Search Results (285)

Rice straw is a highly produced agricultural waste with a high cellulose content, which can be used as a cellulose source. Nevertheless, more sustainable extraction and purification strategies are needed to reduce the consumption of chemicals during the production of cellulose-derived materials. In this way, an integrated method based on subcritical water extraction and bleaching with hydrogen peroxide was used for isolating cellulose from rice straw. The cellulose fibres obtained were converted into microcrystalline cellulose (MCC) by applying acid hydrolysis with HCl 2N at 60 °C to reduce the fibre amorphous fraction. High cellulose purity (86%) and crystallinity (67%) were obtained in the isolated fibres. The influence of high-shear homogenisation (12,000 rpm) during hydrolysis was analysed, compared to mild stirring (350 rpm) at different times (30 and 60 min). High-shear homogenisation greatly accelerated the hydrolysis process of the amorphous fraction of the fibres, contributing to the reduction in particle size (to about 10 µm), defibration, increased crystallinity (70–72%), and shorter cellulose chains (92,400–61,600 g/mol) for a given treatment time. After 30–60 min of treatment, the resulting MCCs exhibited properties within the range reported for commercial AVICEL, with greater reinforcing performance in PHBV films. These MCCs resulted in lower water vapour permeability, while improved oxygen barrier properties were mainly observed for those obtained under high-shear hydrolysis conditions. Full article

The European construction sector accounts for approximately 40% of EU final energy consumption and around 36% of lifecycle CO₂ emissions, creating structural demand for low-carbon alternatives consistent with the European Green Deal and the revised Energy Performance of Buildings Directive. This article presents a structured multi-criteria assessment of seven bio-based construction material categories producible within the EU—wood fibre/cellulose insulation, expanded cork agglomerates (insulation corkboard), mass timber (CLT and Glulam), hemp–lime composites (hempcrete), straw bale systems, mycelium-based composites, and cellulose aerogels—evaluated across twelve sub-criteria organised under three equally weighted pillars: environmental impact, economic opportunity, and social value. The analysis integrates durability maturity as a primary market-access variable, fire performance under Wildland–Urban Interface (WUI) exposure conditions, seismic risk compatibility, and EU regional demand heterogeneity. Composite scores are calculated by summing individual criterion scores, with pillar sub-totals shown explicitly. A sensitivity analysis under three alternative pillar-weighting scenarios, a single-criterion perturbation analysis, a Monte Carlo simulation, and a TOPSIS method comparison collectively test the robustness of rankings. Results indicate that wood fibre/cellulose insulation, expanded cork agglomerates, and hemp–lime composites constitute the highest-impact portfolio under baseline and environmental priority weighting; under economic priority weighting, mass timber displaces hemp–lime in the top 3. Under environmental priority weighting, cork achieves the highest composite score of any material, driven by its perfect environmental pillar sub-score and the regenerative carbon sequestration of the cork oak. All four robustness tests confirm that wood fibre, cork, and hemp–lime occupy the top 3 positions across all weighting scenarios—with cork rising to first and wood fibre dropping to third under environmental priority weighting—and that the additive scoring method produces rankings identical to those generated by the TOPSIS method. Full article

Hakea sericea is one of the most aggressive invasive shrubs in Mediterranean ecosystems, producing large quantities of lignocellulosic residues during control operations. This study evaluates thermochemical liquefaction as a valorisation route for this biomass, linking biomass conversion with invasive species management. Whole-plant material was liquefied through acid-catalysed reactions using 2-ethylhexanol as the solvent and p-toluenesulfonic acid as the catalyst. A response surface methodology design was used to assess the effects of temperature, reaction time, and catalyst loading on conversion efficiency. The biomass contained 35.92% cellulose, 32.29% hemicellulose, and 17.36% lignin. Liquefaction yields ranged from 15.59% at 120 °C for 30 min to 82.7% at 160 °C for 90 min, with conversions above 70% achieved within 30 min at higher catalyst concentrations. The regression model explained 87.5% of the variability in liquefaction performance. Spectroscopic and thermal analyses confirmed extensive depolymerisation of lignocellulosic polymers and the formation of an aliphatic-rich bio-oil, with 57.5% of proton signals located in the alkane region of the ¹H NMR spectrum. The bio-oil exhibited a higher heating value of 31.91 MJ kg⁻¹, corresponding to an energy recovery of about 85%. Microscopic observations showed strong structural disruption of plant fibres. Overall, the results demonstrate efficient conversion of H. sericea biomass into energy-dense liquid products, supporting its use in invasive species control strategies. Full article

The presented study aimed to fully characterise berry powders derived from raspberry, blackberry and strawberry (RB, BB, SB) as well as raspberry and blackberry seed powders (RBS, BBS) in terms of proximate composition, the individual profile of minerals, sugars, organic and fatty acids, and phenolic and volatile compounds. Additionally, testing of powders’ colour and antioxidant activity, as well as spectroscopic analysis, were also performed. Higher total and individual sugars, organic and phenolic acids, flavonols and anthocyanins content distinguished berry powders from the seed powders. Individually, RB contained significant amounts of citric and chlorogenic acids, BB was superior in cyanidin-3-O-glucoside and quercetin-3-O-rutinoside content, while SB was characterised by high sucrose, fructose, omega-3, and mineral (Ca, Mg, Fe) content. Berry seed powders exhibited remarkable TDF content, beneficial PUFA/SFA ratio, lighter colour, higher individual flavan-3-ols quantity, TPC and DPPH activity compared to berry powders. Mentioned discrepancies between berry and berry seed powders on a compositional level were also visible on ATR-FTIR spectra across all detected regions reflecting bonds attributed to cellulose, lipids, phenols and sugars. Pleasant, predominantly green, fruity and floral aromas were associated with berry powders, whilst additional herbal notes were characteristic of berry seed powders, all derived from the alcohols, aldehydes, esters and ketones as paramount volatile compounds. All examined powders can bear a nutritional claim of “high in” fibre (20.47–65.33%) and Mg (114.52–128.70 mg/100 g), enabling the design of food products packed with nutrients and bioactives while simultaneously reducing fresh fruit and fruit-processing waste. Full article

The durable enzyme functionalisation of cellulosic fibres is often limited by enzyme deactivation under alkaline processing and insufficient wash resistance. Here, a cold pad–batch (CPB)-compatible route integrates reactive dyeing and lysozyme anchoring by using the commercial bifunctional dye C.I. Reactive Red 195 (MCT/VS) as an interfacial mediator to build a cellulose–dye–lysozyme ternary layer. The dye is first fixed on cotton, and residual electrophilic motifs are proposed to facilitate subsequent coupling with nucleophilic residues in lysozyme. A nine-run, four-factor/three-level orthogonal design was used to identify a practical processing window; under the selected condition, an ELISA-equivalent releasable lysozyme level of 53.8 U/L was achieved together with moderate colour strength (K/S = 6.5). The treated fabrics exhibited 96.5% inhibition against Escherichia coli and >99.9% against Staphylococcus aureus and retained antibacterial functionality after five ISO 105-C06 laundering cycles. Textile-relevant properties were preserved, including colour fastness (Grade 4–5), tensile strength retention (~86%), and capillary wicking close to pristine cotton. This dye-mediated strategy offers a practical route to wash-resistant bioactive interfaces on cellulose fibres and is extendable to regenerated cellulose and wood-pulp-derived cellulosics. Full article

The mechanical recycling of mono-material biaxially oriented polypropylene (BOPP) packaging films produces recycled polypropylene (rPP) with degraded properties, limiting its use in higher-performance applications. This study investigates rPP reinforcement with 6–12 µm microcellulose fibres (MCFs, 2–10 pbw) and microcellulose-derived biochar (BC, 5–20 pbw), characterized by DSC, TGA/DTG, MVR/MFR, temperature-dependent rheology, mechanical testing and water contact angle (WCA) measurements. Both fillers acted as heterogeneous nucleating agents, shifting crystallization by up to 4 °C and increasing crystallinity by 2–4%. MCF introduced an additional low-temperature degradation step, whereas BC increased onset and peak degradation temperatures by up to 20 °C and increased char yield. Low MCF loadings increased MVR/MFR by 20–25% and reduced melt viscosity, while BC decreased flow indices by up to 50% and stiffened the melt. Tensile and flexural moduli increased by 15–25% with MCF and 40–50% with BC, with a stiffness–toughness trade-off at the highest BC contents. MCF reduced the water contact angle to 63.0° at 10 pbw, while BC increased it to 108.1° at 20 pbw, indicating opposite effects on surface wettability. Converting a single cellulosic feedstock into fibrous or carbonised fillers enables bio-based upgrading of rPP, in line with circular economy principles. Full article

The use of invasive plant species for papermaking presents both environmental and economic opportunities, particularly for companies seeking to introduce sustainable materials. This study examined whether paper made from cellulose fibres of Japanese knotweed is suitable for printing business elements such as logos in specific red colours. The physical, mechanical, and optical properties of the paper were compared with those of standard office and commercial Xerox paper. Two printing techniques—electrophotography and inkjet printing—were tested, and the colour differences (CIE colour difference, ΔE) between the reference logo and the prints, with and without the International Colour Consortium (ICC) colour profile, were evaluated. The results showed that the low whiteness and high porosity of the knotweed paper negatively affected colour reproduction, especially in inkjet printing, where even manually optimised profiles did not yield satisfactory results (minimum ΔE > 23). Electrophotography performed better but still had limitations. It was concluded that Japanese knotweed paper is not suitable for professional reproduction of demanding colour elements without additional processing, although it has potential for sustainable applications with lower visual requirements. Full article

N-methylmorpholine N-oxide (NMMO monohydrate) is widely used for cellulose fibre production, as in the Lyocell process. However, fibre spinning from denim wastes remains significantly more complex due to its higher viscosity, the presence of indigo dye, and NMMO’s temperature sensitivity. These factors together create serious challenges for denim dissolution and fibre regeneration. This study presents a comprehensive rheological and structural characterisation of regenerated cellulose fibres derived from waste denim dissolved in NMMO. Oscillatory and steady-state rheological tests were conducted across concentrations (4–8 wt%) and temperatures (60–90 °C) to determine optimal spinning conditions. A 6% denim/NMMO solution at 80 °C displayed the most favourable rheological balance within the investigated concentration window (4–8 wt%), moderate complex viscosity, well-defined viscoelastic transitions, and a Tan δ value (~0.94) consistent with stable jet formation in air-gap spinning. Steady shear tests confirmed strong shear-thinning behaviour and mechanical predictability, essential for spinneret extrusion. Thermal ramp experiments validated 80 °C as the upper safe limit, balancing flow processability with structural integrity while avoiding solidification or NMMO degradation. The identified rheological parameters fall within ranges reported for spinnable cellulose dopes in air-gap spinning systems, suggesting strong potential for fibre formation under controlled conditions. These findings establish a robust rheological framework for denim-derived cellulose in NMMO and provide a foundation for future investigations into controlled fibre spinning and process scale-up in sustainable textile recycling. Full article

The textile industry faces significant challenges regarding the need for textile waste recycling. This study investigates the feasibility of alkaline hydrolysis assisted by alcoholic co-solvents, such as ethanol, for recycling polyester/cotton blend textiles. Ethanol-assisted alkaline hydrolysis under mild conditions enabled almost complete depolymerisation of polyester, allowing the recovery of its monomers, terephthalic acid and ethylene glycol, which may be used to produce new polyester fibre. However, the treatment was found to adversely affect the properties of the cotton fibres, resulting in a recycled material of lower quality and functionality than the original material. In particular, a significant change in the structure of the cotton fibre was observed, namely, the transformation of cellulose I into cellulose II, as confirmed by FTIR analysis, along with a decrease in both the degree of polymerization and tensile strength, especially at an ethanol/water ratio of 40/60. Hence, alcohol-assisted alkaline hydrolysis is advisable for the chemical recycling of polyester, but it presents limitations when cotton fibres are also present. Full article

Background/Objectives: Although copper nanoparticles (Cu-NPs) are increasingly explored as food and feed additives, there is still limited evidence on how the commonly consumed dietary fibre matrix modulates their effects on the gut microbiota. This study evaluated whether different dietary fibres (cellulose, pectin, inulin, psyllium) modulate Cu-NP–driven changes in caecal microbiota activity, composition, and bile acid metabolism in rats in a multifactorial design accounting for fibre type, copper dose, and copper form. Methods: Wistar male rats (n = 10 per group, 10 groups) were fed semi-purified diets for 6 weeks. Cu-NPs were provided at 6.5 or 13 mg Cu/kg diet and combined with cellulose (control fibre) or with pectin, inulin, or psyllium. Caecal digesta parameters, microbial enzyme activities, short-chain fatty acids (SCFAs), bile acids, and 16S rRNA sequencing were used to assess microbial diversity. Results: Final body weight did not differ among groups, whereas feed intake decreased most consistently with inulin and psyllium. Inulin and psyllium increased caecal digesta and tissue mass, while pectin increased caecal ammonia. Higher Cu-NPs dose reduced several microbial enzyme activities and lowered major SCFAs across most treatments; pectin most strongly preserved/enhanced glycosidase activities and was associated with increased SCFA levels vs. control, with a 32% rise in acetate, a 47% rise in propionate, and a 61% rise in butyrate. Fibre type dominated bile acid outcomes: psyllium reduced total bile acids by 11.8% vs. control, while inulin increased muricholic acids by 216% vs. control. Microbiota alpha and beta diversity separated primarily by fibre type, with distinct clustering particularly in pectin-fed groups. Across comparisons, Mucispirillum was consistently reduced in fibre-supplemented groups vs. cellulose, alongside recurrent changes in selected genera; functional profiling highlighted shared shifts in carbohydrate, fermentation, transport, and stress-response features under Cu-NPs exposure. Conclusions: The gastrointestinal and microbiota responses to Cu-NPs are strongly fibre-dependent; thus, Cu-NP safety and functionality should be evaluated together with the accompanying dietary fibre matrix, not as a standalone exposure. Implications for humans remain indirect and require confirmation in human-relevant models and clinical settings. Full article

Maize silage can play a key role in policies aimed at stabilising local energy systems, as it constitutes a critical renewable feedstock for European biogas plants. By providing a dense and predictable source of chemical energy, it supports balance and reliability in the agricultural energy sector. To convert this potential into stable energy production, operators require kinetic models that translate routine silage quality indicators into concrete guidance for digester operation and control. Therefore, the aim of this article was to evaluate the batch kinetics of anaerobic digestion (AD) of maize silage and to select an adequate model for describing biochemical methane potential (BMP) profiles and associated energy recovery in the context of start-up, organic loading rate (OLR), hydraulic retention time (HRT) and feedstock preparation. Ten batches of silage (A–J) were examined, covering a realistic range of pH, electrical conductivity (EC), dry and volatile solids, ash, protein–fat–fibre fractions, fibre composition (NDF, ADF and ADL), derived fractions (hemicellulose, cellulose, and residual organic matter (OM)), C/N ratio and macro-/micronutrient profiles, including trace elements relevant to methanogenesis (Ni, Co, Mo, and Se). BMP tests were carried out in batch mode, and the resulting curves were fitted using the modified Gompertz and a first-order kinetic model. Methane yields of approx. 100–120 m³ CH₄/Mg fresh matter (FM) and 336–402 m³ CH₄/Mg volatile solids (VS), with CH₄ contents of 52–57% v/v, were typical for energy-grade maize silage. Kinetic and energetic behaviours were governed mainly by residual OM and hemicellulose (shortening the lag phase and increasing the maximum methane production rate), the ADL/cellulose ratio (controlling the slower hydrolytic tail), EC and Na/Cl/S (extending the lag phase), and C/N together with Ni/Co/Mo/Se (stabilising methanogenesis). The modified Gompertz model reproduced BMP curves with a pronounced lag phase and asymmetry more accurately (lower error and better information criterion values), and its parameters directly support start-up design, OLR ramp-up and energetic performance optimisation in bioenergy reactors. The novelty of this work lies in combining batch BMP tests, comparative kinetic modelling and detailed silage characterisation to establish quantitative links between kinetic parameters and routine maize silage quality indicators that are directly relevant for biogas plant operation and renewable energy production. Full article

This study investigates the combined effect of waste-based metakaolin, cellulose fibres and functional waterproofing additive on the physical, mechanical, and durability-related properties of sustainable concrete. A total of 12 concrete mixtures were produced, varying in cellulose fibre content (0–2%), metakaolin waste replacement levels (up to 10% of binder), and functional waterproofing additive content (1%). The experimental program assessed workability, density, compressive and flexural strength, ultrasonic pulse velocity (UPV) and alkali–silica reaction (ASR) resistance. The presence of metakaolin due to high pozzolanic activity (1451 mg/g) and fine particle size enhance the formation of additional C–S–H phases. The incorporation of cellulose fibres (1–2 mm in length) improved crack-bridging ability and structural integrity, while functional waterproofing additive enhanced water tightness. Results demonstrated that the synergistic use of these materials led to improved mechanical performance (flexural strength varies from 4.87 MPa to 6.81 MPa; compressive strength varies from 24.01 MPa to 32.97 MPa) and enhanced notable ASR resistance (decrease in expansion varies from 0.209% to 0.029%). The findings highlight the potential of combining waste-derived pozzolanic and fibrous materials with functional admixtures to develop environmentally friendly and performance-optimized concrete composites. Full article

Cortical microtubules comprise heterodimeric units of α- and β-tubulin which have been shown to guide the deposition of cellulose microfibrils in plant cell walls where their arrangement is important in determining cell morphology and cell wall properties. Tubulin genes are highly expressed in woody tissues and a functional study has demonstrated a role for a β-tubulin gene family member in affecting the orientation of cellulose microfibrils in wood fibre cells, an important trait in determining the mechanical properties of wood fibres. To further understand the role of tubulins in plant cell trait determination, this study identified and investigated the expression of the α- and β-tubulin gene families in Eucalyptus and then, using transgenesis techniques, investigated the role of specific eucalypt tubulin isoforms in determining secondary cell wall traits of wood fibres in plant stems. This study found that the α- and β-tubulin gene families in Eucalyptus are relatively small compared to other species and show higher expression in woody stem tissue when compared to leaf. Functional studies revealed that cambial cells transformed with α- and β-tubulin overexpression and knockdown vectors, either on their own or in combination, lead to changes in the angle of microfibrils in the secondary cell wall of wood fibre cells with Class I- and Class I-like gene family members explicitly involved. This study demonstrates the importance of tubulins in determining the mechanical properties of wood fibres through a mechanism involving specific tubulin isoform expression during wood fibre formation. Full article

This paper details the development of innovative grading techniques for 3D-printed biopolymer composites that utilize locally sourced, cellulose-based fibre streams to produce architectural-scale components. It examines the design considerations, methodologies, and fabrication strategies that are necessitated by the utilisation of biopolymers for architectural applications, and which underlie key processes of designing for and with variable materials. The presented research interrogates the methodological challenges of formulating new approaches that actively engage architects and designers with the ecological implications of their design choices. It outlines new methods for material grading that enable targeted compositional variation through three interlinked contributions: a gradable recipe, a design-interfaced specification process for grading, and an infrastructure for large-scale 3D printing of biopolymer composites. The paper presents the Rhizaerial demonstrator as an implementation of these contributions. Rhizaerial is a full-scale interior ceiling vault system, whose curved components are printed as a 3D porous lattice structure that creates an interplay of light, visual transparency, and colour, while maintaining structural integrity. We detail the gradable biopolymer composite recipe, and the residual and regenerative material streams it combines. We outline the implicit modelling pipeline, which includes methods for locally specifying lattice structures for 3D printing, as well as assigning continuous grading specifications to print paths. Finally, we describe the fabrication infrastructure and tooling for robotic printing of large-scale graded biopolymer composites. Full article

This research investigates the potential of secondary lavender biomass (Lavandula officinalis) as a raw material for paper production within the context of the circular economy and its practical applications. Lavender stems, a by-product of essential oil extraction, were processed using the nitrate–alkali pulping method. The chemical composition of the raw material was analysed according to TAPPI standards, and the resulting pulp was characterised in terms of its mechanical and physical properties, including tensile strength and air permeability. Lavender stems contained 29.43% cellulose and 24.10% lignin, indicating moderate delignification efficiency under the applied conditions. The pulp yield was 24.2% with a Kappa number of 15.9. Of the prepared sheets, the paper with a weight of 80 g·m⁻² showed the best mechanical properties, with a breaking length of 1.71 km and a tensile strength index of 16.76 N·m·g⁻¹. In addition, lavender-based paper demonstrated measurable repellent activity against Tineola bisselliella, reducing insect presence by 70% compared to control samples, as determined by controlled laboratory exposure tests. This bioactivity is attributed to residual volatile compounds such as linalool and linalyl acetate, originating from lavender biomass. Overall, lavender secondary biomass represents a promising non-wood fibre for the production of biodegradable, functional paper materials that combine structural integrity with natural repellent properties. Full article