Volume 21 Issue 3

Vacuum pretreatment, valued for low energy use and sustainability, has attracted attention in wood dyeing. Using an orthogonal experimental approach, the vacuum pretreatment parameters were optimized for Chinese fir, poplar, and white oak veneers. The ideal circumstances were as follows: Chinese fir −0.08 MPa/90 °C/30 min; poplar −0.09 MPa/90 °C/30 min; and white oak −0.09 MPa/90 °C/90 min, based on color difference (∆E*), mass change, and water absorption weight rise. After the veneers were dyed with a camphor fruit pigment solution, the effect of the pretreatment on the microstructural alterations and macroscopic dyeing performance was assessed. The dye penetration depth and absorption rose by 60% to 95% following pretreatment. Reflectance spectra and ∆E* values showed that the treated samples had more consistent and vibrant coloring. Additionally, there was a minor improvement in the lightfastness of all three wood types. According to microstructural research, the pretreatment increased the distribution of binding sites for interactions between dye molecules and the wood matrix by partially opening the vessel components and cell wall structures. In summary, vacuum pretreatment significantly improved the dye’s homogeneity and fixing in wood veneers, offering a practical and environmentally friendly method of effective wood processing.

A two-step management strategy was evaluated for rapid feeding suppression and colony elimination of termites (Reticulitermes speratus) infesting wooden cultural heritage structures (WCHS). A large-scale (15-m foraging distance) arena system with a colony size of 10,000 termites — consisting of a main nest, a shelter, and fipronil-treated wood units connected by foraging tunnels — was utilized to compare an untreated control group, a fipronil-treated group, a bistrifluron-treated group, and a combined treatment (F+B) group. In the fipronil-treated group, feeding on the treated wood rapidly decreased, demonstrating rapid reduction in wood consumption on treated wood; however, colony survival persisted and feeding activity was redistributed toward the untreated shelter zone. In contrast, the bistrifluron-treated group ultimately achieved complete colony collapse, although feeding on both the treated wood and shelter wood continued during the elimination process. The combined treatment rapidly suppressed feeding on the treated wood and completely eliminated the colony within 10 weeks through subsequent bait consumption. Furthermore, the combined treatment significantly reduced the feeding redistribution toward untreated wood sources that were observed in the fipronil-only group. These findings suggest that the combined application of fipronil-treated wood and CSI bait can provide both immediate protection for WCHS members and long-term colony elimination, offering a promising approach that warrants further field validation as an efficient termite management strategy for WCHS.

Joints are important components of wooden structures that provide continuity to wood and wood products. In this study, a finger joint with two finger lengths of 5 and 10 mm was investigated with two adhesives: epoxy and polyvinyl acetate reinforced with cellulose nanocrystals (CNC) and nanoclay at three levels of 0%, 0.4%, and 1.5% using the free bending vibration method in a free-ended beam on a plywood. The results indicated that except for vibration damping, the values ​​at the 10 mm joint length were significantly higher at the 95% confidence level. The effect of CNC was also significantly higher than that of nanoclay at the 95% confidence level. Both nano-based adhesives at 1.5% had significantly better results. Epoxy adhesive also had significantly better results than polyvinyl acetate adhesive. Overall, the joint with a 10 mm finger length jointed with epoxy adhesive and reinforced with 1.5% CNC yielded the best results.

The feeding activity of the subterranean termite Reticulitermes speratus was investigated under different temperature conditions. Wood consumption and microwave signal intensity increased with temperature and were highest at 21 to 27 °C. Feeding activity decreased above 30 °C, and termite movement was also reduced at high temperatures. These changes may be related to thermal stress and reduced activity of hindgut symbiotic protozoa. Field temperature data collected from wooden cultural heritage buildings and surrounding soil environments showed that temperatures suitable for termite activity were maintained from spring to autumn in many regions of Korea. Seasonal temperature changes were also associated with the overwintering and reproductive characteristics of R. speratus. Based on these results, installation of chitin synthesis inhibitor (CSI) bait systems in early spring may improve termite control before peak summer activity. The results of this study may be useful for termite monitoring and management of wooden cultural heritage buildings.

Wood vinegar (WV) produced via biomass pyrolysis, presents an organic alternative for weed control. This study aimed to: (i) determine the physical properties and elemental composition analysis of WV, and (ii) evaluate the efficacy of WV from wood residues of Gmelina arborea produced with slow pyrolysis to control weeds under a Cupressus lusitanica Christmas tree plantation. WV was dissolved in water at 75% and applied in doses of 1000, 3000 and 5000 L ha^-1, with the synthetic herbicide Basta® (glufosinate-ammonium) as a control. The efficacy of WV on weeds was visually evaluated from 0 (not injury) to 100 (plant death). Treatments with 3000 and 5000 L ha⁻¹ doses caused rapid desiccation of grass and broadleaf weeds, achieving 85 to 88% visual injury. Biomass reduction of 40% can be obtained when WV is applied at high doses (3000 and 5000 L ha^-1) on mature grass-dominated weeds, showing effects comparable to synthetic herbicide. While WV effectively reduced weed biomass, it was insufficient to completely remove mature weeds.

The development of sustainable packaging materials is becoming increasingly important to address environmental issues. In this context, all-cellulose composites (ACCs) represent a potential alternative to traditional composite materials. ACC consists entirely of cellulose and has significantly improved mechanical and barrier properties compared to paper. For packaging applications, the potential for material recycling and biodegradability are of great interest. However, these topics have so far been insufficiently addressed. In this study, the biodegradability of paper and different ACCs is compared. In addition, studies on the recyclability of the material were carried out. It was demonstrated that ACC is biodegradable. The rate of biodegradation depended on the parameters during the production process. Self-produced ACC was degraded at a rate almost identical to that of paper. The process takes longer for commercially available ACC. Furthermore, it was demonstrated that material recycling of ACC in the recycling paper loop was only feasible to a limited extent. The cellulose matrix between the fibres leads to a strong binding of the composite. This makes disintegration and fibre recovery difficult. Nevertheless, ACC represents a promising approach for packaging, particularly in regard to the global issue of littering.

The enzymatic breakdown of lignin generates a spectrum of aromatic monomers — including vanillin, guaiacol, syringaldehyde, vanillic acid, ferulic acid, and p-coumaric acid — that serve as platform chemicals for pharmaceuticals, fragrances, resins, and bio-based polymers. However, its complex and recalcitrant structure necessitates highly efficient enzymatic systems for depolymerization. This review systematically classifies ligninolytic enzymes into five functional categories: laccases, peroxidases (including manganese peroxidases, lignin peroxidases, and versatile peroxidases), cytochrome P450s, dye-decolorizing peroxidases (DyPs), and auxiliary enzymes, evaluating their distinct roles and synergies in lignin breakdown. Laccases emerge as particularly versatile biocatalysts due to their widespread occurrence, broad substrate specificity, and operational flexibility under diverse conditions. Peroxidases drive critical oxidative reactions, while DyPs represent a functionally robust peroxidase class with superior stability under extreme pH, temperature, and pressure. Complementary enzymes such as etherases and lignin-mimetic systems further expand the toolbox for lignin valorization. To overcome inherent limitations of native enzymes, protein engineering strategies were highlighted to enhance catalytic efficiency, stability, and substrate affinity. Additionally, enzyme immobilization on advanced matrices (e.g., metal-organic frameworks) is discussed as a breakthrough approach to improve reusability and reaction scalability. These integrated advancements pave the way for sustainable lignin valorization.

A composite sizing system was developed based on polyvinyl alcohol (PVOH) and the silane coupling agent KH550, with the innovative incorporation of root extract from Stellera chamaejasme L.—a characteristic raw material for traditional Tibetan paper. A novel bio-based surface sizing agent with integrated strength enhancement, water resistance, and natural antibacterial properties was successfully prepared. Investigation of KH550 dosage revealed that it acts as a “chemical bridge” between PVOH and paper fibers via a cross‑linking reaction, in which it condenses with hydroxyl groups on cellulose and PVOH to form covalent Si–O–C bonds. This enhanced interfacial bonding strength and film density, whereas excessive addition led to molecular aggregation. The optimal paper properties were obtained at a KH550 dosage of 1 g, with a sizing weight of 34.1%, tensile index of 50.1 N·m/g, sizing degree of 33 s (43.5% higher than that with PVOH alone), tear index of 219.5 mN·m²/g (163% higher than that of the unsized control), and water contact angle of 106°. Performance indicators were significantly improved compared with the control group without KH550. Notably, the Stellera chamaejasme root extract derived from traditional Tibetan papermaking raw materials effectively endows the paper coating with excellent antibacterial properties.

Using organic materials in fruit production is an effective way to reduce dependency on chemical fertilization. This can cause many problems for the soil, increase beneficial microbes, and improve fruit quality. Organic fertilization provides the necessary nutrients to fruit trees safely, without causing any undesirable effects on soil fertility. Therefore, this study was conducted to examine the effects of soil application of vermicompost (VC), either alone or combined with spraying melatonin (MT), on the vegetative growth, productivity, and nutritional status of mango cv. Keitt. Mango trees were fertilized in January 2024 and 2025 with VC at 0, 3, and 5 kg for tree, then sprayed three times starting mid-February with 0, 50, and 100 mg L⁻¹ MT at 20-day intervals compared to untreated trees. The treatments were arranged in a split-plot design within a randomized block design with five replicates. The results indicated that adding VC to the soil and spraying MT significantly enhanced the growth, productivity, and fruit quality of mango trees. The combined application of VC with MT spraying showed a notably greater increase than the individual treatments. The best results were achieved with 5 VC + 100 MT, followed by 5 VC + 50 mg L⁻¹ MT, outperforming other treatments across the two seasons.

Although the high flexibility of PBAT (polybutylene adipate-co-terephthalate) makes it ideal for food packaging, its poor antibacterial properties restrict its use in the food industry and shorten the shelf life of food products. In this work, PBAT polymer film was modified with bay leaf essential oil to improve its antibacterial properties. Gas chromatography-mass spectrometric analysis showed 38 chemical components in bay leaf. The main absorbances were the strong C=O stretching of the ester group (1720 to 1730 cm⁻¹) and the aliphatic C–H stretching (2950 and 2850 cm⁻¹). An increase in the amount of essential oil resulted in a decrease in the melting temperature of the PBAT, confirming a plasticizing effect. No antibacterial activity was observed in the PBAT films containing 5 wt% or 10 wt% bay leaf oil against either gram-positive or gram-negative bacteria. However, PBAT films containing 15 wt% and 20 wt% bay leaf oil exhibited zone diameters of 8 and 12 mm, respectively, against the E. coli strain. PBAT films with enhanced plasticizing and antibacterial properties, resulting from the addition of 20 wt% bay leaf oil, could be of great interest to the food packaging and biomedical industries.