Search Results (776)

Oak wood is a popular construction material in Europe. In the course of its service life, this wood is subject to structural changes resulting from the environmental conditions to which it is exposed, in addition to the effects of aging. Samples of naturally occurring historic European oak (Quercus robur L.) were obtained from foundation piles that were utilized to reinforce the riverbanks in Poland, the Vistula River basin, dating to the 2nd century, as well as from a 14th-century settlement on the river in Slupsk. Reference wood was also obtained from contemporary harvesting operations in the vicinity of Slupsk, Poland. The presence of structural changes resulting from partial wood degradation was confirmed through the utilization of FTIR spectroscopy analysis, SEM with BSD microscopy, and chromatic parameters. The differences in the color of historic and reference wood were significant (based on Kruskal–Wallis test = 46.38, where p < 0.001). The results of chemical analysis showed an increase in the proportion of lignin and a decrease in carbohydrate components for the old wood. A higher degree of change in lignin content was observed in historic wood (32–38%) compared to the fresh wood sample (25%). Our study showed that the collected data can be applied to the preparation database of heritage wood materials. Full article

Pollution from synthetic polymers, particularly low-density polyethylene (LDPE), poses a significant environmental challenge due to its chemical stability and resistance to degradation. This study investigates an eco-biotechnological approach involving bacterial strains isolated from insect guts—Bacillus cereus LDPE-DB2 (from Achroia grisella) and Pseudomonas aeruginosa LDPE-DB26 (from Coptotermes formosanus)—which demonstrate the ability to degrade LDPE, potentially through the action of lignin-modifying enzymes. These strains exhibited notable biofilm formation, enzymatic activity, and mechanical destabilization of LDPE. LDPE-DB2 exhibited higher LDPE degradation efficiency than LDPE-DB26, achieving a greater weight loss of 19.8% compared with 11.6% after 45 days. LDPE-DB2 also formed denser biofilms (maximum protein content: 68.3 ± 2.3 µg/cm²) compared with LDPE-DB26 (55.2 ± 3.1 µg/cm²), indicating stronger surface adhesion. Additionally, LDPE-DB2 reduced LDPE tensile strength (TS) by 58.3% (from 15.3 MPa to 6.4 ± 0.4 MPa), whereas LDPE-DB26 induced a 43.1% reduction (to 8.7 ± 0.23 MPa). Molecular weight analysis revealed that LDPE-DB2 caused a 14.8% decrease in weight-averaged molecular weight (Mw) and a 59.1% reduction in number-averaged molecular weight (Mn), compared with 5.8% and 32.7%, respectively, for LDPE-DB26. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and gel permeation chromatography (GPC) analyses revealed substantial polymer chain scission and crystallinity disruption. Gas chromatography–mass spectrometry (GC-MS) identified environmentally benign degradation products, including alkanes, alcohols, and carboxylic acids. This study demonstrates a sustainable route to polyethylene biotransformation using insect symbionts and provides insights for scalable, green plastic waste management strategies in line with circular economy goals. Full article

This study aimed to develop an effective method to overcome the challenge of straw return in cold-region soil. We systematically investigated the synergistic mechanism of montmorillonite (MMT) and composite amino acid (CAA) on straw humification and carbon sequestration through a low-temperature litterbag field experiment. The results indicate that the combined treatment (MMT-CAA) significantly increased the decomposition rate of straw by 42.1% compared to the control (CK), with MMT showing particular efficacy in lignin degradation (28.3% reduction), while the CAA preferentially decomposed cellulose (19.7% reduction). An FTIR analysis of the decomposition products confirmed these findings. Water-soluble organic carbon (WEOC) and its three-dimensional fluorescence spectra exhibited a 25.0% increase in MMT-CAA and enhanced aromaticity of humic acid-like substances. Humic substances and their ¹³C-NMR revealed that MMT-CAA enhanced humic acid formation and molecular stability by 31.4% (with a 47.8% increase in aromaticity). A further redundancy analysis and symbiotic network of microorganisms demonstrated that MMT-CAA increased the abundance of lignocellulose-degrading phyla (Actinomycetes and Stramenomycetes) and the formation of a complex co-degradation network. Field corn planting trials indicated that MMT-CAA increased plant height by 55.1%, stem thickness by 58.7%, leaf area by 70.2%, and the SPAD value by 41.1%. Additionally, MMT significantly reduced CO₂ and N₂O emission fluxes by 35.6% and 15.8%, respectively, while MMT-CAA increased CH₄ uptake fluxes by 13.4%. This study presents an innovative strategy, providing mechanistic insights and practical solutions to synergistically address the challenges of slow straw decomposition and carbon loss in cold regions. Full article

This study innovatively integrates ball-milled manganese dioxide nanozyme (MDMP) with the Streptomyces rochei ZY-2 inoculant in aerobic rice straw composting. The ZY-2 inoculant efficiently degrades the three major components to generate humus precursors such as phenols and quinones, while the MnO₂ nanozyme accelerates precursor polymerization into stable humic acid (HA) via oxygen vacancy-mediated catalytic activity. Simultaneously, this combination regulates microbial communities to reduce greenhouse gas emissions. The results show that the co-treatment group (ZY-2+ MnO₂ nanozyme) had an increased HA content by 30.8%, raised HA/FA ratio by 31.6%, and degradation rates of 30.75%, 31.39%, and 16.74% for cellulose, hemicellulose, and lignin, respectively. Additionally, cumulative emissions of CH₄, N₂O, and NH₃ were significantly reduced by 35.22%, 28.23%, and 25.67% compared to the control, attributed to the MnO₂ nanozyme’s inhibition of methanogens, enhanced nitrogen fixation, and ZY-2-driven microbial metabolic optimization. This study proposes a dual-effect strategy of “enhanced humification-synergistic greenhouse gas mitigation” for agricultural waste recycling, demonstrating significant practical value. Full article

Repeated freeze-thaw cycles in seasonally frozen regions significantly degrade the mechanical properties of clay, posing serious challenges to geotechnical infrastructure stability. This study investigates the compressibility behavior of lignin fiber-reinforced clay under freeze-thaw conditions through one-dimensional consolidation tests and microstructural analysis. Clay specimens containing 0.0%, 0.5%, 1.0%, 1.5%, and 2.0% lignin fibers by mass were subjected to 0, 1, 4, and 10 freeze-thaw cycles to simulate typical seasonal variations. The results indicate that reinforcement with lignin fibers markedly enhances the soil’s resistance to freeze-thaw-induced degradation. Specifically, in unreinforced clay, 10 freeze-thaw cycles reduced the pre-consolidation pressure from 139 kPa to 97 kPa. With 2.0% lignin fiber, the pressure increased to 186 kPa under unfrozen conditions and remained at 120 kPa after 10 cycles. SEM and MIP analyses revealed that lignin fibers form interconnected networks that inhibit the formation and expansion of strip pores and constrained pore coarsening caused by freeze-thaw action, effectively stabilizing the soil structure. A model incorporating both fiber content and freeze-thaw cycle effects was proposed to predict compression behavior, and the model accurately captured the experimental compression curves across all test conditions. This study provides a theoretical and experimental basis for the application of natural fiber-reinforced clay in cold-region geotechnical engineering, offering a sustainable and effective alternative to traditional stabilization methods. Full article

The increasing frequency of wildfires in larch forests across the discontinuous permafrost zone of Eastern Eurasia heightens the vulnerability of soil organic matter (SOM) under a warming climate. However, post-fire SOM thermal stability in this frequently burned forest region remain poorly understood. We assessed the long-term effects of wildfire on SOM structure and thermal stability in burned and unburned larch forests using complex analytical approaches: pyrolysis–gas chromatography/mass spectrometry (TMAH-py-GC/MS) and thermogravimetry/differential thermal analysis (TG/DTA). The focus was on the upper mineral soil horizon, where fire impacts may persist for decades. Sixteen years post-fire, total carbon content did not differ significantly between burned and control soils. Nonetheless, the molecular composition and thermal properties of SOM showed marked post-fire alterations. Burned soils exhibited higher proportions of lignin-derived compounds and reduced levels of short-chain fatty acid methyl esters. A lower degradation temperature (T50) and a higher thermal mass loss of labile fractions indicate a decrease in the thermal stability of SOM after fire. Our study shows that recurrent forest fires in larch forests of the Russian Far East decrease the thermal stability of soil organic matter, thereby increasing its vulnerability to subsequent fire degradation. Full article

Pythium schmitthenneri, a soilborne pathogen responsible for root rot in olive trees, poses a significant threat to olive production. Managing this pathogen remains challenging due to its aggressive root colonization and the limited efficacy of conventional control methods. Given the concerns associated with chemical treatments, this study evaluated the resistance of eight olive varieties to P. schmitthenneri-induced root rot under controlled greenhouse conditions by assessing structural and biochemical defense mechanisms. Greenhouse trials revealed that Arbequina, Koroneiki, and Haouziya exhibited strong resistance, with 0% disease severity, while Picholine Marocaine and Picholine Languedoc were highly susceptible, reaching 100% disease severity. Growth parameters varied significantly, with susceptible varieties showing severe reductions in root length (RL), root fresh weight (RFW), and root dry weight (RDW), whereas resistant varieties maintained these parameters unchanged. While shoot length (SL) remained unaffected across all varieties, shoot fresh weight (SFW) and shoot dry weight (SDW) were significantly reduced in susceptible ones. Fourier-transform infrared (FTIR) spectroscopy revealed that resistant varieties maintained stable levels of lignin, cellulose, and polysaccharides, while susceptible ones exhibited extensive cell wall degradation. Additionally, total polyphenol content (TPC) and total flavonoid content (TFC) significantly increased in resistant varieties upon infection, whereas susceptible varieties experienced a substantial decline. These findings highlight the crucial role of structural and biochemical defenses in olive resistance to P. schmitthenneri and suggest that selecting resistant varieties could serve as a sustainable strategy for managing root rot in olive production. Full article

Fungal lytic polysaccharide monooxygenases (LPMOs) have revolutionized the field of biomass degradation by introducing an oxidative mechanism that complements traditional hydrolytic enzymes. These copper-dependent enzymes catalyze the cleavage of glycosidic bonds in recalcitrant polysaccharides such as cellulose, hemicellulose, and chitin, through the activation of molecular oxygen (O₂) or hydrogen peroxide (H₂O₂). Their catalytic versatility is intricately modulated by structural features, including the histidine brace active site, surface-binding loops, and, in some cases, appended carbohydrate-binding modules (CBMs). The oxidation pattern, whether at the C1, C4, or both positions, is dictated by subtle variations in loop architecture, amino acid microenvironments, and substrate interactions. LPMOs are embedded in a highly synergistic fungal enzymatic system, working alongside cellulases, hemicellulases, lignin-modifying enzymes, and oxidoreductases to enable efficient lignocellulose decomposition. Industrial applications of fungal LPMOs are rapidly expanding, with key roles in second-generation biofuels, biorefineries, textile processing, food and feed industries, and the development of sustainable biomaterials. Recent advances in genome mining, protein engineering, and heterologous expression are accelerating the discovery of novel LPMOs with improved functionalities. Understanding the balance between O₂- and H₂O₂-driven mechanisms remains critical for optimizing their catalytic efficiency while mitigating oxidative inactivation. As the demand for sustainable biotechnological solutions grows, this narrative review highlights how fungal LPMOs function as indispensable biocatalysts for the future of the Circular Bioeconomy and green industrial processes. Full article

The development of sustainable and functional nanocomposites has attracted considerable attention in recent years due to their broad spectrum of potential applications, including wood preservation. Also, a global goal is to reuse the large volumes of waste for environmental issues. In this context, the aim of the study was to obtain soda lignin particles, to graft ZnO nanoparticles onto their surface and to apply these hybrids, embedded into a biodegradable polymer matrix, as protection/preservation coating for oak wood. The organic–inorganic hybrids were characterized in terms of compositional, structural, thermal, and morphological properties that confirm the efficacy of soda lignin extraction and ZnO grafting by physical adsorption onto the decorating support and by weak interactions and coordination bonding between the components. The developed solution based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and lignin-ZnO was applied to oak wood specimens by brushing, and the improvement in hydrophobicity (evaluated by water absorption that decreased by 48.8% more than wood, humidity tests where the treated sample had a humidity of 4.734% in comparison with 34.911% for control, and contact angle of 97.8° vs. 80.5° for untreated wood) and UV and fungal attack protection, while maintaining the color and aspect of specimens, was sustained. L.ZnO are well dispersed into the polymer matrix, ensuring a smooth and less porous wood surface. According to the results, the obtained wood coating using both a biodegradable polymeric matrix and a waste-based preservative can be applied for protection against weathering degradation factors, with limited water uptake and swelling of the wood, UV shielding, reduced wood discoloration and photo-degradation, effective protection against fungi, and esthetic quality. Full article

Olive tree branches (OB) and leaves (OL) from the Viseu region (Portugal) were studied for their chemical composition and liquefaction behavior using polyalcohols. Chemical analysis revealed that OL contained higher ash content (4.08%) and extractives, indicating more bioactive compounds, while OB had greater α-cellulose (30.47%) and hemicellulose (27.88%). Lignin content was higher in OL (21.64%) than OB (16.40%). Liquefaction experiments showed that increasing the temperature from 140 °C to 180 °C improved conversion, with OB showing a larger increase (52.5% to 80.9%) compared to OL (66% to 72%). OB reached peak conversion faster, and the optimal particle size for OB was 40–60 mesh, while OL performed better at finer sizes. OL benefited more from higher solvent ratios, whereas OB achieved high conversion with less solvent. FTIR analysis confirmed that acid-catalyzed liquefaction breaks down lignocellulosic structures, depolymerizes cellulose and hemicellulose, and modifies lignin, forming hydroxyl, aliphatic, and carbonyl groups. These changes reflect progressive biomass degradation and the incorporation of polyalcohol components, converting solid biomass into a reactive, polyol-rich liquid. The study highlights the distinct chemical and processing characteristics of olive branches and leaves, informing their potential industrial applications. Full article

Anaerobic digestion (AD) is a sustainable method of treating organic waste to generate methane-rich biogas. However, the complex lignocellulosic nature of organic waste in most cases limits its biodegradability and methane potential. This review evaluates pretreatment technology to optimize AD performance, particularly in developing countries like Ghana, where organic waste remains underutilized. A narrative synthesis of the literature between 2010 and 2024 was conducted through ScienceDirect and Scopus, categorizing pretreatment types as mechanical, thermal, chemical, biological, enzymatic, and hybrid. A bibliometric examination using VOSviewer also demonstrated global trends in research and co-authorship networks. Mechanical and thermal pretreatments increased biogas production by rendering the substrate more available, while chemical treatment degraded lignin and hemicellulose, sometimes more than 100% in methane yield. Biological and enzymatic pretreatments were energy-consuming and effective, with certain enzymatic blends achieving 485% methane yield increases. The study highlights the synergistic benefits of hybrid approaches and growing global interest, as revealed by bibliometric analysis; hence, the need to explore their potential in Ghana. In Ghana, this study concludes that low-cost, biologically driven pretreatments are practical pathways for advancing anaerobic digestion systems toward sustainable waste management and energy goals, despite infrastructure and policy challenges. Full article

This article presents a review of several non-exclusive pathways for the sequestration of soil organic carbon, which can be classified into two large classical groups: the modification of plant and microbial macromolecules and the abiotic and microbial neoformation of humic substances. Classical studies have established a causal relationship between aromatic structures and the stability of soil humus (traditional hypotheses regarding lignin and aromatic microbial metabolites as primary precursors for soil organic matter). However, further evidence has emerged that underscores the significance of humification mechanisms based solely on aliphatics. The precursors may be carbohydrates, which may be transformed by the effects of fire or catalytic dehydration reactions in soil. Furthermore, humic-type structures may be formed through the condensation of unsaturated fatty acids or the alteration of aliphatic biomacromolecules, such as cutins, suberins, and non-hydrolysable plant polyesters. In addition to the intrinsic value of understanding the potential for carbon sequestration in diverse soil types, biogeochemical models of the carbon cycle necessitate the assessment of the total quantity, nature, provenance, and resilience of the sequestered organic matter. This emphasises the necessity of applying specific techniques to gain insights into their molecular structures. The application of appropriate analytical techniques to soil organic matter, including sequential chemolysis or thermal degradation combined with isotopic analysis and high-resolution mass spectrometry, derivative spectroscopy (visible and infrared), or ¹³C magnetic resonance after selective degradation, enables the simultaneous assessment of the concurrent biophysicochemical stabilisation mechanisms of C in soils. Full article

Aromatic compounds are vital in both natural and synthetic chemistry, and they are traditionally sourced from non-renewable petrochemicals. However, plant biomass, particularly lignin, offers a renewable alternative source of aromatic compounds. Lignin, a complex polymer found in plant cell walls, is the largest renewable source of aromatic compounds, though its degradation remains challenging. Lignin can be chemically degraded through oxidation, acid hydrolysis or solvolysis. As an alternative, microorganisms, including fungi, could offer a sustainable alternative for breaking down lignin. The aromatic compounds released from lignin, by either microbial, chemical or enzymatic degradation, can be used by microorganisms to produce valuable compounds. Fungi possess unique enzymes capable of converting aromatic compounds derived from lignin or other sources into chemical building blocks that can be used in several industries. However, their aromatic metabolic pathways are poorly studied compared to bacterial systems. In the past, only a handful of genes and enzymes involved in the aromatic metabolic pathways had been identified. Recent advances in genomics, proteomics, and metabolic engineering are helping to reveal these metabolic pathways and identify the involved genes. This review highlights recent progress in understanding fungal aromatic metabolism, focusing on how Aspergillus niger converts plant-derived aromatic compounds into potentially useful products and the versatility of aromatic metabolism within the Aspergillus genus. Addressing the current knowledge gaps in terms of fungal pathways could unlock their potential for use in sustainable technologies, promoting eco-friendly production of chemical building blocks from renewable resources or bioremediation. Full article

Biodegradation is a green and efficient method for lignin depolymerization and conversion. In order to screen potential bacterial strains for efficient lignin degradation, composts of cow dung and wheat straw were prepared, and the dynamic changes in the predicted bacterial community structure and function in different periods of the composts were investigated. Then, bacteria with an efficient lignin degradation ability were finally screened out from the compost samples. Based on the monitoring results of the physicochemical indexes of the composting process, it was found that the temperature and pH of the compost firstly increased and then decreased with the extension of time, and the water content and C/N gradually decreased. High-throughput sequencing of compost samples from the initial (DA), high-temperature (DB), and cooling (DC) periods revealed that the number of OTUs increased sharply then stabilized around 2000, and the alpha diversity of the bacterial community decreased firstly and then increased. The predominant phyla identified included Proteobacteria, Firmicutes, Chloroflexi, and Bacteroidetes, determined by the relative abundance of beta-diversity-associated species. Functional gene analysis conducted using Tax4Fun revealed that the genes were primarily categorized into Metabolism, Genetic Information Processing, Environmental Information Processing, and Cellular Processes. Based on the decolorization of aniline blue and the degradation efficiency of alkali lignin, eight bacterial strains were isolated from compost samples at the three stages. Cupriavidus sp. F1 showed the highest degradation of alkali lignin with 66.01%. Cupriavidus sp. D8 showed the highest lignin degradation potential with all three enzyme activities significantly higher than the other strains. The results provide a strategy for the lignin degradation and utilization of biomass resources. Full article

Against the backdrop of the green circular economy, the exploration of reliable and sustainable applications of lignocellulosic biomass (LCBM) has emerged as a critical research frontier. The utilization of LCBM as a ruminant roughage source offers a promising strategy to address two pressing issues: the “human-animal competition for food” dilemma and the environmental degradation resulting from improper LCBM disposal. However, the high degree of lignification in LCBM significantly restricts its utilization efficiency in ruminant diets. In recent years, microbial pretreatment has gained considerable attention as a viable approach to reduce lignification prior to LCBM application as ruminant feed. White-rot fungi (WRF) have emerged as particularly noteworthy among various microbial agents due to their environmentally benign characteristics and unique lignin degradation selectivity. WRF demonstrates remarkable efficacy in enzymatically breaking down the rigid lignocellulosic matrix (comprising lignin, cellulose, and hemicellulose) within LCBM cell walls, thereby reducing lignin content—a largely indigestible component for ruminants—while simultaneously enhancing the nutritional profile through increased protein availability and improved digestibility. Solid-state fermentation mediated by WRF enhances LCBM utilization rates and optimizes its nutritional value for ruminant consumption, thereby contributing to the advancement of sustainable livestock production, agroforestry systems, and global environmental conservation efforts. This review systematically examines recent technological advancements in WRF-mediated solid-state fermentation of LCBM, evaluates its outcomes of nutritional enhancement and animal utilization efficiency, and critically assesses current limitations and future prospects of this innovative approach within the framework of circular bioeconomy principles. Full article