Search Results (105)

Lignocellulosic residues represent a promising source of raw material for obtaining several high-value bioproducts, including cellulose and derivatives. One of the main barriers to cellulose extraction from these residues is the presence of other components associated with the cellulose matrix, such as lignin and hemicellulose. To overcome this limitation, it is necessary to apply specific treatments to remove these constituents. In this study, the effectiveness of three chemical treatment methods in the purification of cellulose extracted from urban pruning biomass of the species Clitoria fairchildiana were evaluated, namely (i) alkaline treatment using dilute sodium hydroxide solution; (ii) alkaline treatment followed by bleaching with hydrogen peroxide; and (iii) alkaline treatment followed by bleaching with hydrogen peroxide and sodium hydroxide combined. The changes in chemical composition and thermal properties caused by each method were analyzed using techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results demonstrated that the biomass pretreatment reduced the content of impurities, lignin, and hemicellulose, increasing the cellulose content to 37.16% in the combined treatment (H₂O₂ + NaOH). Furthermore, the FTIR spectra revealed characteristic bands of important functional groups, which reaffirmed the chemical structure of the extracted cellulose through the identification of hydroxyl, carbonyl groups, and C-H bending vibrations. Additionally, the SEM results indicated an increase in specific surface area and greater exposure of fibrils, providing visual confirmation of the removal of constituents from the cellulosic matrix. Collectively, these results demonstrate the potential of combined chemical treatments for the valorization of Clitoria fairchildiana biomass and indicate its technical feasibility for obtaining cellulose with a higher degree of purity. Full article

This study presents a thermodynamic equilibrium analysis of hydrogen-rich syngas production via biomass–methane co-pyrolysis, employing the Gibbs free energy minimization method. A critical temperature threshold at 700 °C is identified, below which methanation and carbon deposition are thermodynamically favored, and above which cracking and reforming reactions dominate, enabling high-purity syngas generation. Methane addition shifts the reaction pathway towards increased reduction, significantly enhancing carbon and H₂ yields while limiting CO and CO₂ emissions. At 1200 °C and a 1:1 methane-to-biomass ratio, cellulose produces 50.84 mol C/kg, 119.69 mol H₂/kg, and 30.65 mol CO/kg; lignin yields 78.16 mol C/kg, 117.69 mol H₂/kg, and 19.14 mol CO/kg. The H₂/CO ratio rises to 3.90 for cellulose and 6.15 for lignin, with energy contents reaching 43.16 MJ/kg and 52.91 MJ/kg, respectively. Notably, biomass enhances methane conversion from 25% to over 53% while sustaining a 67% H₂ selectivity. These findings demonstrate that syngas composition and energy content can be precisely controlled via methane co-feeding ratio and temperature, offering a promising approach for sustainable, tunable syngas production. Full article

Biomass reforming under mild conditions for synergistic hydrogen production, driven by renewable solar energy, has rapidly emerged as a promising strategy that not only enables the efficient reutilization of biomass but also facilitates the generation of high-purity hydrogen. In this work, ZnCdS (ZCS) nanoparticles and CoWO₄ (CW) nanocrystals were assembled via a solvothermal method to construct a ZCS/CW S-type heterojunction composite. The resultant materials’ physicochemical characteristics were methodically described. With lignin model compounds (PP-ol) and sodium lignosulfonate as substrates, the ZnCdS/CoWO₄-10% catalyst demonstrated a significant generation of hydrogen activity, producing hydrogen at rates of 223.30 μmol·g⁻¹·h⁻¹ and 140.28 μmol·g⁻¹·h⁻¹, respectively, according to experimental results. The formation of heterojunctions endows composite photocatalysts with higher hydrogen evolution rates compared to single-component catalysts. This is attributed to energy band bending at the interface of the heterojunction, which facilitates efficient charge separation while maintaining strong redox capabilities. High-value compounds like phenol and acetophenone were formed when the oxidation products in the post-reaction lignin model compound solution were subsequently analyzed using high-performance liquid chromatography. Additionally, a convincing mechanism for the catalytic reaction was suggested. It is expected that this study will offer a viable route for the creation of effective photocatalytic materials, high-value organic waste transformation, and sustainable hydrogen production. Full article

The extraction of cellulose from underutilized forest residues can diversify bio-based material supply chains and reduce pressure on commercial pulps. In this study, cellulose was isolated from Tibouchina lepidota (Bonpl.) Baill pruning residues through an alkaline–acid–oxidative protocol, and its suitability for polymeric applications was evaluated. Two granulometric fractions (250 µm and 125 µm) were used; the yields were 4.73 ± 0.12 g and 3.62 ± 0.11 g per 50 g of biomass, equivalent to 90.5% and 92.8% recovery, respectively (fractional remains as bleached pulp after removal of non-cellulosic components). Fourier Transform Infrared spectroscopy (FTIR) showed the disappearance of lignin and hemicelluloses bands and a pronounced β-glucopyranosic signal at 894 cm⁻¹, indicating high purity. Selective solubility in 17.5% NaOH classified the polymer as β-cellulose, suitable for wet spinning and film regeneration. Optical microscopy revealed smooth fibers of 25–50 µm length and 0.5–1 µm diameter, with aspect ratios ≥ 50, indicating favorable morphology for load transfer in composites. Statistical analysis (Shapiro–Wilk, F-test, and Student’s t-test) confirmed the significant influence of particle size on yield (p < 10⁻¹⁵). Overall, T. lepidota residues constitute a viable source of high-purity β-cellulose, whose molecular integrity and microstructure satisfy the requirements of sustainable polymeric manufacturing. Full article

Developing efficient, clean, and sustainable lignocellulose pretreatment technologies is essential for second-generation biofuel production. In this study, we attempted to use downstream-separated binary acetone-water, n-butanol-water, and ethanol-water solutions as the initial liquor for upstream organosolv pulping, in order to achieve the efficient and economic closed-circuit clean fractionation of the lignocelluloses for biological acetone–butanol–ethanol (ABE) production. Parameters, including concentration and temperature of the organosolv pulping, were optimized systematically. Results indicated that the 50 wt% ethanol and 30 wt% acetone aqueous solutions and pulping at 200 °C for 1 h exhibited better corn stover fractionation performances with higher fermentable sugar production. The total monosaccharide recovery (including glucose and xylose) was 50.92% and 50.89%, respectively, in subsequent enzymatic saccharification. While pulping corn stover using n-butanol solution as initial liquor showed higher delignification 86.16% (50 wt% of n-butanol and 200 °C for 1 h), the hydrolysate obtained by the organosolv pulps always exhibited good fermentability. A maximized 15.0 g/L of ABE with 0.36 g/g of yield was obtained in Ethanol-200 °C-50% group, corresponding to 112 g of ABE production from 1 kg of raw corn stover. As expected, the lignin specimens fractionated by closed-circuit organosolv pulping exhibited narrow molecule weight distribution, high purity, and high preservation of active groups, which supports further valorization. This novel strategy tightly bridges the upstream and downstream processes of second-generation ABE production, providing a new route for ‘energy-matter intensive’ and environmentally friendly lignocelluloses biorefineries. Full article

In agriculture, the use of fructans has gained relevance due to their ability to improve plant immunity and resistance to pathogens. However, many studies use high-purity fructans, which makes their application more expensive. In this work, the efficacy of two agave fructans, one food grade from Agave tequilana Weber var. Azul (FT) and the other obtained by semi-craft extraction from A. cupreata (FC) were evaluated in comparison with reagent-grade inulin from dahlia tubers. The effectiveness of their defense response against Phytophthora capsici infection in tomato (Solanum lycopersicum L.) was analyzed by evaluating defense mechanisms, including lignin deposition, hydrogen peroxide (H₂O₂) accumulation, and β-1,3-glucanase and peroxidase activity. The results indicated that foliar application of both fructans showed protection against infection, reducing disease incidence and severity. FT fructans at lower concentration (0.5 g/L) showed the highest protection, followed by FC, while dahlia inulin showed lower effectiveness. An early and progressive accumulation of H₂O₂ was observed in fructan-treated plants, in contrast to the late increase in untreated infected plants. Also, peroxidase activity was higher in the fructan treatments, suggesting a more efficient defense response. Although lignin deposition was not directly correlated with protection against P. capsici, fructans showed potential as resistance inducers. Given their low cost, easy extraction, and zero environmental impact, agave fructans represent a viable alternative for crop protection in sustainable agricultural systems. This study opens the door to their validation in the field and their application in other economically important crops, contributing to biological control strategies with less dependence on agrochemicals. Full article

A key discovery of this study is the strong correlation (r = 0.96) between excitation and emission maxima across chemically distinct clusteroluminogens. All 157 evaluated peaks fall along a single regression line (Ex = 0.844 Em − 12 nm), a pattern that was not valid for conventional fluorophores. This suggests a general principle of clusteroluminescence. We show that in lignocellulosic materials, peak positions reflect chemical interactions: isolated lignin and cellulose showed short excitation and emission wavelengths, while native wood exhibited longer wavelengths. Fungal or photoinduced degradation led to a further red-shift. These effects are attributed to increased molecular heterogeneity, reducing the effective energy gap within the lignocellulosic complex. We conclude that the spectral position reflects the degree of molecular interaction rather than the chemical structure of individual molecules. It may serve as a novel analytical parameter for assessing purity and degradation in a wide range of polymers. Full article

Electrospinning is a simple technique to produce fibers with small diameters. These fibers can be made from different polymers, but the focus is now on biobased materials. In this work, the lignin obtained from Miscanthus x giganteus, an herbaceous plant, was isolated by an Organosolv process leading to a high purity (90%), which is essential for its electrospinning. This lignin also had a carbon content of 72.2% with 24.8% oxygen and a low nitrogen content (1%). The isolated lignin was then solubilized in dimethyl sulfoxide (DMSO). Finally, an optimization step showed that a stable process was possible using a 62% lignin solution in DMSO with a needle-to-collector distance of 20 cm, a flow rate of 0.3 mL/h, a voltage of 25 kV, and a humidity of 35%. Nevertheless, lignin concentrations between 55 and 63% were studied to determine the effect of this parameter on the final fibers. A morphological analysis (SEM-EDX) enabled us to understand both the evolution of the diameter and the effect of dimethyl sulfoxide on the electrospun fibers. This study showed that electrospinning of the lignin obtained from Miscanthus x giganteus was possible, even without any additives. Full article

The valorization of advanced biorefinery lignins remains a significant challenge, owing to the presence of residual carbohydrates. These lignin-associated carbohydrates hinder lignin purification, reduce its homogeneity, and complicate chemical modifications, ultimately limiting the efficient conversion of lignin into high-value products such as chemicals and materials. This study presents a protic ionic liquid-based lignin fractionation process developed using softwood biomass. Triethylammonium methane sulfonate ([N222H][OMS]) was used to fractionate Pinus sylvestris, yielding two distinct fractions: a low-molecular-weight lignin fraction (LF) and a high-molecular-weight lignin fraction (HF). The extracted fractions were comprehensively characterized using nuclear magnetic resonance (NMR) to quantify changes in interunit linkages (β-O-4, β-5, and β-β) and hydroxyl group distribution, whereas methanolysis gas chromatography/mass spectrometry (GC/MS) was used to quantify residual carbohydrates. The fractionation process achieved LF and HF yields of approximately 70.32% and 17.58%, respectively. Further analysis revealed that the HF contained 59.92 ± 2.12 mg/g carbohydrates, whereas the LF contained only 27.37 ± 1.13 mg/g. These findings underscore the effectiveness of the protic ionic liquid fractionation process in reducing carbohydrate impurities and enhancing lignin purity, paving the way for the more efficient utilization of lignin in value-added applications. Full article

Sustainable valorization of lignocellulosic biomass, such as wheat straw (WS), into valuable products is key for efficient resource utilization. This study investigated an integrated strategy combining Irpex lacteus fermentation with subsequent alkali extraction to improve WS valorization. Alkali extraction parameters, including sodium hydroxide concentration, solid-to-liquid (S:L) ratio, temperature, and time, were optimized based on polysaccharide yield and purity. Optimal conditions were identified as 0.8 mol/L sodium hydroxide, a 1:25 S:L ratio, 90 °C, and 1 h, yielding 6.63% polysaccharides with 52.01% purity. Compared to untreated straw, the combined fermentation and alkali extraction treatment significantly altered the WS residue’s composition and structure, substantially reducing hemicellulose and acid detergent lignin while consequently increasing relative cellulose content. This enhanced cellulose accessibility resulted in a markedly improved glucose yield upon enzymatic hydrolysis, reaching 586 g/kg dry matter for the residue after combined treatment. Demonstrating a strong synergistic effect, this yield represents a 5.42-fold increase compared to untreated WS and a 3.30-fold increase compared to solely fermented straw. Analyses of SEM, FTIR, and XRD confirmed that the integrated treatment effectively disrupted the lignocellulosic structure by removing lignin and hemicellulose. This created a more porous morphology and increased cellulose exposure, which was deemed more critical for hydrolysis than the observed 18.58% increase in the cellulose crystallinity index relative to untreated straw. Thermogravimetric analysis further reflected these structural and compositional changes through altered thermal decomposition profiles. Therefore, integrating polysaccharide extraction with fungal fermentation is a highly effective strategy for improving resource efficiency in WS valorization. This approach enables the efficient co-production of valuable polysaccharides alongside significantly boosted platform sugar yields, offering a promising route towards more economically viable and sustainable WS utilization. Full article

The chemical industry’s transition towards sustainability necessitates the development of eco-friendly processes that can replace petrochemical derivatives. Lignin, the second most abundant plant polymer, has potential as a renewable alternative to phenolic compounds. This study investigates lignin precipitation from softwood black liquor using five organic acids (acetic, citric, lactic, malic, and oxalic) as a sustainable alternative to sulfuric acid. The precipitated lignins were subjected to comprehensive chemical and thermal characterization, revealing higher total phenolic content and enhanced reactivity when organic acids were employed. Notably, organic acid-precipitated lignins demonstrated comparable or superior purity, with ash contents below 0.50%, compared to 3.28% observed for sulfuric acid-precipitated lignin. These findings suggest that organic acids are a viable and greener alternative for lignin precipitation, promoting higher purity and yield, thus supporting lignin valorization efforts. Full article

In parallel with the worldwide issues of malnutrition and food waste, society at large focuses on the advantages of ‘recycling’ food waste. Brewer’s spent grain (BSG), a primary byproduct of the brewing industry, is produced in large quantities in many regions of the world, leading to environmental issues. The present study aimed at valorizing BSG through bioactive compound extraction using more traditional approaches, including Soxhlet extraction, recrystallization, and salting-out adsorption for proteins and lactic purification. The extraction rate of total dietary fiber (TDF) was 93.3%. FTIR analysis showed specific structural vibrations of fiber with C-O and C-O-C attachments in hemicellulose, C-H bends in lignin, and various bending patterns in tannins and fatty acid esters. Hemicellulose (8245.2 mg/L), lignin (10,432.4 mg/L), and cellulose (13,245.4 mg/L) were extracted with rates of 54.9%, 69.5%, and 88.3%, respectively. These bioactive compounds extracted from BSG could be utilized in food and nutraceutical products based on their purity. The analysis of extracted bioactive components confirmed the presence of arachidic acid (C20:0), oleic acid (C18:1), linoleic acid (C18:2), myristic acid (C14:0), pentacyclic acid (C30:0), palmitic acid (C16:0), margaric acid (C17:0), gallic acid, catechol, ellagic acid, acetyl sialic acid, benzoic acid, and vanillin. These findings highlight the valorization potential of BSG, a previously regarded waste material, as a source of active biocomponents. This is consistent with the principles of the circular economy by reducing waste in the environment and supporting tangible sustainability in food systems. The efforts made in the current study in utilizing BSG are part of the fast-growing area of food waste recycling and provide a way to avoid waste and create added value. Full article

Natural rubber (NR) is in high demand due to its excellent elasticity and physical and mechanical properties, but production is limited and NR is in short supply. There is an urgent need to find new alternative rubber sources. Taraxacum kok-saghyz (TKS), as a green, renewable, widely planted and high content rubber producing plant, has shown broad application prospects. The extraction process is the key to developing efficient, green, and high-purity Taraxacum kok-saghyz Natural Rubber (TKNR) to replace NR in various applications. In this study, TKS roots were processed through repeated boiling to remove inulin, followed by alkaline treatment with potassium hydroxide (KOH) to isolate lignin and facilitate cell wall disruption. Subsequent enzymatic hydrolysis using pectinase and cellulase enabled the dissolution of root-structure carbohydrates, thereby obtained TKNR. Structural characterization of TKNR was conducted and compared with that of NR. The results showed that the combined alkaline and enzymatic extraction methodology effectively isolates TKNR from TKS roots. Structural analysis reveals that TKNR closely resembles NR, having comparable molecular weight and distribution, crystallinity, and crosslinking networks, with both polymers primarily consisting of cis-1,4-polyisoprene. Full article

In recent years, lignin derived from lignocellulosic biomass has emerged as a critical component in modern biorefinery systems. The production yield and reactivity of lignin are critical factors for advancing the research and development of lignin-derived biochemicals. The recovery of high-purity lignin, along with carbohydrates, is accomplished through the application of various advanced pretreatment techniques. However, biological pretreatment using lignin-degrading enzymes to facilitate lignin depolymerization is an environmentally benign method for the sustainable production of valuable products that occurs under mild conditions with high substrate specificity. The current review presents the role of biocatalysis in lignin valorization, focusing on lignin-degrading enzymes that facilitate different bond cleavage in the lignocellulosic biomass. The review also highlights the recent advancements in enzyme engineering that have enabled the enhancement of enzyme stability and catalytic efficiency for improving lignin valorization processes. Furthermore, the integration of omics technologies that provide valuable insights into the microbial and enzymatic pathways involved in lignin degradation is presented. The challenges and future prospects in this emerging field of study for a biorefinery concept are also outlined for improving lignin depolymerization efficiency. Full article

This work aimed to extract nanolignin from green coconut husk and fiber using the acetosolv method, with the aim of transforming waste into high-value-added products and promoting sustainability and bioeconomy. The acetosolv pulping was carried out in two stages, varying temperature conditions and the presence or absence of extractives. Lignin was obtained by precipitation and subsequently characterized through chemical and morphological analyses. The analyses of the primary components of the coconut husk and fiber demonstrated lignin, cellulose, and hemicellulose contents of 40%, 15.90%, and 15.86%, respectively. Then, nanolignin was produced through ultrasonication (850 W for 10 and 20 min). The characteristics of the obtained products were analyzed, considering the influence of two temperatures (100 °C and 120 °C) and the need for a pretreatment step (removal of extractives). The temperature variation between 100 °C and 120 °C, as well as the presence of extractives, did not significantly influence the lignin quality or extraction efficiency. The nanolignin produced under this condition was subjected to the DLS technique to determine the hydrodynamic diameter and polydispersity of the nanoparticles obtained, with an average diameter of 533.75 ± 15.12 nm after 20 min of ultrasonication. The purity of the lignin was confirmed by analyses such as the Klason lignin and ash content, which presented values of 78.82 ± 0.81% and 0.55 ± 0.26%, respectively. FTIR analyses revealed typical lignin characteristics, such as the presence of ketone groups, aromatic structures, and methoxylation, while thermograms confirmed the thermal stability of the lignin. Acetosolv pulping proved to be particularly interesting, preserving good quality lignin and allowing for partial recovery of the solvents used, promoting the sustainability and energy efficiency of the process. Full article