Bioresour. Bioprod., Volume 2, Issue 3 (September 2026) – 9 articles

Horsehair generated during seasonal coat shedding represents an underutilized biogenic by-product with potential for textile valorization. In this Communication, we present a first proof-of-concept investigation of the suitability of equine body hair as a raw material for nonwoven production. Hair samples collected during the spring shedding period (March–May) were analyzed for their morphology, fiber dimensions, elemental composition, lipid content, and processing behavior. Pretreatment methods included cleaning and washing, solvent-based degreasing using methyl tert-butyl ether (MTBE), and lipid extraction using supercritical CO₂. Fiber processing trials were conducted using manual and industrial nonwoven formation techniques, followed by mechanical consolidation through needle punching and hydroentanglement. While the results demonstrate that horsehair can be processed into nonwoven structures, pure horsehair webs showed limited fiber cohesion and surface fiber shedding. Blended nonwovens containing Lyocell and sheep wool as well as multilayer structures were therefore produced and showed improved handling and reduced fiber release. In addition, preliminary supercritical CO₂ extraction trials demonstrated the recovery of a substantial lipid-rich fraction, indicating the potential to combine extraction and subsequent fiber utilization within a preliminary cascade valorization strategy. Our study establishes the technical feasibility of this approach while identifying limitations requiring further investigation, particularly quantitative mechanical and functional characterization, optimization of fiber cohesion, chemical characterization of the recovered extract, and environmental and economic assessment. Full article

To realize the high-value valorization of cold-pressed walnut meal, walnut oligopeptides were fabricated via synchronous dual-enzyme hydrolysis combined with activated carbon decolorization and membrane separation purification. We optimized the overall preparation process and systematically characterized the products, including their amino acid profile, in vitro antioxidant capacity, cytoprotective effects against H₂O₂-triggered oxidative injury in PC12 cells, and regulatory activity toward acetylcholinesterase (AChE). The optimal hydrolysis conditions were identified as pH 10.0, total enzyme dosage of 11,000 U/g, a trypsin-to-alkaline protease ratio of 2.1:1, solid–liquid ratio of 1:26, temperature of 51 °C and reaction duration of 4 h, which produced a hydrolysis degree of 33.02%. The optimized decolorization parameters were pH 5.2, activated carbon dosage of 2.3%, treatment at 58 °C for 43 min, with a peptide recovery rate reaching 83.35%. Cold-pressed walnut meal is rich in glutamic acid, arginine and aspartic acid, which lay the molecular foundation for the bioactive properties of the derived oligopeptides. In vitro tests demonstrated that the oligopeptides possessed strong scavenging ability against hydroxyl, DPPH and superoxide anion radicals (clearance rates of 90.18%, 81.72% and 85.80%, respectively), and maintained 73.21% of antioxidant activity after simulated gastrointestinal digestion. Moreover, walnut oligopeptides at 0.8 mg/mL showed no cytotoxicity and afforded a 79.88% protective effect against oxidative damage. The peptides significantly boosted SOD and GSH-Px activities, lowered MDA accumulation, and strongly suppressed AChE activity, performing better than donepezil hydrochloride. This efficient, eco-friendly technique achieves high-value utilization of walnut processing by-products. The obtained oligopeptides possess great potential as natural antioxidants and neuroprotective ingredients for functional food development. Full article

Brazil ranks among the world’s largest agricultural producers, generating substantial agro-industrial residues with significant potential for valorization in biorefinery systems. Comprehensive, updated data on the characterization, availability, and spatial distribution of major crops and their residues are essential for biomass conversion system design but remain lacking in the literature. This study presents a five-part contribution. First, a literature review mapped 534 articles, of which 91 were selected for full-text reading and 37 were retained in the final quantitative synthesis, to assess the generation, location, and availability of Brazil’s main agro-industrial residues and reveal research gaps and trends. Crop production rate was the most frequently reported variable, followed by energy generation potential and residue-to-product ratios; most studies addressed bioenergy applications, while economic and environmental aspects were rarely covered. Second, updated 2023 data estimated from 734.57 to 1168.64 million metric tons of agro-industrial residues generated in Brazil. Third, the work reviewed biomass processing routes, covering upstream (pretreatment and conversion) and downstream stages. Fourth, product yield data were compiled for the residues of seven of the eight assessed crops, standardized per 100 g of dry biomass, enabling cross-feedstock and cross-route comparisons not previously available in a consolidated dataset. Fifth, the study maps Brazilian bioenergy policy instruments against the governance dimensions required for coordinated biorefinery deployment, identifying fragmentation across ministries and priority recommendations for policy action. Although grounded in the Brazilian context, the methodological framework and yield dataset are transferable to other biomass-producing regions, supporting residue-based biorefinery design at different scales. Full article

The effects of pyrolysis temperature (400–500 °C) and time (30–90 min) on the yield and chemical and physical properties of biochar produced from almond and pistachio shells were studied using a fixed-bed pyrolyzer. Thermogravimetric analysis (TGA) was employed to characterize the kinetics of thermal degradation of the shells. This study compared the thermal behavior observed by TGA with biochar yields obtained from a fixed-bed pyrolyzer, providing insight into the agreement between laboratory-scale thermogravimetric measurements and fixed-bed pyrolysis performance. Fourier transform infrared spectroscopy (FTIR) was performed for each type of biochar. Results showed higher biochar yields from almond shells (35.0–41.3% dry basis) than from pistachio shells (26.8–36.7% dry basis). Shell type, pyrolysis temperature, pyrolysis time, and their interactions had significant effects on biochar yield. The Derivative Thermogravimetric (DTG) profiles showed distinct thermal decomposition patterns for almond and pistachio shells. Almond shells exhibited broader decomposition regions, while pistachio shells showed more distinct decomposition stages. FTIR analysis of both shell biochars indicated reduced O–H and oxygen-containing groups with increasing pyrolysis temperature and residence time, suggesting greater carbonization, aromatic enrichment, and formation of carbonaceous compounds. Greater biochar yields were obtained from the fixed-bed pyrolyzer than from TGA. A first-order kinetics model adequately described the thermal decomposition of both shell types. Apparent activation energies were 41.83–44.99 kJ mole⁻¹ for almond shells and 58.19–63.58 kJ mole⁻¹ for pistachio shells. Model validation showed a good agreement between the experimental and predicted conversion values. The results provide a basis for evaluating the potential of TGA-derived thermal behavior to inform biochar production conditions in fixed-bed pyrolysis. Full article

Horse manure is an abundant lignocellulosic feedstock with potential for circular biorefineries to diversify and upgrade the methane value chain. However, integrated fractionation strategies enabling the simultaneous valorization of both polysaccharides and lignin remain poorly explored. Here, we developed the Coffionic strategy, a closed-loop, green iono-organosolv fractionation combining, in a two-step, one-batch approach, the eco-acceptable ionic liquid 1-ethyl-3-methylimidazolium acetate and the food-grade solvent 2-methyltetrahydrofuran-3-one, with full solvent recovery and recycling. This strategy selectively recovered 70% w/w of the lignin from horse manure, yielding a Coffionic lignin fraction with a purity of 78% w/w and less than 2.5% w/w of residual sugars. The resulting polysaccharide-rich fraction showed enhanced enzymatic digestibility, achieving >99% cellulose conversion and increasing the biochemical methane potential by 17% compared with untreated horse manure. Coffionic lignin was further upgraded by enzymatic transesterification using immobilized Novozym435^® in the same food-grade solvent employed for fractionation, yielding lignin esters compatible with PLA. Esterified lignin–PLA films reached a total surface energy significantly higher than neat PLA and unmodified lignin–PLA films. Overall, the Coffionic strategy provides an integrated and low-waste biorefinery route enabling the simultaneous production of biomethane and high-value lignin-based materials from horse manure. Full article

Percolation-based dry anaerobic digestion (AD) is an attractive technology for treating high-solids food waste (FW) because it requires minimal water addition and eliminates the need for mechanical mixing. However, its methane production is often limited by slow hydrolysis and inefficient conversion of soluble intermediates. To overcome these limitations, this study developed a bioelectrochemical leach-bed reactor (BLBR) by integrating a microbial electrolysis cell with a percolation-based dry AD system to enhance methane production kinetics. Two 10-L reactors were operated in 10-day batch mode: an open-circuit control reactor and a bioelectrochemical reactor operated with applied voltages ranging from 0.3 to 1.2 V. Moderate voltage application significantly enhanced methane production, with the highest cumulative methane yield reaching 293 mL CH₄/gVS_added at 0.9 V, representing a 47% increase over the control (199 mL CH₄/gVS_added), while volatile solids removal remained comparable between treatments. Voltage-assisted operation promoted a rapid increase in soluble chemical oxygen demand (SCOD), followed by faster consumption than in the control. Similarly, acetate and propionate accumulated and were depleted earlier, indicating accelerated conversion of soluble intermediates. A transient butyrate concentration of 8.8 g COD/L was observed at 0.9 V, suggesting enhanced fermentative activity under moderate bioelectrochemical stimulation. Full article

The transition from a linear to a circular economic model is critical for the sustainability of the Amazonian bioeconomy. Although Amazon nuts (internationally recognized as Brazil nuts, Bertholletia excelsa) represent a major natural bioresource, their production chain faces structural challenges, particularly concerning the underutilization and disposal of agro-industrial residues. This narrative review analyzes the Amazon nut market, processing technologies, and supply chain, with a specific focus on biomass valorization. By evaluating the recent literature across major scientific databases, this study maps the technological readiness and feasibility of integrating a circular economy model. We critically examine alternative technologies for transforming specific residues, particularly the woody fruit pods, hard seed shells, and oil press cakes, into value-added bioproducts. Key valorization routes discussed include protein concentrates and amino acid supplements from the press cake, cellulose nanocrystals and organic panels from the hard seed shell, biosolvents, and bioenergy/biochar generation via pyrolysis. The review concludes that while the current industry remains strictly focused on kernel commerce, transitioning toward a circular model appears technically promising, but its economic feasibility remains unconfirmed for most valorization pathways. However, successful industrial implementation requires overcoming logistical supply chain barriers and advancing the technology readiness levels of these valorization pathways. Full article

Agro-industrial residues such as prickly pear peel represent an underutilized source of bioactive compounds. However, comparative evidence on green extraction versus biotransformation strategies remains limited. This study evaluated solid-state fermentation (SSF), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE) for tannin recovery from Opuntia ficus-indica peel. SSF using Aspergillus niger significantly enhanced condensed tannins (>50 mg/g) and hydrolyzable tannins (~7 mg/g), outperforming UAE and MAE. This improvement was associated with fungal-mediated cell wall degradation and metabolic transformation. SSF extracts also showed superior antioxidant activity (DPPH, ABTS, and FRAP) and exclusive antimicrobial activity against Escherichia coli (4.5 mm inhibition zone). HPLC analysis revealed increased phenolic diversity, with rhamnetin as the predominant metabolite. These findings demonstrate that SSF is not only an extraction method but also a biotransformation strategy that enhances both the yield and functionality of phenolic compounds. This approach supports the sustainable valorization of agro-industrial residues within a circular bioeconomy framework. Full article

Pinus pinaster Ait. forests have potential for resin tapping, a forestry activity that complements timber production and may increase the profitability of maritime pine stands. However, the viability of this co-production remains uncertain due to the potential effects of resin tapping on wood characteristics. The present study aimed to investigate the effects of resin tapping on the wood characteristics of maritime pine, in order to infer possible changes in wood quality, its utilisation, and, consequently, its value. The study was based on samples collected in Tresminas from resin-tapped trees (37.2 ± 6.0 years old and mean height of 15.8 ± 1.4 m) subjected to the traditional Portuguese resin tapping method for four consecutive years, and from non-resin-tapped trees (37.5 ± 8.9 years old and mean height of 14.1 ± 2.2 m). Samples were collected from different positions along the stem of resin-tapped trees (incision side, opposite side, and 50 cm above the last tapping incision) and compared with samples obtained from non-resin-tapped trees. Wood density, modulus of elasticity (MOE), modulus of rupture (MOR), extractives content, growth ring width and the number and area of resin ducts were evaluated. The effects of resin tapping on wood properties were assessed by comparing resin-tapped and non-resin-tapped trees, as well as different sampling positions within resin-tapped trees, using linear mixed-effects models. Mean comparisons were performed using Tukey’s test at a 95% significance level. No significant effects of resin tapping were observed on MOE or MOR between resin-tapped and non-resin-tapped trees. Wood from the incision side showed higher density (0.596 g·cm⁻³) and higher extractives content (7.49%). Resin-tapped trees produced a greater number of resin ducts after tapping; however, their area did not change. No significant differences were found in growth ring width between resin-tapped (1.75 mm) and non-resin-tapped trees (1.80 mm), although resin-tapped trees presented slightly narrower rings on average. Resin tapping in P. pinaster did not promote relevant changes in wood properties that would compromise its mechanical and physical performance. Although some alterations were detected, these were predominantly localised and restricted to the region adjacent to the tapping incision. Full article