Search Results (82)

Chile is among the leading global exporters of pulp and paper, supported by extensive plantations of Pinus radiata and Eucalyptus spp. This review synthesizes recent progress in the valorization of forestry biomass in Chile, including both established practices and emerging bio-based applications. It highlights advances in lignin utilization, nanocellulose production, hemicellulose processing, and tannin extraction, as well as developments in thermochemical conversion technologies, including torrefaction, pyrolysis, and gasification. Special attention is given to non-timber forest products and essential oils due to their potential bioactivity. Sustainability perspectives, including Life Cycle Assessments, national policy instruments such as the Circular Economy Roadmap and Extended Producer Responsibility (REP) Law, are integrated to provide context. Barriers to technology transfer and industrial implementation are also discussed. This work contributes to understanding how forestry biomass can support Chile’s transition toward a circular bioeconomy. Full article

Biomass liquefaction is a promising thermochemical route to convert lignocellulosic residues into bio-oil. This study evaluates the liquefaction behavior of 13 biomasses with varying particle sizes (0.3–2.0 mm) and moisture contents (5–11%) under mild solvolysis conditions. High-performance liquid chromatography (HPLC-RID) and thermogravimetric analysis (TGA) were used to characterize bio-oil composition and biomass properties, respectively. Maximum conversion (72%) was achieved for Miscanthus, while Ulva lactuca reached only 23% due to its low carbohydrate content. Hemicellulose-rich feedstocks showed higher yields, whereas high lignin content generally reduced conversion. Furfural was the main compound identified in the aqueous phase (up to 51 g/L), reflecting extensive pentose degradation. Laboratory and industrial-scale liquefaction of cork and eucalyptus revealed scale-dependent differences. Industrial cork bio-oil showed increased xylose (0.70 g/L) and furfural (0.40 g/L), while industrial eucalyptus exhibited elevated levels of acetic (0.46 g/L) and formic acids (0.71 g/L), indicating enhanced deacetylation and demethoxylation reactions. These findings offer valuable insights for optimizing feedstock selection and process conditions in biomass liquefaction. The valorization of lignocellulosic residues into bio-oil contributes to the development of scalable, low-carbon technologies aligned with circular economy principles and bio-based industrial strategies. Full article

Lignin, one of the most abundant biopolymers on Earth, holds significant promise as a feedstock for applications such as resins, biofuels, foams, and carbon fibres. However, despite extensive research, lignin remains largely underutilised, with its primary use limited to combustion for energy. While lignin’s structural features are well documented, there is a lack of consistent data on its key physical properties such as density. This study addresses that gap by providing experimentally determined values for skeletal and bulk densities of lignins obtained through different extraction methods, including Kraft; soda pulping; and particularly the ionoSolv process, using ionic liquids such as N,N-dimethyl butyl ammonium hydrogen sulphate ([DMBA][HSO₄]). The results reveal correlations between lignin chemical structure and density in ionoSolv-extracted lignins from Eucalyptus Red Grandis, suggesting opportunities to tune the extraction parameters for targeted material properties. The skeletal density of the lignin samples ranged from 1.3370 to 1.4598 g/cm³, while the bulk density varied more widely—from 0.0944 to 0.5302 g/cm³—reflecting significant differences in particle packing and porosity depending on the biomass source and extraction method. These findings contribute valuable data for process design and scale-up, advancing the commercial viability of lignin-based products. Full article

Alkaline treatment is well suited for extracting high-molecular-weight hemicelluloses, specifically hardwoods xylans, which, due to their polymer structure and chemical characteristics, enable the production of films with desirable mechanical, barrier, and optical properties for packaging applications. Despite its relevance, the optimization of antisolvent addition has received little attention in the literature. This study explores the use of eucalyptus industrial residue as feedstock, utilizing a statistical design to determine the optimal extraction conditions for hemicelluloses while minimizing the lignin content in the recovered liquor. The process uses alkali loads that are compatible with those in conventional Kraft pulp mills. Optimal extraction conditions involve a temperature of 105 °C, 16.7% NaOH charge, and 45 min at maximum temperature. The resulting liquor was subjected to ethanol precipitation under varying pH conditions (initial pH, 9, 7, 5, and 2) and different ethanol-to-liquor ratios (1:1 to 4:1). The acidification was performed using hydrochloric, sulfuric, and acetic acids. Ethanol served as the main antisolvent, while isopropyl alcohol and dioxane were tested for comparison. Results show that 2.3 ± 0.2% of xylans (based on oven-dry biomass) could be extracted, minimizing lignin content in the liquor. This value corresponds to the extraction of 15.6% of the xylans present in the raw material. The highest xylan precipitation yield (78%) was obtained at pH 7, using hydrochloric acid for pH adjustment and an ethanol-to-liquor ratio of 1:1. These findings provide valuable insight into optimizing hemicellulose recovery through antisolvent precipitation, contributing to more efficient biomass valorization strategies within lignocellulosic biorefineries. Full article

The rapid growth of the global population has led to significant environmental impacts, driven by the unsustainable extraction of resources and waste generation. To address these challenges, the valorisation of by-products from different industries is crucial for maximising resource efficiency, reducing waste, and promoting sustainable practices. In this study, a comprehensive characterisation of the physicochemical properties of plant-based by-products, including rice husk (RH), oregano stalks (OS), eucalyptus leaves (EL), and almond shells (AS), was conducted. The analyses of the residues showed that, despite the similarities regarding cellulose and lignin content in all materials, RH and OS present a higher cellulose content, while EL and AS contain a greater percentage of oils. Additionally, calcium and potassium were identified as the metals at higher concentrations in all residues. The EL and RH present significant hydrophobic properties compared to the other analysed residues, showcased by their lower wettability. The morphological analyses of the waste residues revealed that OS and RH particles exhibit fibrous characteristics with heterogeneous sizes, while EL is a blend of fibrous and amorphous particles, and AS is composed of smaller particles with irregular shapes. All the residues retained their antioxidant properties over a 12-month storage period, with no degradation due to grinding. The composition and physicochemical properties of these residues highlight their potential to be used in distinct industries, including construction, transport, and textiles, promoting a circular economy and supporting a more sustainable environment. Full article

Herein, the clustered regularly interspaced short palindromic repeats (CRISPRs)/CRISPRs-associated protein 9 (Cas9) technology for genome editing was used to develop an efficient gene editing system for Eucalyptus urophylla × Eucalyptus grandis and generate a new Eucalyptus germplasm with reduced lignin content in the pulp for environmental sustainability in papermaking. By targeting the cinnamate-4-hydroxylase (C4H) gene in E. urophylla × E. grandis, the recombinant plasmid pHEE401E-35S-RUBY-EuC4H was constructed through homologous recombination. This plasmid was then transformed into E. urophylla × E. grandis callus tissue. Using the RUBY gene as a marker, positive transformants were screened based on the callus tissue phenotype. Subsequent PCR and sequencing confirmed the successful creation of mutants with a significantly edited EuC4H gene. This method offers a valuable framework and guidance for genetically improving and establishing an efficient gene editing system in Eucalyptus. Full article

Bio-oil energy use in agricultural systems provides sustainable solutions for powering machinery operations and heating and cooling environments in facilities. However, its potential in South Africa is constrained by the limited availability of energy substrate that does not compromise food production, land use, and water resources. This study investigated the physical and chemical properties of six invasive alien plant species (IAPs), three woody species (Acacia mearnsii, Eucalyptus grandis, and Pinus patula), and three nonwoody species (Lantana camara, Chromolaena odorata, and Solanum mauritianum) to assess their suitability for bio-oil production. Key analyses included structural, elemental, proximate, atomic ratio, higher heating value (HHV), and thermogravimetric analysis (TGA) analyses. The results showed that woody IAPs had a significantly higher structural composition (p < 0.05), improving bio-oil yield. The bio-oil can be blended with diesel for agricultural use, while lignin-derived biochar serves as a soil amendment. Higher carbon and hydrogen contents enhanced HHV and combustion, while lower nitrogen and sulfur levels reduced emissions. Despite oxygen hindering pyrolysis, its bioactive properties support crop protection. Compared to South African coal, IAP-derived bio-oil shares similarities with peat coal and could be used for greenhouse heating. This study promotes energy efficiency in agriculture, reduces fossil fuel dependence, and supports environmental sustainability by repurposing IAPs. Additional studies should focus on lignin pretreatment and bio-oil upgrading to reduce oxygenated compounds. Full article

The current widespread use of plastics is a significant source of environmental pollution and increases the carbon load in the atmosphere, which has precipitated an urgent drive to replace plastics with biomass-based materials. In this paper, we prepared a lignocellulose-based, high-strength, water-resistant composite based on eucalyptus waste sawdust combined with a polyurethane prepolymer. The preparation process included pretreating sawdust with deep eutectic solvents (DESs) to remove some of the lignin and hemicellulose. A prepolymer preparation involving isocyanate groups using the prepolymerization of polyethylene glycol (PEG) with hexamethylene diisocyanate (HDI) grafted the prepolymers to the hydroxyl of the pretreated wood fibers, which were subsequently blended with acetylated pretreated sawdust to create the composite. The composite contained 67% wood fibers, possessed good tensile strength, and exhibited Young’s moduli of 18 MPa and 484 MPa. It was water-resistant with a contact angle of 92° and had a low water absorption of 32%, and it maintained a wet tensile strength of 5.71 MPa. The composite offers several advantages, including UV protection and thermal stability. This high-performance wood waste composite provides an alternative green production option for producing plastic materials. Full article

This study investigated the bonding strength and chemical composition (as an influencing factor of adhesion) of red eucalyptus (Eucalyptus camaldulensis) (EUW) and grey poplar (Populus canescens) (GPOW) wood surfaces, comparing their suitability for indoor and outdoor wood-building applications. The research focused on adhesion strength using different coatings and adhesives, including lasure and 2K lacquer. The results showed that whilst both wood species had a conveniently high cellulose content, GPOW had a higher cellulose content (48.21%) than EUW (45.18%). However, EUW demonstrated superiority in tensile shear strength tests when using structural adhesives. Additionally, EUW exhibited stronger pull-off adhesion with 2K lacquer (5.25 MPa) compared with GPOW (3.42 MPa), suggesting that whilst both reached the expectations, EUW was more appropriate for high-stress indoor applications like flooring or wall cladding. EUW and GPOW performed well with lasure, achieving comparable adhesion strengths. EUW had a density of 1020 kg/m³ vs. 575 kg/m³ for GPOW and stronger bonding capabilities than GPOW, which suggests that it is equally suitable for wood applications inside and outside buildings. The study concluded that whilst both wood species met expectations and proved to be suitable for doors, windows, and other wood-building product applications, GPOW was suitable for the production of cellulose-based products, while EUW was worth relying on for its excellent adhesion to coatings and adhesives. Full article

This study examines the effect of surfactant-enhanced enzymatic hydrolysis on eucalyptus Kraft pulps produced under high (CPHA) and mild (CPMA) alkali conditions to optimize saccharification and sugar yield. Compositional analysis revealed an increase in glucan content, from 40% in untreated eucalyptus to 70.1% in CPHA. Both pulps were hydrolyzed using Cellic^® CTec3 HS enzyme (Novozymes). A 2² factorial design revealed maximum sugar conversion (~100%) with enzyme loading of 10 FPU/g carbohydrate and 10% (w/v) solids. Tween 20 significantly boosted hydrolysis in CPMA, increasing reducing sugars from 42 g/L to 65 g/L and efficiency from 59.6% to 92.2% within 6 h. By contrast, Tween 80 and PEG 400 showed limited effects on CPMA. Surfactants mitigated lignin–enzyme interactions, especially in CPMA, as higher lignin content restricted hydrolysis efficiency. Phenolic content in the hydrolysates revealed that Tween 80 increased the release of inhibitory compounds, while Tween 20 kept phenolic levels lower. Overall, Tween 20 improved sugar yields and hydrolysis efficiency even with moderate lignin removal during kraft pretreatment, highlighting its potential to reduce enzyme loading and costs in industrial biorefineries. This study underscores the importance of optimizing surfactant selection based on biomass composition for effective enzymatic hydrolysis for cellulosic sugar recovery. Full article

This study investigates the sustainable use of Eucalyptus spp. bark through different chemical (hydrothermal, acid, alkaline, and bleaching) and physical (milling) pretreatments in the production of sustainable films. Valorization of agro-industrial residues and the demand for sustainable materials pose challenges for environmentally responsible solutions. Eucalyptus spp. bark, rich in cellulose, hemicellulose, and lignin, is a promising source for creating sustainable materials like films. In this study, the use of chemical and physical treatments aims to optimize biomass extraction and improve the chemical, thermal, mechanical, and optical properties of the films. The films showed an excellent light barrier capacity, with a transmittance below 1%. Crystallinity indices varied with the pretreatment: 8.15% for hydrothermal, 7.01% for alkaline, 7.63% for acid, and 10.80% for bleaching. The highest crystallinity value was obtained through bleaching, by removing amorphous components like lignin and hemicellulose. The alkaline pretreatment yielded stronger films (maximum stress of 8.8 MPa, Young’s modulus of 331.3 MPa) owing to the retained lignin and the hemicellulose reinforcing the material. This study contributes to the field of sustainable development by converting residues into valuable materials and by advancing the circular economy. The films’ specific properties make them suitable for applications like sustainable packaging, addressing environmental and industrial challenges. Full article

Lignin, the most abundant renewable aromatic polymer, has been shown to suppress the growth of mammalian tumor cells. Despite extensive studies on lignin structure and its engineering, there is little information on the biological activity of lignin in relation to its molecular structure or the molecular mechanisms by which lignin suppresses tumor cells in mammalian species. Here, we prepared microwave-assisted acid-catalyzed solvolysis lignin (MASL) from Japanese cedar and Eucalyptus globulus and assessed its effects on human and mouse tumor cells. SEC indicated that MASL consists of oligomeric aromatics from the woody plants. Our data showed that MASL significantly reduced the viability of tumor cells by modulating apoptotic pathways. MASL treatment upregulated TNF-α, Fas, and FasL expression levels, while suppressing anti-apoptotic NF-κB and mTOR pathways in tumor cells. In vivo experiments were also performed using tumor-bearing mice to confirm the anti-tumor effects of MASL. Repetitive administrations of a MASL (YM CL1T) significantly inhibited tumor growth in mice in association with elevation of caspase 3 expression. These findings strongly suggest the potential usefulness of low-molecular-weight lignin as an effective therapeutic against malignancies. Full article

Understanding decomposition patterns of mixed-leaf litter from agroforestry species is crucial, as leaf litter in ecosystems naturally occurs as mixtures rather than as separate individual species. We hypothesized that litter mixtures with larger trait divergence would lead to faster mass loss and more balanced nutrient release compared to single-species litter. Specifically, we expected mixtures containing nutrient-rich species to exhibit synergistic effects, resulting in faster decay rates and sustained nutrient release, while mixtures with nutrient-poor species would demonstrate antagonistic effects, slowing decomposition. We conducted a mesocosm experiment using a custom wooden setup filled with soil, and the litterbag method was used to test various leaf litter mixtures. The study involved leaf litter from six agroforestry tree species: three species from humid highland regions and three from semi-arid regions. Treatments included three single-species leaf litter mixtures, three two-species mixtures, and one three-species mixture, based on the sampling region. Species included Calliandra calothyrsus (Ca), Croton megalocarpus (Cr), Grevillea robusta (G), Alnus acuminata (A), Markhamia lutea (M), and Eucalyptus globulus (E). Decay rate constants (k) were estimated using non-linear least-squares regression and observed mass loss was compared to predicted values for mixed-species litter treatments to assess synergistic and antagonistic effects. A two-way linear mixed-effects model was employed to explain variation in mass loss. Results indicate positive non-additive effects for leaf litter mixtures including nutrient-rich species and negative non-additive effects for mixtures including nutrient-poor species. The mixture of Ca + Cr + G had positive non-additive or synergistic effects as it decomposed faster than its corresponding single-species litter. Leaf litters with higher lignin content, such as A + M + E and Ca + Cr + G, exhibited less lignin release compared to what would be expected based on individual litter types, demonstrating antagonistic effects. These findings highlight that both litter nutrient constituents and litter diversity play an important role in decomposition processes and therefore in the restoration of the degraded and nutrient-depleted soils of Rwanda. Full article

The forest industry produces several low-value by-products, such as bark, sawdust, limbs, and leaves, that are not ultimately disposed of and remain in the forests and sawmill facilities. Among these by-products are leaves, which contain not only cellulose fibers and lignin but also essential oils such as terpenes. These are biosynthesized in a similar way as cis-1,4-polyisoprene. In this context, this work evaluates the use of screened and unscreened dried Eucalyptus nitens leaves in natural rubber. Among the most relevant results of this work is a significant increase in mechanical properties, such as tensile strength and elongation at break, reaching values of 9.45 MPa and 649% of tensile strength and elongation at break, respectively, for a sample of natural rubber containing sieved dried leaves of Eucalyptus nitens. In addition, it is observed that the content of this vegetable filler allows for inhibiting the antibacterial effect of vulcanized rubber against several bacteria, such as Bacillus subtilis, Staphylococcus aureus, Escherichia coli K 12, Escherichia coli FT 17 and Pseudomonas fluorescens. These results are promising because they not only add value to a by-product of the forestry industry, improving the mechanical properties of natural rubber from a sustainable approach but also increase the affinity of rubber with bacterial microorganisms that may play a role in certain ecosystems. Full article

The conversion of biomass into bio-oil through the pyrolysis process offers numerous benefits, such as bio-fuel and bio-resin synthesis. However, for bio-oil usage for any application, understanding its composition is vital. Therefore, this study investigated the effects of different commonly available woody biomass (Douglas fir, eucalyptus, and poplar) on bio-oil composition. The bio-oil was produced through fast pyrolysis at 500 °C in a fluidized bed reactor and collected using an electrostatic precipitator. The chemical composition was analyzed using gas chromatography–mass spectroscopy, and the hydroxyl groups were quantified using phosphorous-31 nuclear magnetic resonance. The poplar bio-oil had the most significant proportion (67 area%) of lignin-derived compounds and the highest OH concentration (6 mmol g⁻¹). However, the proportion of carbohydrate-derived compounds was the largest (44 area %) in bio-oil produced from Douglas fir. Based on the OH concentration, poplar would be the most suitable feedstock for resin synthesis among the three feedstocks tested. Full article