Search Results (4,583)

The efficiency of anaerobic digestion (AD) of lignocellulosic biomass is strongly determined by biomass yield, chemical composition, and bioavailability, all of which undergo substantial seasonal variation. However, integrated analyses linking these factors with AD performance, process kinetics, and energy-economic efficiency remain limited. This study aimed to evaluate the effect of seasonal variability in the chemical composition of Helianthus annuus biomass on AD efficiency from a technological and economic perspective. The novelty of this study lies in integrating seasonal changes in biomass composition with AD kinetics, CH₄ productivity per hectare, and CHP techno-economic performance to identify the optimal harvest window for Helianthus annuus. The experiments were conducted using biomass harvested from June to December. The results showed significant (p < 0.05) variability in biomass properties, including a progressive increase in lignocellulosic fractions over the growing season, with neutral detergent fiber (NDF) increasing from 30.58 ± 1.8 to 66.58 ± 3.1% TS and acid detergent lignin (ADL) from 5.13 ± 0.5 to 10.35 ± 0.9% TS, accompanied by a decline in substrate bioavailability. The maximum CH₄ yield of 258 ± 13 mL/g VS was obtained in August, with a process rate of 29.0 ± 3.4 mL/g VS·d and the highest utilization of methane potential, reaching 62.5 ± 3.8% (BMP_CH4/TBMP). Correlation and regression analyses indicated that ADL and NDF were the strongest empirical predictors of AD performance within the analyzed dataset, showing a negative association with both CH₄ production yield and kinetics (R² up to 0.86), whereas reducing sugars had a stimulatory effect. Multiple regression models showed high predictive performance, with R² = 0.889 for BMP_CH4. The highest energy and economic efficiency was achieved in summer. In August, CH₄ production reached 3214 ± 596 m³/ha, corresponding to 11.2 ± 2.1 MWh/ha of electricity and a net result of 1559 ± 417 EUR/ha. Increased lignification in the later part of the season led to reduced process efficiency and a deterioration of the economic balance. From a practical perspective, these results demonstrate that harvest scheduling should be based on the trade-off between biomass quantity and biodegradability rather than on biomass yield alone. Full article

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

This study investigated the influence of carrot cryopowder, obtained by cryogenic grinding, on the rheological, physicochemical, and structural characteristics of a structured curd product. The experiment was conducted using a three-factor Box–Behnken design, varying the mass fraction of curd (70–90%), carrot cryopowder content (2–6%), and fat content in cream (7–33%). Viscosity values ranged from 914 to 2810 mPa·s, with the highest value of (2810 mPa·s) recorded in experimental sample No. 5. The best overall characteristics were observed in this sample, which showed a β-carotene content of 2.76 ± 0.03 µg/g, while the concentrations of vitamins B1, B2, B3, B5, B6, and folic acid were 20–31% higher compared to the control sample. The regression model (R² = 0.9164) identified the optimal formulation: 89.6% curd, 5.4% carrot cryopowder, and 31.3% fat in cream. Storage stability studies conducted over 28 days at 4 ± 1 °C demonstrated additional practical advantages. The addition of carrot cryopowder significantly reduced syneresis to 12.4 ± 1.1% on day 28 (compared to 28.7 ± 2.3% in the control), improved microbiological stability, and maintained acceptable sensory properties with an overall acceptability score of 6.8 ± 0.6 points after 28 days. FTIR analysis confirmed that the carrot cryopowder was not merely mechanically dispersed within the matrix but actively participated in the formation of new intermolecular interactions, leading to the modification of the product’s chemical structure. The obtained results showed that the incorporation of carrot cryopowder not only increased the nutritional and functional value of the curd product but also enhanced its structural stability and potential shelf life without negatively affecting the main technological indicators. Full article

The Azorean livestock system depends strongly on pasture-based feeding, making regional agriculture sensitive to global warming. This study assessed the effects of experimental warming on forage productivity, forage quality, and soil fertility in three pastures along an altitudinal gradient over two years (2020–2021). Open-top chambers were used to create warmer conditions, and soil and forage samples were analysed for chemical and mineral composition. Warming increased net forage productivity by 30% and 70% in the lower-altitude pasture in 2020 and 2021, respectively, and by 56% in the intermediate-altitude pasture in 2021. Responses at the highest altitude were weak or not significant. Effects on forage quality were seasonal. In winter and early spring, warming increased crude protein by 14–45% and ash by 4–13% in the lower- and intermediate-altitude pastures. Later in the season, warming was associated with higher fibre fractions, especially in the intermediate-altitude pasture, indicating faster plant maturation. Soil factors significantly structured forage quality, with phosphorus as the main driver. This study contributes to understanding how climate change may affect the sustainability of pasture-based livestock systems in island environments, supporting the development of adaptive management strategies to safeguard productivity, soil fertility, and ecosystem resilience. Full article

To identify quality markers (Q-markers) for daodi authenticity evaluation of Lycium barbarum L., a comprehensive strategy integrating appearance trait analysis, multi-component quantification, and chemometrics was developed. Forty-five sample batches were collected from four major producing areas in China, namely Ningxia (NX), Gansu (GS), Qinghai (QH), and Inner Mongolia (NM). Appearance traits (50-fruit weight, moisture, and color) and the contents of polysaccharide, total sugar, betaine, zeaxanthin dipalmitate, and 27 small-molecule compounds, including flavonoids and phenolics, were determined using UV–vis spectrophotometry, HPLC-CAD, and UPLC-MS/MS. Pearson correlation analysis revealed a significant negative association between polysaccharide and total sugar (r = −0.344, p < 0.05), suggesting a possible allocation shift between the two carbohydrate fractions, while zeaxanthin dipalmitate strongly correlated with redness (r = 0.609, p < 0.01). Principal component analysis identified total sugar, polysaccharide, scopoletin, and scopolin as key discriminatory variables. AHP-CRITIC combined weighting highlighted polysaccharide (weight 0.195) and zeaxanthin dipalmitate (weight 0.157) as candidate core Q-markers. Top-ranked comprehensive scores predominantly belonged to samples from NX and GS, chemically supporting the traditional daodi authenticity. This dual-dimensional “efficacy–trait” framework provides a robust, traceable basis for origin authentication and quality standard improvement of L. barbarum. Full article

Passion fruit (Passiflora edulis) processing generates by-products rich in bioactive secondary metabolites; however, comparative characterization across fruit fractions remains limited. This study evaluated pulp (PPE), pulp-seed (PSC), and seed (PSE) extracts for extraction yield, metabolite composition, antioxidant and anti-aging activities, and collagen-stimulatory activity in human skin fibroblasts. Extraction yields followed the order PPE > PSE > PSC. Untargeted LC–QTOF/MS profiling revealed distinct phytochemical patterns, with piceatannol enriched in PSE and trans-ferulic acid broadly abundant across all fractions. PSE showed the strongest antioxidant activity in DPPH and FRAP assays, and both PSE and PSC inhibited collagenase and hyaluronidase, while PPE showed negligible activity. All extracts were non-cytotoxic up to 0.1 mg/mL. At this concentration, PSC enhanced type I collagen production by 8.07 ± 2.24%, significantly exceeding PSE (2.26 ± 1.33%), while piceatannol stimulated collagen synthesis by 11.34 ± 1.50%, comparable to L-ascorbic acid (13.90 ± 1.16%). Molecular docking suggested that piceatannol and trans-ferulic acid may contribute to the observed anti-aging effects by interacting favorably with collagenase and hyaluronidase. These findings demonstrate that passion fruit by-product fractions exhibit complementary bioactivity profiles, with PSE favoring antioxidant and enzyme inhibitory effects and PSC enhancing collagen biosynthesis, as natural anti-aging applications. Full article

Gold-mine tailings have attracted increasing interest as alternative constituents in cement-based materials, yet their use in structural concrete remains limited by the lack of multivariable approaches capable of capturing the interaction between tailing fractions with different functional roles. In this study, a tailing-derived fine aggregate and a fine tailing sludge from the Cisneros Project (Santo Domingo, Antioquia, Colombia) were jointly incorporated into structural concrete and evaluated through a response surface methodology based on a central composite design. The tailings were characterized by physical, chemical, mineralogical, and morphological analyses, while concrete mixtures proportioned according to ACI 211 were assessed in terms of 28-day compressive strength. The statistical model revealed a significant quadratic response and a strong interaction between both incorporation variables. The most favorable strength region, based solely on 28-day compressive strength, was identified at sludge contents below 20% and tailing aggregate replacement below 90%, with the latter interpreted as a preliminary mechanical threshold rather than as a practical recommendation for field application. Higher incorporation levels led to strength losses associated with the increasing fineness of the system and greater water demand. This study demonstrates that the performance of tailing-modified structural concrete depends on the coordinated dosage of fractions with distinct roles and provides preliminary mechanical incorporation limits based solely on 28-day compressive strength. Since durability and environmental safety tests, including heavy metal/cyanide leaching, permeability, shrinkage, and chemical resistance, were not conducted, these limits should not be interpreted as definitive recommendations for long-term structural application. Full article

The aim of this study was to critically assess the usefulness of pollution indicators in monitoring riverside soils (fluvisols) for heavy metal content. A novel methodological approach was used, comparing areas located inside and outside flood embankments, which allowed for a precise determination of the impact of fluvial and anthropogenic processes on heavy metal accumulation. The experimental logic validated the usefulness of four indicators: the Individual Pollutant Index (PI), the Background Enrichment Factor (PIN), the Potential Ecological Risk (RI), and the Pollution Load Index (PLI). Comparative analysis revealed that soils within the embankment zone have higher metal concentrations, resulting from the continuous deposition of alluvial material, which often contains industrial and municipal pollutants. The vertical distribution of pollutants in fluvisols was shown to be closely related to sediment dynamics and soil properties (clay fraction, organic matter, redox conditions). Validation of the indicators revealed their varying sensitivity. The study revealed the limitations of the PLI, which, due to its summary nature, did not account for significant variability in contamination within the soil profile. Consequently, the PI, PIN, and RI indices were shown to be the most effective tools in assessing the actual degree of soil contamination by fluvisols in the middle Oder Valley. The study results emphasise the need for the selective selection of indicators in environmental monitoring. This comparative approach provides a reliable method for assessing the effectiveness of floodplain management strategies under exposure to chemical pressure. Full article

Bamboo shoot dietary fiber (BSDF) is dominated by an insoluble fraction, which severely restricts its physicochemical performance and food application. In this study, the soluble dietary fiber (SDF) content of bamboo shoots was enhanced using three enzyme fermentation sequences: enzymatic hydrolysis followed by fermentation (EH), fermentation followed by enzymatic hydrolysis (F-EH), and integrated enzymatic hydrolysis and fermentation (IEHF). EH-F treatment resulted in the highest SDF content (17.27%). Variations in pH, biomass, enzyme activity, and short-chain fatty acids were assessed to understand the differences in the modification efficiency among the treatment sequences. Fourier transform infrared (FTIR) spectroscopy indicated that sequential enzymatic and fermentation treatments altered the chemical structure of bamboo shoot powder, consistent with the conversion of insoluble to soluble fractions. SDF from the EH-F treatment exhibited superior water-holding capacity (6.71 g/g), oil affinity (6.42 g/g), and DPPH radical scavenging rate (65.69% at 1.2 mg/mL). Moreover, SDF from the EH-F treatment achieved an 87.82% carbohydrate residue retention rate during simulated gastrointestinal digestion. These enhanced properties were associated with improved hydration properties resulting from the sequential tailoring process. This preliminary study explored the effects of different enzyme fermentation sequences on BSDF modification, providing a reference for the utilization of BSDF. Full article

Metals like Li, Sn, W, Nb and Ta accumulate mostly during the magmatic–hydrothermal transition and subsequent hydrothermal alteration of highly fractionated granites, especially greisenization. Evaluation of about 450 bulk-rock analyses, 1500 LA-ICP-MS analyses of quartz and 1600 EPMA and LA-ICP-MS analyses of mica from parental granites and related greisens and quartz–mica veins from four typical areas of European Variscan granite plutons with greisen mineralization (Beauvoir, France; Panasqueira, Portugal; and Cínovec and Nejdek, Erzgebirge, Czech Republic) illustrate diversity in initial magma composition (S- vs. A-types), in style of greisenization (pervasive greisenization in granite cupolas vs. vein-like greisen strings along joints), and in chemical evolution of quartz and micas during magmatic–hydrothermal transition. The contents of all monitored elements in quartz and mica from greisen and veins are of very high variability, with principal differences among studied localities. Generally, very low contents of Al (<100 ppm), Ti (<1 ppm) and Li (<10 ppm) or, on the contrary, extremely high contents of Al (>1000 ppm) or Li (>100 ppm) in quartz may indicate its hydrothermal origin. Contents of Sn, W, Nb, and Ta in micas tend to become depleted during greisenization, this trend is more pronounced in Nb and Ta than in Sn and W. Transition from magmatic to hydrothermal crystallization leads to an increase in the Ta/Nb values in mica: from 0.20 to 0.24 in S-type magmatic systems, and from 0.13 to 0.34 at Cínovec as a representative of A-type granites. Whether granite belongs to the S- or A-type is not essential for the development of greisenization. Full article

Nitrogen (N) fertilization is a fundamental agronomic practice that governs crop productivity, yet its effects on the molecular composition and chemical stability of soil organic carbon (SOC) remain poorly understood, especially in cereal–legume intercropping systems. Traditional studies have focused on total SOC stocks rather than molecular-level changes, and the mechanistic pathway linking N addition to SOC functional group transformation remains unclear. This study addressed these critical gaps by investigating how graded N addition (0, 180, 270, and 360 kg N ha⁻¹) reshapes SOC chemistry in a subtropical soybean–maize intercropping system. Soil physicochemical properties, inorganic N pools, N-transformation enzyme activities (urease, nitrate reductase, and glutaminase), microbial biomass indices, labile organic carbon fractions (particulate, mineral-associated, and dissolved organic carbon), and SOC functional groups characterized by Fourier transform infrared (FTIR) spectroscopy were quantified across a two-year field experiment (2024–2025). Results showed that increasing N rates significantly elevated nitrate nitrogen (NO₃⁻-N) accumulation while depressing soil pH. Nitrogen-transformation enzymes, especially nitrate reductase and glutaminase, responded strongly and positively to the N gradient. Microbial biomass carbon (MBC) and nitrogen (MBN) increased with moderate N input but exhibited saturation or decline at 360 kg N ha⁻¹, accompanied by reduced microbial carbon use efficiency (CUE) and a lower MBC/MBN ratio. Among labile carbon fractions, dissolved organic carbon (DOC) was the most responsive pool, increasing markedly with N addition and correlating strongly with NO₃⁻-N. FTIR analysis revealed that N addition shifted SOC functional group composition toward chemically recalcitrant structures: the relative abundances of aromatic C=C and carbonyl C=O groups increased significantly, whereas labile C–O groups declined. Random forest modelling identified C=C, NO₃⁻-N, and DOC as the three most influential predictors of SOC chemical composition. Structural equation modelling (SEM) demonstrated a sequential mechanistic pathway: N fertilization increased NO₃⁻-N, which stimulated glutaminase activity and enhanced DOC, ultimately promoting C=C/C=O stabilization and explaining 91.3% of the variance in SOC aromaticity. These findings reveal that N addition does not merely augment SOC quantity but fundamentally transforms its molecular architecture toward greater chemical stability through a nitrate-mediated, enzyme–labile carbon coupling mechanism. This study provides a novel spectroscopic–mechanistic framework for understanding carbon–nitrogen interactions in intercropping agroecosystems and informs precision N management strategies aimed at simultaneous crop production and long-term soil carbon sequestration. Full article

This study evaluated the effectiveness of maleic anhydride polypropylene (MAPP) in improving the mechanical performance and interfacial adhesion of lignocellulosic fiber-reinforced polypropylene (PP) composites. Based on Scanning Electron Microscopy (SEM) investigations, the relationship between fiber fraction, MAPP content, mechanical characteristics, and fracture morphology was the main focus. The test results showed that the stiffness and tensile strength of the composites increased with the addition of MAPP. The esterification reaction between the anhydride groups of MAPP and the hydroxyl groups of the fibers strengthened the interphase covalent bond, with the 46:50:4 composition producing the highest elastic modulus of 79.67 MPa and maximum tensile stress of 11.01 MPa. The dense interphase zone, few gaps, and no dominant fiber tension were all confirmed by SEM morphology, and also indicated effective stress transfer from the PP matrix to the fibers. However, the toughness of the material decreased significantly with increasing stiffness. Due to strong plastic deformation in the PP matrix that is not tightly attached to the fibers, the composition without MAPP (30:70:0) shows high impact energy and breaking strain, reaching 25.39 kJ/m² and 121.26%, respectively. The increase in chemical bonding at 4% MAPP content limits the mobility of the polymer chains, making it more brittle. In addition, even though MAPP is still present in the system, increasing the fiber fraction above 60% causes agglomeration, decreased homogeneity, and increased voids due to limited matrix wetting, ultimately deteriorating the mechanical properties. Tensile stress and elastic modulus have a very strong positive correlation (R² = 0.93), while impact energy and strain have a good correlation (R² = 0.89). The results overall showed that the ideal MAPP dosage is in the range of 4% before interface saturation occurs and confirmed that MAPP efficiency is determined by the balance between fiber composition, MAPP quantity, and dispersion homogeneity. Full article

Bamboo as a functional gradient biomaterial refers to the understanding of bamboo culms as naturally hierarchical, anisotropic, and radially heterogeneous lignocellulosic structures whose mechanical, chemical, and conversion properties vary across the wall thickness. Gradients in fiber volume fraction, vascular bundle distribution, moisture, density, mineral content, and silica deposition influence stiffness, strength, durability, permeability, surface hardness, and thermal conversion behavior. This entry treats bamboo not only as a renewable plant resource, but also as a biologically organized material platform for structural components, engineered composites, and carbon-rich products such as biochar and activated carbon. A gradient-based view helps connect bamboo characterization with layer-aware processing, feedstock classification, and circular bio-based material design. Full article

Ornamental fountains in the Alhambra and Generalife (Granada, Spain) constitute complex socio-ecological systems where water, stone, and biological communities interact, making them highly vulnerable to biodeterioration caused by phototrophic microorganisms such as cyanobacteria, green algae, and diatoms. Conventional chemical biocides, although widely applied, present significant drawbacks including toxicity, material degradation, ecological imbalance, and limited long-term effectiveness. In this context, this study evaluated the potential of algicidal bacteria as a sustainable alternative for controlling phototrophic growth in heritage environments. Water samples from eight ornamental fountains were analyzed using 16S ribosomal RNA (16S rRNA) gene sequencing to characterize bacterial communities and identify taxa previously reported with algicidal activity. Statistical analyses were conducted to assess relationships between microbial community structure and biofilm development. In parallel, functional screening assays using filtered fountain waters against Chlorella vulgaris were performed to evaluate intrinsic inhibitory capacity. The most active sample was selected for bacterial isolation and further validation through co-culture assays, cell density measurements, and pulse-amplitude-modulated (PAM) fluorometry. A total of 18 genera with reported algicidal capacity were detected, representing a substantial fraction of the microbiome across all samples. However, no significant association was found between these taxonomic metrics and biofilm development, highlighting a decoupling between taxonomic composition and functional activity. The most active isolate, identified as Stenotrophomonas maltophilia strain LIG25, caused a rapid decline in photosynthetic efficiency and achieved more than 98% inhibition of algal growth. These findings demonstrate that ornamental fountain microbiomes represent a reservoir of native biocontrol agents and support the development of eco-friendly strategies for cultural heritage conservation. Full article

In recent years, cruor from slaughterhouse blood has garnered growing interest as a potential source of antimicrobial peptides obtained through enzymatic hydrolysis. In addition, electrodialysis with ultrafiltration membrane (EDUF) represents a strategy for valorizing peptide-rich hydrolysates, enabling the selective separation and concentration of antimicrobial peptides, according to their size and charge. Hence, this study evaluated the potential of EDUF to fractionate, for the first time, calf cruor hydrolysate and explore its use as a novel source of antimicrobial peptides. The resulting peptide fractions were characterized to investigate the selectivity of peptide migration in relation to peptide physico-chemical characteristics and membrane properties and to finally assess their antimicrobial activity. High migration rates of 12.75 ± 2.17 g/m²h and 8.94 ± 0.38 g/m²h were observed for the cationic (P⁺) and anionic (P⁻) recovery fractions, respectively. These results suggested that peptide migration from calf cruor hydrolysate to both recovery fractions during EDUF was influenced by the combined effects of molecular weight, net charge, hydrophobicity, specific amino acid residues (L, Y), and peptide–membrane interactions. Furthermore, the initial and final hydrolysates as well as P⁺ fractions exhibited antifungal activities against Paecilomyces spp. and Rhodotorula mucilaginosa with minimum inhibitory concentrations (MIC) ranging from 0.312 to 0.615 mg/mL and minimum fungicidal concentrations (MFCs) ranging from 0.312 to 1.250 mg/mL. In contrast, the P⁻ fraction did not exhibit antifungal activity, but a slight anti-Listeria activity was detected, with a MIC of 10 mg/mL. These findings highlight the potential of upcycling calf blood into functional antifungal and antibacterial agents, supporting a circular economy approach and transforming waste streams into value-added ingredients that enhance food preservation. Full article