wood species. Overall, despite its darker appearance, the lignin-based formulation offered functional protection comparable to the commercial coating, confirming its potential as a viable bio-based alternative for above-ground wood applications. Full article

Lignocellulosic biomass wastes are renewable carbon resources that can be available for conversion into biofuels. There is a growing interest in utilizing a broader range of alternative biomass feedstocks such as agri-crop residues aside from the traditional forest-origin wood residues for fuel pellet production. However, crop residues typically have low and inconsistent fuel quality. This paper investigated the effectiveness of the combined steam explosion and water leaching pretreatment techniques to upgrade the fuel properties of wheat straw. The experimental treatments involved auto-catalyzed steam explosion and acid-catalyzed steam with and without subsequent water leaching. Using steam explosion catalyzed by dilute H₂SO₄ at a low concentration of 0.5 wt%, results showed the highest ash, Si, and Ca removal efficiencies of 82.2%, 91.1%, and 74.3%, respectively. Moreover, there was significant improvement in fuel quality in terms of fuel ratio (0.34) and calorific value HHV (21.9 MJ/kg), as well as a pronounced increase in the comprehensive combustibility index at the devolatization stage, indicating better combustion characteristics. Overall, the results demonstrate that with adequate pretreatment, the quality of agri-pellets derived from wheat straw could potentially be on par with wood pellets that are utilized for heat and power generation and residential heating. To mitigate the dry matter loss due to steam explosion, future studies shall consider using the process effluent to produce biofuel. Full article

To address the contradiction between the widespread prevalence of selenium deficiency and the growing demand for selenium-enriched fruits, this study utilized phosphate tailings (industrial solid waste), wood vinegar (a by-product of forestry processing), biochemical fulvic acid, and alginic acid (renewable biomass resources) to construct an organic–inorganic composite soil selenium activator. This formulation enhances the mobilization of inherent selenium in the soil without relying on exogenous selenium supplementation, thereby improving selenium bioavailability while mitigating the environmental pollution and resource depletion associated with external selenium inputs. Through field experiments, we systematically evaluated the influence of varying activator dosages on soil physicochemical properties, available selenium content, selenium distribution in different citrus organs, and fruit quality. The results demonstrated that the application of the compound activator at 600 g/plant significantly increased (p < 0.05) soil available selenium and fruit selenium content by 21.26% and 21.06%, respectively. During the fruit expansion stage of Sugar Orange, soil available selenium was elevated by 21.8%, which corresponded to a 21.09% increase in fruit selenium content. Regarding fruit quality parameters, Sugar Orange exhibited increases in soluble solids (35.8%), citric acid (20.3%), solid-to-acid ratio (77.8%), and selenium content (223.3%). In Rock Sugar Orange, significant enhancements were observed in soluble solids (46.1%), vitamin C (45.3%), total soluble sugars (73.4%), solid-to-acid ratio (156.6%), and selenium content (69.7%). Structural equation modeling revealed that soil available selenium, soil properties, and selenium content in citrus organs collectively exerted positive regulatory effects on fruit quality. Specifically, juice selenium content showed significant positive correlations with fruit shape index, individual fruit weight, soluble solids content, and solid-to-acid ratio. This strategy achieves the synergistic reuse of industrial solid waste and agricultural biomass resources, offering a green and sustainable pathway to enhance selenium content and quality in citrus fruits. Full article

Having high porosity and biocompatibility, carbon-based materials are promising candidates for tissue engineering applications, particularly as substitutes for biological tissues. This study investigates the growth and viability of osteoblasts on four different activated carbon (AC) materials and correlates biological responses with their physicochemical and morphological properties. Two materials derived from non-renewable sources—AC1, a laboratory-synthesized carbon derived from anthracite, and AC3, a commercial activated carbon (Norit GCN 830) derived from coal—and two commercial activated carbons derived from renewable sources—peat, AC2 (Norit PK1-3), and wood, AC4 (ROX 0.8)—are studied. Results showed that AC1 exhibited the highest porosity (3072 m²/g), with higher phenolic and oxygen-containing surface groups but lower cell viability. In contrast, AC2, AC3, and AC4 displayed lower porosity compared to AC1 (755, 1040, and 1083 m²/g, respectively) and fewer surface phenolic groups but sustained osteoblast proliferation. Notably, AC4 demonstrated superior performance, characterized by regions of fibrous surface, pores in the meso- and microscale range (<50 nm), and enhanced cell viability and proliferation. AC2 also showed favorable results, ranking second for cell growth support. These findings suggest that biomass-derived ACs, particularly AC4 and AC2, provide favorable environments for osteoblast viability and proliferation. AC costs were estimated at 15 to 38 times lower than those for hydroxyapatite and bioceramics, which are widely used for bone cell growth. Thus, ACs made from renewable sources are promising candidates for tissue engineering applications, offering sustainable and effective alternatives for biomedical use. Full article

Softwood-based composites are increasingly used in structural and nonstructural applications owing to their renewability, cost-effectiveness, and favorable strength-to-weight performance. This study applies a systematic literature review and comparative analysis, drawing on approximately 140 sources, to synthesize current knowledge on the physicochemical, mechanical, thermal, and environmental characteristics of engineered wood products derived from softwood species. The intrinsic lignocellulosic composition of softwood, comprising roughly 40%–45% cellulose, 25%–30% hemicelluloses (with mannose as the predominant sugar), and 27%–30% lignin, strongly influences hydrophilicity, stiffness, and thermal behavior. Mechanical properties vary across engineered wood product classes; for example, plywood exhibits a modulus of rupture of 33.72–42.61 MPa and a modulus of elasticity of 6.96–8.55 GPa. Microstructural and spectroscopic analyses highlight the importance of fiber–matrix interactions, chemical bonding, and surface modifications in determining composite performance. Emerging advanced materials, such as scrimber, with densities of 800–1390 kg/m³, and fluorescent transparent wood, achieving optical transmittance above 70%–85%, demonstrate the expanding functional potential of softwood-based composites. Sustainability assessments indicate that coatings, flame-retardants, and adhesives may contribute to volatile organic compound emissions, emphasizing the need for lower-emission, bio-based alternatives. Overall, the findings of this systematic review show that softwood-based composites deliver robust, quantifiable performance advantages and hold strong potential to meet the rising demand for sustainable, low-carbon engineered materials. Full article

Wood is an attractive renewable material, yet its mechanical performance, dimensional stability, and moisture sensitivity limit its use in structural applications. Conventional densification methods often rely on aggressive alkali solutions or resin impregnation, generating environmental concerns and causing excessive cell-wall degradation. In this study a sustainable hydrothermal densification process for oak wood using only a water–ethanol solution in a sealed Teflon-lined autoclave has been investigated and implemented. Treatment at 195 °C for 80 min selectively degraded hemicelluloses and partially reorganized lignin without compromising the cellulose network, followed by hot-pressing at 100 °C under 5 MPa. The hydrothermally densified oak exhibited a significant improvement in stiffness, with a 125% increase in storage modulus relative to untreated wood and a 19.6% enhancement compared to alkali-treated samples. The findings demonstrated that hydrothermal processing is an efficient, low-impact alternative for producing high-performance densified wood suitable for sustainable construction and composite applications. Full article

The transition toward sustainable panel technologies is driving intensive research on binderless boards and self-bonded lignocellulosic composites. Particleboard, an engineered wood composite made by hot pressing wood particles with synthetic adhesives, is among the most widely produced wood-based panels due to cost-effectiveness and versatility. However, pressure on forest-derived raw materials and concern over formaldehyde emissions are accelerating the search for renewable resources and greener routes. Residues and underutilized materials from agro-industrial, food, and forestry sectors (such as cereal straws, sugarcane bagasse, brewer’s spent grain, and fruit-processing by-products) offer a sustainable alternative, enabling waste valorization, lowering environmental burdens, and supporting circular bioeconomy models. Binderless boards, produced without adhesives, exploit natural bonding among lignocellulosic components, including lignin softening, thermoplasticization, and covalent crosslinking during hot pressing. This review adopts a complex network approach to systematically map and analyze the scientific landscape of binderless board production. Using citation-based networks from curated seed papers and their first- and second-degree neighbors, we identify thematic clusters, with cluster “A” as the research core. The examination of this cluster, complemented by word-cloud analysis of titles and abstracts, highlights prevalent raw materials and key research lines, like raw-material sources and lignocellulosic composition, processing parameters, and pretreatment strategies. Based on these findings, brewer’s spent grain is selected as a representative case study for cost analysis. This approach synthesizes the state of the art and reveals emerging directions, research gaps, and influential works, providing a data-driven foundation for advancing self-bonded lignocellulosic composites. Full article

Alkyd resins (ARs) represent a significant development in synthetic polymers, being among the oldest ones and playing a crucial role in numerous applications, especially within the coating sector. The trend is moving towards replacing non-renewable resources in the production of ARs with bio-based alternatives, with the goal of creating more sustainable binder materials as part of the transition to a bioeconomy. 2,5-Furandicarboxylic acid (FDCA) serves as a promising biomass-derived “building block” to replace non-renewable petroleum-derived aromatic diacids and anhydrides in AR synthesis. Various vegetable oils, including sunflower seed (SFO) and linseed oils (LSO), were utilized along with pentaerythritol (P) and glycerol (G) as polyols. FTIR and ¹H NMR spectroscopies were conducted for the verification of alkyd structures. The synthesized ARs were assessed for their physico-chemical properties, including acid value, hydroxyl value, color, density, and viscosity. The performance of the resulting alkyd coatings, which are crucial for their commercial applications, was examined. Key factors such as drying time, hardness, adhesion, wettability, chemical and corrosion resistance, and UV stability were analyzed. All synthesized FDCA-based alkyd coatings demonstrate outstanding adhesion, good thermal stability up to 220 °C, and barrier properties for steel with |Z|_0.02Hz ~10⁶–10⁷ Ohm cm⁻², which render them suitable for the processing requirements of indoor coating applications. The higher temperature at 50% mass loss (T₅₀) for SFO-P (397 °C) and LSO-P (413 °C) as compared to SFO-G (380 °C) and LSO-G (394 °C) indicated greater resistance to thermal breakdown when pentaerythritol was used as a polyol. Replacing glycerol with pentaerythritol in FDCA-based ARs resulted in a viscosity increase of 1.2–2.4 times and an enhancement in hardness from 2H to 3H. FDCA-based ARs exhibited decreased tack-free time, enhanced thermomechanical properties, and similar hardness as compared to phthalic anhydride-based ARs, underscoring the potential of FDCA as a sustainable alternative to phthalic anhydride in the formulation of ARs, integrating a greater proportion of renewable components for wood coating applications. Full article

Wood is a renewable and sustainable environmentally friendly building material. With proper design, it can help buildings achieve lower carbon emissions. However, since wood is a flammable material, its combustion performance in fires has attracted attention. In modern timber structures, glulam is a widely used engineered wood product. Thus, in this paper, glulam specimens made of four kinds of commonly used soft-wood species were used to compare their combustion performance, and the cone calorimeter method was employed. The indicators including time to ignition, heat release rate per unit area, total heat release per unit area, specific extinction area per unit mass, mass of residue, yield of CO and yield of CO₂ were evaluated and compared. The results showed that all the glulam specimens would experience cracking wood and adhesive layer. The time to ignition and peak mass loss rate of the four softwood species in the study was positively correlated with their density. Among these species, Spruce exhibited the highest peak heat release rate and the highest peak CO₂ yield but lowest smoke production, while Douglas fir had a relatively late CO production time and the lowest mass loss percentage, Larch had the lowest heat release rate and total heat release. This study provides fundamental data for the selection of wood structural materials and for future research on wood flame-retardant treatments. Full article

The targeting of environmentally conscious German car drivers through product aesthetics can foster the acceptance of sustainable cars. No guidelines are currently available to designers to create product personality based on environmentally friendly design cues (EFDCs). The aim of this paper was to explore EFDCs for car interiors through bio-based materials. To address this topic, Study 1 examined a collection of bio-based material samples and samples featuring specific colors and reactions to light to determine their potential for the creation of an environmentally friendly product personality. Study 2 built on the implications of the former to examine the contribution of blue as a color and glowing attribute on the development of EFDCs. Wood veneer, cork, and cotton fabric were perceived as sustainable, natural, and renewable by most of the subjects. Brown and white leather was also perceived as sustainable. Moreover, the perception of the naturalness of materials in direct contact with blue light was reduced. Visual texture features for EFDC design are visible fibers or a wooden look. Haptic features include soft, warm, and rough surfaces, while glare, shimmer, a shiny surface, and smoothness should be avoided. The color brown should be considered, while blue, green, and yellow should be avoided. Full article