Search Results (416)

As a key constituent of lignocellulosic biomass, the role of hemicellulose in anaerobic digestion (AD) remains inadequately characterized, particularly regarding its methane potential and degradation process patterns. This study systematically characterized the AD performance of hemicellulose using xylan as a representative substrate. The results showed that xylan achieved a high methane potential of 350–390 mL/g VS and 89.57% biodegradability, exhibiting a shorter lag phase (λ) and higher reaction rate (k) than other biomass fractions. Substantial acetic acid and ethanol accumulated within the first 24 h, while late-stage dissolved organic matter (DOM) shifted toward complex lignin/CRAM-like. The results of microbial dynamics indicated that the collaborative interaction among Anaerobium, Lactobacillus, and Clostridium accelerated xylan transformation. While methanogenesis was predominantly driven by the acetoclastic route (specifically Methanosarcina), hydrogenotrophic Methanobacterium thrived during temporary pH fluctuations. This work serves as a valuable guide for developing high-performance strategies in industrial lignocellulosic biogas plants. Full article

Obtaining enzymes through bioconversion depends on a complex relationship between the microorganisms and the biomass used. Here, we evaluate xylanase production by diverse actinobacterial species, cultivated using xylan as the sole carbon source and complex media containing sorghum as the substrate. Fifty-three actinobacteria were tested for xylanase production in a solid medium. Seventeen strains produced xylanase and were tested for their ability to produce xylanase, total cellulases (filter paper activity, FPase), and endoglycanase in submerged culture using a defined liquid medium. The best xylanase-producing species was Streptomyces capoamus, yielding 24 IU·mL⁻¹. For FPase, Streptomyces sp. showed the highest yield (1.12 IU·mL⁻¹); for endoglycanase, the best producer was Streptomyces ossamyceticus (0.99 IU·mL⁻¹). When sweet sorghum was used alone, S. curacoi, S. ossamyceticus, and S. capoamus showed xylanase activities of 4.5 IU·mL⁻¹, 4.4 IU·mL⁻¹, and 0.8 IU·mL⁻¹, respectively. However, FPase activity was not detected under the assay conditions. The results showed that there is an intraspecific difference in xylanase, endoglucanase, and FPase production by actinobacteria, with the species S. curacoi, S. ossamyceticus, and S. capoamus able to use sorghum as a carbon source, demonstrating biotechnological potential. Full article

Agricultural leftovers from oilseed crops represent an underutilized lignocellulosic resource for integrated biorefinery. In this work, rapeseed straw (RS) and sunflower stalk (SS) were evaluated as raw materials for the simultaneous recovery of hemicelluloses, lignin, and cellulose-rich fibers. Direct soda pulping (20% NaOH, 160 °C, 45 min) or a combination of soda pulping with water pretreatment or alkaline extraction (water or 2% NaOH, 110 °C, 40 min) were the methods used in the process. Acid precipitation was used to remove lignin from the process fluids, whereas ethanol was used to separate hemicelluloses. FTIR spectroscopy, HPLC of acidic hydrolysates, and chemical composition analysis were used to analyze solid fractions and recovered biopolymers. The combination alkaline extraction–soda pulping produced the greatest material removal: 55% for RS and 70% for SS. Xylan was the main component of the isolated hemicellulose fraction: 44.86% for RS and 40.09% for SS. Paper sheets produced from the resulting pulps exhibited tensile strength indices of 35–55 N·m/g and burst indices of 1.1–2.4 kPa·m²/g, meeting requirements for hygiene and fluting packaging papers. These results prove that RS and SS are suitable feedstocks for integrated, multi-stream biorefinery, enabling the concurrent production of paper-making fibers and value-added biopolymers. Full article

The organisation of hemicelluloses within the pollen intine of many monocots remains inadequately characterised, partly due to the masking of epitopes within complex wall matrices. In this study, mature pollen grains of Gagea lutea (L.) Ker-Gawl. were analysed using immunofluorescence and immunogold technique with a variety of monoclonal antibodies that target xyloglucan (LM15, LM24, LM25, CCRC-M48), heteroxylan (LM10, LM11), heteromannan (LM21, LM22), and xylan (CCRC-M138). Semithin sections of LR White were examined both untreated and following a sequential enzymatic pretreatment, which included alkaline de-esterification followed by treatment with pectate lyase (RbPel1A) and endo-β-mannanase 5A. In untreated pollen, xyloglucan-related epitopes were identified within the intine, accompanied by additional intracellular labelling for LM15, and LM25; while for LM24 signal was only to the intine ring. Conversely, CCRC-M48 exhibited a more punctate distribution. Neither xylan- nor mannan-related epitopes were detected in the wall or intracellularly. The enzymatic digestion significantly altered the detectability of epitopes, resulting in an increase in continuous wall labelling within the intine across multiple probes. These findings indicate that enzymatic modification of pectic and mannan components has a considerable impact on the apparent distribution of hemicellulose epitopes within the pollen wall of G. lutea. Together, these results expand the still limited in situ immunolocalisation evidence base for hemicellulose-related epitopes in pollen, and provide a practical framework for interpreting digestion-dependent changes primarily in terms of epitope accessibility within the intine matrix. Full article

The digestive gland of Venus flytrap consists of various types of specialized cells. Secretory cells form two layers: the first is a more external outer layer and the second is an internal layer that is connected to stalk cells. Our goal was to check whether the position/location of cells is essential in terms of cell wall composition (whether cell wall microdomains exist). We also focused on the structure of cell wall ingrowths in secretory cells. To achieve this, the localization of the cell wall components in the cell walls of gland cells was performed using the immunolabeling technique and confocal microscopy. It has been found that cells within the gland head are not equal. Their location determines the composition of their cell walls in terms of the presence of various epitopes. The cell walls of the secretory cells in the outer layer were deficient in epitopes recognized by antibodies, including JIM5 (low methylesterified homogalacturonans), CCRC-M38 (low methylesterified homogalacturonans), LM5 (galactan), and CCRC-M48 (xyloglucan), which contrasted with the cell walls of the cells in the inner layer. In terms of the occurrence of pectic homogalacturonans, cell wall ingrowths constitute cell wall microdomains. The digestive glands of Dionaea muscipula exhibit pronounced cell wall microdomain organization, with distinct distributions of pectins, hemicelluloses, and arabinogalactan proteins across different glandular layers. These compositional differences reflect functional specialization in secretion, absorption, and structural support. Full article

Xylanases (EC 3.2.1.8) are value-added enzymes essential for biomass deconstruction and are widely used in the pulp and paper, food, feed, and biofuel sectors. This review provides a comprehensive analysis of the current state and future prospects of xylanase research and application. It begins by examining the structural diversity of xylan substrates and the corresponding classification of xylanase enzymes, their catalytic mechanisms, and methods for their functional study, such as inhibitor analysis. The discussion then covers the challenges and methods involved in the purification of xylanases from complex biological mixtures. While natural microbial sources (fungi and bacteria) remain important, the limitations of wild-type (WT) strains for industrial production are highlighted. The review assesses the most common recombinant production systems, including Escherichia coli, Bacillus subtilis, and Komagataella phaffii, comparing their advantages for high-yield enzyme production. Finally, the paper focuses on protein engineering strategies as powerful tools for enhancing key enzyme properties (thermostability, specific activity, and pH tolerance). By integrating fundamental knowledge with applied technological approaches, this review underscores the critical role of xylanases in industrial biotechnology and identifies future research directions for their optimization. Full article

Wet coffee pulp residues (WCPRs) are typically underutilized, and their accumulation increases alongside coffee production, generating significant environmental impacts. This study proposes a sustainable valorization approach through hydrothermal treatment followed by membrane filtration for the production of xylooligosaccharides (XOSs). Extractive-free WCPR contained 35.4% structural carbohydrates (20.4% cellulose and 15.0% hemicellulose) and 27.0% lignin. Hydrothermal treatments (180 °C, 3 °C min⁻¹, 15–60 min) were performed with and without citric acid as an organic catalyst. The acid-assisted treatment (T4) enhanced hemicellulose depolymerization and xylose release (16 g·kg⁻¹ dry biomass), whereas milder, non-acidic conditions (T3) promoted the selective formation and recovery of short-chain XOS, reaching cumulative biomass-normalized yields of up to 14 g·kg⁻¹ of xylobiose (X2) and 9 g·kg⁻¹ of xylotriose (X3). Subsequent membrane processing (UF–DF–NF) enabled progressive purification and enrichment of XOS fractions. Diafiltration was identified as the main step governing XOS enrichment, whereas nanofiltration primarily refined separation by directing monomeric sugars to the permeate rather than substantially increasing XOS yields. Additionally, Multiple Factor Analysis (MFA) integrated process and compositional variables, explaining 79.6% of the total variance. Dimension 1 represented process intensity and xylose transport, while Dimension 2 reflected molecular-weight-driven XOS fractionation. The acid-assisted process (T4) exhibited a distinct multivariate signature, characterized by enhanced carbohydrate mobilization and improved XOS recovery with reduced dependence on dilution. Overall, coupling hydrothermal pretreatment with membrane fractionation proved to be an efficient, and environmentally friendly strategy for coffee by-product valorization, consistent with hemicellulose-first biorefinery models and the principles of the circular bioeconomy. Full article

Comparative omics analysis offers one of the most direct and effective approaches to gain novel insights into crop traits, facilitating candidate gene identification and crop improvement. Verticillium dahliae causes one of the most globally devastating crop diseases, the Verticillium wilt (VW). However, comparative transcriptome resources regarding VW resistance remain scarce in a major host species potato. To address this knowledge gap, we provide a comprehensive comparative RNA-seq analysis of VW resistance between a VW-resistant and -susceptible potato cultivar (LS8 and SP, respectively). VW inoculation induced dramatic transcriptomic changes, resulting in 14,310 differentially expressed genes (DEGs) in LS8 and 21,739 DEGs in SP. With the time-series analysis, we disentangled the VW-associated transcriptomic responses from those reflected LS8-SP cultivar differences. Particularly, LS8 featured a rapid response of phytohormone salicylic acid and defense-related specialized metabolites at 1 day post inoculation (dpi), followed by large-scale metabolic reprogramming, including carbohydrate and choline metabolism and enhanced biosynthesis of secondary cell wall components (e.g., hemicellulose, xylan, cuticle, suberin, and wax). Furthermore, we identified highly expressed VW-responsive potato phenylalanine ammonia-lyase genes (StPALs) and revealed the higher PAL activities in LS8 associated with VW resistance. Overall, our results provide the first transcriptomic insights into VW resistance in potato and new candidate genes regarding VW resistance. Full article

Agro-industrial chestnut waste derived from chestnut processing is usually discharged without further use. However, these residues are attractive due to their high-value composition, rich in sugars and lignin. Among these residues, chestnut burrs (CB) represent a promising feedstock for biorefinery applications aimed at maximizing the valorization of their main constituents. In this study, we propose an environmentally friendly approach based on deep eutectic solvents (DES) formed by choline chloride and urea (ChCl/U) (1:2, mol/mol) for the selective deconstruction of lignocellulosic architecture, followed by enzymatic hydrolysis to release second-generation (2G) fermentable sugars. Pretreatments were applied to raw CB, washed CB (W-CB), and the obtained solid fraction after prehydrolysis (PreH). Structural and morphological modifications, as well as crystallinity induced by DES pretreatment, were characterized using attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), field emission scanning electron microscopy (FE-SEM), and X-ray diffraction (XRD). Remarkable results in terms of effectiveness and environmental friendliness on saccharification yields were achieved for PreH subjected to DES treatment for 8 h, reaching approximately 60% glucan and 74% xylan conversion under the lower enzyme loading (23 FPU/g) and liquid-to-solid ratio (LSR) of 20:1 studied. This performance significantly reduces DES pretreatment time from 16 h to 8 h at mild conditions (100 °C), lowers the LSR for enzymatic hydrolysis from 30:1 to 20:1, and decreases enzyme loading from 63.5 FPU/g to 23 FPU/g, therefore improving process efficiency and sustainability. Full article

The study explores γ-valerolactone (GVL) pulps as a sustainable approach to producing microfibrillated (MFC) and nanofibrillated (NFC) cellulose from sugarcane bagasse, a widely available agro-industrial by-product. Pulp was obtained by acid-catalyzed organosolv delignification with a GVL–water system. MFC was generated through a simple disc refiner, while NFC was produced by TEMPO-mediated oxidation followed by mechanical treatment in a colloidal mill. NFC and MFC produced using the same methodology from a commercial sugarcane totally chlorine-free (TCF) soda–anthraquinone (soda–AQ) pulp served as a reference. Structural and physicochemical characterization involved optical transmittance, turbidity, conductimetry, X-ray diffraction, viscosity, FTIR, carboxyl content, cationic demand, degree of polymerization, and morphology by scanning electron microscopy (SEM). Results demonstrated that xylan and residual lignin contents influenced MFC formation, and the NFC showed properties comparable to those of the commercial pulp with fewer fibrillation passes. The study highlights GVL pulping as a greener, efficient alternative to conventional processes, opening new pathways for producing viscosity-controlled nanocellulose suspensions suitable for advanced applications. Full article

β-D-xylosidase (BXL) is a key enzyme involved in xylan degradation and plays crucial roles in plant development and stress responses. However, its functional roles in potato (Solanum tuberosum) remain poorly understood. In this study, we performed a genome-wide identification of the StBXL gene family and identified eight StBXL genes distributed across five chromosomes. A phylogenetic analysis classified these genes into four groups. Conserved motif and domain analyses indicated functional conservation among StBXL proteins. Analyses of cis-acting elements in the promoters and expression profiles of StBXL genes in various plant tissues under different stress treatments revealed their spatiotemporal expression patterns, as well as potential roles in phytohormone signaling and stress responses. Alkali stress significantly inhibited the expression of StBXL4 and StBXL5. The overexpression of StBXL4 enhanced the sensitivity of potato seedlings to alkali stress, whereas the overexpression of StBXL5 showed no significant phenotypic differences under the same conditions. These results suggest that StBXL4 acts as a negative regulator of the alkali stress response in potato. This study fills the research gap regarding the potato StBXL gene family and provides valuable insights for the molecular breeding of alkali-tolerant potato varieties. Full article

This study focused on optimising the saccharification of cardoon mixed residues through acid or base-catalysed steam explosion, using a Response Surface Methodology (RSM) to optimise the main process parameters. Despite the increasing interest in cardoon as a lignocellulosic feedstock, its efficient fractionation remains challenging, with limited cellulose hydrolysis and incomplete hemicellulose recovery under non-optimised steam explosion conditions. Therefore, a systematic evaluation of catalytic severity is required to improve biomass valorisation. H₂SO₄-catalysed steam explosion significantly improved glucan hydrolysis in the following enzymatic saccharification process, achieving 78 mol% glucose yield after a pretreatment carried out at 200 °C, 5 min, and 25 mM catalyst concentration. Xylan recovery required a higher catalyst concentration of 50 mM and temperatures lower than 220 °C to avoid the dehydration reaction of xylose to furfural. The optimal conditions for maximising glucose and xylose yields were 196 °C for 5 min with 50 mM H₂SO₄, resulting in 80.5 mol% glucose yield and 70.3 mol% xylose yield. Alkaline-catalysed steam explosion at 200 °C with 25 mM NaOH increased the enzymatic hydrolysis of glucan and favoured the production of lignin with a higher syringyl/guaiacyl ratio, making it more reactive. Overall, this research provides valuable insights into catalytic steam explosion coupled with the enzymatic saccharification step for the complete valorisation of lignocellulosic cardoon residues. Full article

Plant cell wall polysaccharides (PCWPs) serve as an abundant but recalcitrant carbon source for many microbes living in the gut of humans and animals. An adhesion to PCWPs is common in gut bacteria and can even be observed in the lactobacilli, which are supposed to promote the growth competence of these non-PCWP degraders because of the facilitated acquisition of newly released oligosaccharides. Nevertheless, the binding of molecules of lactobacilli to PCWPs and the underlying mechanisms remain largely unknown. By analyzing the transcriptome of Lactobacillus brevis grown in xylan supplemented with a xylanase, a gene was identified to encode a putative S-layer PCWP-binding protein (Lb1145). Lb1145 was predicted to have four domains, among which domains 1 and 2 were responsible for binding PCWPs. The binding was nonspecific, since structurally distinct PCWPs, e.g., cellulose, xylan, mannan, and chitin, and even lignin, were all bound by Lb1145. Both of the two N-terminal domains have a high pI, and we demonstrated that a non-enzymatic glycosylation-like process plays an important role in binding. Compared with another L. brevis surface protein, i.e., the WxL protein Lb630, Lb1145 displayed a binding preference for the phloem sieve tube in the wheat stem section. Moreover, Lb1145 could bind ten strains within the Lactobacillus, Enterococcus, Pediococcus, and Bacillus genera among the seventeen selected gut bacterial species. An analysis of the reported S-layer proteins from the Gram-positive bacteria (lactobacilli and bifidobacteria) and outer membrane proteins from the Gram-negative (Bacteroides fragilis and Prevotella intermedia) indicated that bacterial cell surface proteins with high pI values are not rare. The high pI-based and non-enzymatic glycosylation-like process-mediated binding represents a new paradigm and may be popular in gut bacterial surface proteins binding to PCWPs, with important physiological implications in growth competition in the gut microbiota. Full article

Flowering often perturbs carbon allocation in sugarcane, yet its transcriptomic–metabolomic basis remains unclear. We profiled two contrasting cultivars, Gui Tang 16-3285 (sugar increases during flowering) and Gui Tang 44 (sugar decreases), sampling apical tissues at five stages (Non-spikelet-bearing stage (NSB), Early booting stage (ESB), Late booting stage (LSB), Tasseling stage (TS), and Flowering stage (FS)). RNA-seq and untargeted LC–MS revealed a strong stage/genotype structure (PCA) with high reproducibility. Pairwise contrasts (FS vs. earlier stages) and time series clustering (Mfuzz) showed extensive, stage-resolved reprogramming with small cross-cultivar overlaps. GO/KEGG indicated that GT16 is enriched for central carbon processes and glucose response, whereas GT44 favors cell-wall remodeling (xylan/xyloglucan), amino/nucleotide sugar, and phenylpropanoid pathways. Integrated analysis identified opposing temporal features across omics layers: in GT16, late-rising metabolites—including sedoheptulose—were consistent with enhanced pentose phosphate/Calvin coupling that regenerates fructose-6-phosphate for sucrose biosynthesis; in GT44, early activation of wall and secondary sinks, together with trehalose/(trehalose-6-phosphate) T6P signatures, paralleled declining soluble sugars. Across cultivars we resolved 11 and 18 genes in reciprocal opposite-trend sets (most with clear temporal order) and eight vs. five metabolites with mirrored dynamics, nominating actionable biomarkers (e.g., sedoheptulose/S7P) and regulatory nodes. These results provide a mechanistic framework linking flowering stage to carbon partitioning and suggest practical levers—timing growth moderation/ripeners, prioritizing sucrose phosphate synthase/Sucrose Phosphate Phosphatase, tempering wall flux, to sustain sucrose during reproductive development and inform breeding for high-sugar, flowering-resilient ideotypes. Full article

This study examines the thermal modification (TM) of European black alder (Alnus glutinosa) wood boards measuring 1000 × 100 × 32 mm. The TM was carried out in a nitrogen atmosphere under an initial pressure of 4 bar at 160 °C for 60, 120, and 180 min, as well as at 170 °C for 30 and 60 min. The TM process resulted in mass loss and volumetric changes with shrinkage observed across all anatomical directions. Water uptake decreased significantly, with the cell wall’s total water capacity dropping from 35% to a range of 14%–27%. Dimensional stability was improved by between 21% and 61%. The TM wood showed a reduction exceeding 50% in both volumetric swelling and equilibrium moisture content relative to the unmodified specimens. A marked decline in the modulus of rupture was observed, especially in samples treated at 160 °C for 180 min and at 170 °C. Conversely, the modulus of elasticity exhibited a slight upward trend, though the changes were not statistically significant. Brinell hardness revealed a pronounced difference between the tangential and radial orientations, with the tangential surface displaying distinctly lower hardness. Chemical analysis indicated a notable increase in acetone-soluble extractives and reductions in the xylan, mannan, and acetyl groups, reflecting structural alterations in hemicelluloses. Full article