Search Results (277)

Soil degradation, declining fertility, and rising greenhouse gas emissions highlight the urgent need for sustainable soil management strategies. Among them, biochar has gained recognition as a multifunctional material capable of enhancing soil fertility, sequestering carbon, and valorizing biomass residues within circular economy frameworks. This review synthesizes evidence from 186 peer-reviewed studies to evaluate how feedstock diversity, pyrolysis temperature, and elemental composition shape the agronomic and environmental performance of biochar. Crop residues dominated the literature (17.6%), while wood, manures, sewage sludge, and industrial by-products provided more targeted functionalities. Pyrolysis temperature emerged as the primary performance driver: 300–400 °C biochars improved pH, cation exchange capacity (CEC), water retention, and crop yield, whereas 450–550 °C biochars favored stability, nutrient concentration, and long-term carbon sequestration. Elemental composition averaged 60.7 wt.% C, 2.1 wt.% N, and 27.5 wt.% O, underscoring trade-offs between nutrient supply and structural persistence. Greenhouse gas (GHG) outcomes were context-dependent, with consistent Nitrous Oxide (N₂O) reductions in loam and clay soils but variable CH₄ responses in paddy systems. An emerging trend, present in 10.6% of studies, is the integration of artificial intelligence (AI) to improve predictive accuracy, adsorption modeling, and life-cycle assessment. Collectively, the evidence confirms that biochar cannot be universally optimized but must be tailored to specific objectives, ranging from soil fertility enhancement to climate mitigation. Full article

Aqueous phase reforming has been posed as a promising technology for renewable hydrogen production in the framework of the transition to a sustainable energy economy. Since the use of chemical compounds as process feedstock has proven to be one of the major constraints to its potential scalability, several cost-free residual biomasses have been investigated as alternative substrates. This also allows for the recovery of residues, offsetting the significant costs of waste management through conventional treatment. In recent years, different wastes from the food processing industry such as brewery, fish canning, dairy industries, fruit juice extraction, and corn production wastewaters, have taken the attention of scientific community due to their composition, favorable to this process, and its high-water content. However, few and heterogeneous results can be found within the literature, suggesting that the research into this application is now at a stage of development which will require further investigation. Therefore, this work is focused on compiling and discussing the reported studies, aiming to present a critical reflection on the potential of aqueous phase reforming as a means for the valorization of this kind of residue. Full article

The mushroom industry generates a substantial amount of residues each year, encompassing materials such as processing residues and spent substrates. Much of this biomass is discarded, despite its richness in valuable compounds. Mushroom residues contain bioactive substances including β-glucans, phenolic compounds, proteins, and dietary fiber, all of which are well known for their antioxidant and antimicrobial properties. While fruit and vegetable residues have been extensively explored as raw materials for eco-friendly packaging, mushroom-derived residues remain a largely underutilized resource. Recent studies have highlighted their potential as a renewable source of functional ingredients for sustainable food packaging. By applying green extraction technologies such as ultrasound- or microwave-assisted methods, researchers can recover stable bioactive compounds and incorporate them into biodegradable polymers. Early results are promising: packaging films enriched with mushroom residue extracts demonstrate improved mechanical strength, enhanced barrier properties, and added bioactivity. This strategy aligns with the principles of the Circular Economy, simultaneously reducing environmental impact and adding value to materials that were previously discarded. Although further optimization is needed, particularly regarding extraction efficiency, compound stability, and scalability, the valorization of mushroom residues represents a promising pathway toward the next generation of sustainable, eco-friendly packaging materials. Full article

Plastic-based materials dominate the packaging industry. However, their non-biodegradability has increased the need for sustainable alternatives. Biopolymers, mainly lignocellulose from agricultural residues, offer renewable, eco-friendly options in this context. This study reports the development of lignocellulosic films from alfalfa (Medicago sativa) through green valorization of its biomass. Alfalfa lignocellulosic extract (ALE) was extracted using 50% NaOH, solubilized in 68% ZnCl₂, crosslinked with CaCl₂, and plasticized with sorbitol. The concentrations of ALE, CaCl₂, and sorbitol were optimized using the Box–Behnken Design, focusing on increasing tensile strength (TS), elongation at break (EB), and reducing water vapor permeability (WVP) of the films. The optimized film formulation (0.5 g ALE, 453.8 mM CaCl₂, 1.5% sorbitol) showed a TS of 11.2 ± 0.7 MPa, EB of 5.8 ± 0.9%, and WVP of 1.2 ± 0.2 × 10⁻¹⁰ g m⁻¹ s⁻¹ Pa⁻¹. The film effectively blocked UV–Vis–IR light and exhibited notable antioxidant activity, making it suitable for packaging light-sensitive and oxidation-sensitive foods. Additionally, it achieved over 90% biodegradation within 29 days under 24% soil moisture. These findings demonstrate a sustainable approach to upcycling agricultural residues into functional products, offering a practical alternative to traditional plastics and supporting a circular bioeconomy, while adding value for alfalfa producers. Full article

Lignocellulosic biomass—the non-edible fraction of plants composed of cellulose, hemicellulose, and lignin—is the most abundant renewable carbon resource and a key lever for shifting from fossil to bio-based production. Agro-industrial residues (straws, cobs, shells, bagasse, brewery spent grains, etc.) offer low-cost, widely available feedstocks but are difficult to process because their polymers form a tightly integrated, three-dimensional matrix. Within this matrix, lignin provides rigidity, hydrophobicity, and defense, yet its heterogeneity and recalcitrance impede saccharification and upgrading. Today, most technical lignin from pulping and emerging biorefineries is burned for energy, despite growing opportunities to valorize it directly as a macromolecule (e.g., adhesives, foams, carbon precursors, UV/antioxidant additives) or via depolymerization to low-molecular-weight aromatics for fuels and chemicals. Extraction route and severity strongly condition lignin structure linkages (coumaryl-, coniferyl-, and sinapyl-alcohol ratios), determining reactivity, solubility, and product selectivity. Advances in selective fractionation, reductive/oxidative catalysis, and hybrid chemo-biological routes are improving yields while limiting condensation. Remaining barriers include feedstock variability, solvent and catalyst recovery, hydrogen and energy intensity, and market adoption (e.g., low-emission adhesives). Elevating lignin from fuel to product within integrated biorefineries can unlock significant environmental and economic benefits. Full article

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

The recovery of timber residues from abandoned underground coal mines presents a unique opportunity to expand the raw material base for wood-based composites, aligning with the principles of cascade utilization. Large amounts of structural wood, embedded for decades under anaerobic and humid mining conditions, remain remarkably well-preserved and can be valorized as a secondary feedstock. The aim of this work was to investigate and evaluate the feasibility of incorporating recovered mining timber into the production of medium-density fiberboards (MDFs). Six types of laboratory panels were produced, containing different ratios of recovered and virgin pine fibers (0–100%), bonded with melamine–urea–formaldehyde resin and hot-pressed at 180 °C. Comprehensive testing of physical and mechanical properties demonstrated that panels with up to 40% recovered fibers fully complied with European standards for general-purpose boards, while up to 60% substitution was acceptable with respect to internal bond strength. At higher substitution levels, however, dimensional stability and strength were significantly reduced. These findings highlight the potential of mine timber recovery as a viable raw material pathway for MDF manufacturing, extending the service life of wood resources and reducing pressure on primary forests. The study emphasizes the role of recovered biomass in advancing circular bioeconomy objectives and resource efficiency in the wood-based panel sector. Full article

Brewer’s spent grain (BSG), the main lignocellulosic by-product of the beer industry, represents an abundant yet underutilized resource with high potential for valorization. This study presents an integrated biorefinery approach to convert BSG into second-generation (2G) ethanol, bioactive vinasse for plant growth promotion, and fungal biomass as a potential mycoprotein source. The biomass was first subjected to biological delignification using the white-rot fungus Ganoderma lucidum, after which two valorization routes were explored: (i) evaluation of the fungal biomass as a mycoprotein candidate and (ii) alcoholic fermentation for ethanol production. For the latter, three pretreatment strategies were assessed (diluted sulfuric acid and two deep eutectic solvents (DESs) based on choline chloride combined with either glycerol or lactic acid) followed by a one-pot enzymatic saccharification and fermentation using Kluyveromyces marxianus SLP1. The highest ethanol yield on substrate (Y_P/S) was achieved with [Ch]Cl:lactic acid pretreatment (0.46 g/g, 89.32% of theoretical). Vinasse, recovered after distillation, was characterized for organic acid content and tested on Solanum lycopersicum seed germination, showing promising biostimulant activity. Overall, this work highlights the potential of BSG as a sustainable feedstock within circular economy models, enabling the production of multiple bio-based products from a single residue. Full article

Xylooligosaccharides (XOS) are functional oligosaccharides with recognized prebiotic properties and growing industrial relevance, typically obtained through enzymatic depolymerization of xylan-rich lignocellulosic substrates. In this study, a recombinant endo-β-1,4-xylanase (XynA) from Clostridium acetobutylicum was employed for XOS production. The xynA gene was cloned into the expression vector pET-21a(+) and heterologously expressed in Escherichia coli BL21(DE3) under induction with isopropyl β-D-1-thiogalactopyranoside (IPTG). The recombinant protein, with an estimated molecular mass of 37.5 kDa, was verified by SDS-PAGE and Western blot analysis. Functional characterization via thin-layer chromatography revealed that XynA efficiently hydrolyzed beechwood xylan and rye arabinoxylan, predominantly yielding xylobiose. Additionally, the enzyme catalyzed the conversion of xylotriose into xylobiose and trace amounts of xylose. Notably, XynA demonstrated hydrolytic activity against autohydrolysed and alkali-pretreated coconut husk biomass, facilitating the release of XOS. These results underscore the potential of C. acetobutylicum XynA as a biocatalyst for the valorization of lignocellulosic residues into high-value oligosaccharides. Full article

Valorizing agri-food waste through black soldier fly larvae (BSFL) bioconversion offers a promising path to enhance circular and sustainable food systems. This study used attributional Life Cycle Assessment (LCA) to evaluate the environmental performance of BSFL reared on six agro-industrial residue diets: tomato, pea, onion, chickpea, wheat, and liquid digestate. The Environmental Footprint 3.1 method was used to assess multiple impact categories. The rearing trials were conducted in a dedicated pilot plant (13.5 m × 2.5 m × 2.7 m) that can treat about 1.58 t of residue per cycle. From the results, BSFL biomass yields were similar across diets, with 12–15% bioconversion and 70–85% substrate reduction. BSFL protein had higher impacts than fishmeal and pea protein but was comparable to soybean meal. BSFL lipids had greater impacts than rapeseed, palm, and sunflower oils yet were similar to soybean oil for bioenergy from fat. Electricity use for climate control was the main hotspot (~85%). Scenario analysis showed that using residual heat for climate control and scaling up via optimization could cut impacts by over 80%. The findings demonstrate the potential for producing BSFL on a medium-to-large scale to enhance circularity in the agri-food sector. Full article

Açaí, a berry emblematic of Amazonian biodiversity, is a major Brazilian product whose market value is largely concentrated in its pulp, leaving the residual biomass—particularly the fibrous seed—underexploited and typically discarded in landfills, with negative environmental and social consequences. To address this gap, this study employs a systematic technology roadmapping approach, integrating bibliometric analysis, patent landscaping, and expert consultations to consolidate fragmented data. This methodology enables the mapping of innovation trajectories across technology readiness levels, product categories, market segments, and key stakeholders. The roadmap identifies emerging trends and opportunity windows for valorizing açaí biomass via integrated biorefinery approaches, moving beyond traditional low-complexity uses such as thermal energy and seed-derived coffee substitutes. The highlighted products include pharmaceutical extracts, cosmetic ingredients, nanopapers, and cellulose nanocrystals, leveraging the biomass’s biochemical composition, notably antioxidants, mannose, and inulin. This methodological framework facilitates a dynamic analysis of technological maturation and market evolution, offering strategic insights to guide industrial investments and policy development. Findings indicate that biorefinery integration enhances resource efficiency and product diversification, situating açaí biomass valorization within broader bioeconomy strategies. The study demonstrates the efficacy of technology roadmapping in structuring prospective innovation pathways and in supporting the sustainable utilization of the Amazonian biomass. Full article

The growing worldwide demand for essential oils (EOs) brings new opportunities for Azorean Cryptomeria japonica aerial parts waste valorization. Therefore, the phytochemical and bioactivity investigation of EOs from different Azorean C. japonica tissues, such as twigs (Az–CJT), remains imperative to add more value to C. japonica’s EO industry, alongside the contribution to the local sustainable circular bioeconomy. This study provides, for the first time, GC–MS analysis and brine shrimp toxicity of the EO hydrodistilled from Az–CJT and aims to compare these parameters with those determined for a commercial Azorean C. japonica (branches and foliage) EO obtained through steam distillation. The main Az–CJT EO components were α-eudesmol (19.53%), phyllocladene (14.80%), elemol (12.43%), nezukol (11.34%), and γ-eudesmol (5.32%), while α-pinene (28.62%), sabinene (24.30%), phyllocladene (5.10%), β-myrcene (5.09%), and limonene (4.93%) dominated in the commercial EO. Thus, Az–CJT EO exhibited the highest sesquiterpenoids (43.52%), diterpenes (20.85%), and diterpenoids (13.21%) content, while the commercial EO was dominated by monoterpenes (74.61%). The Az–CJT EO displayed significantly higher toxicity than the commercial EO, with mortality rates of 87.7% and 16.9%, respectively, at 100 µg/mL. This result is likely related to the substantially higher terpenoid content of Az–CJT EO (61.20% vs. 9.44%), largely attributed to the sesquiterpenoid fraction. Due to its distinct chemical profile, Az–CJT EO may have differential commercial applications, warranting further investigation into its bioactive value and safe use. In conclusion, this study adds knowledge on the potentialities of C. japonica aerial parts’ EOs from the Azorean region. Full article

The increasing emphasis on environmental sustainability has placed biomass as a versatile and renewable resource, while the management and disposal of forest byproducts remain a significant challenge. This study explores the valorization of forest biomass residues derived from Pinus pinaster, Pinus pinea, and the invasive species Acacia dealbata, with a focus on their potential application as bioadsorbents. A comprehensive physicochemical characterization was conducted for different biomass fractions (leaves, needles, and branches of varying diameters). Leaves and needles contained higher amounts of extractives (from 7.7% in acacia leaves to 18.8% in maritime pine needles) and ash (3.4 and 4.2% in acacia leaves and stone pine needles, respectively), whereas branches contained more holocellulose (from 59.6% in P. pinea small branches to 79.2% in P. pinaster large branches). ATR-FTIR and pHpzc analyses indicated compositional and surface charge differences, with higher pHpzc values in A. dealbata relative to Pinus. TG analysis showed that acacia large branches degraded at a lower temperature (320 °C) compared to Pinus species (440–450 °C). Overall, the findings highlight the suitability of these underutilized forest byproducts as bioadsorbents, contributing to the advancement of circular economy practices. Full article

This study reports the initial thermal and thermochemical performance of a novel solarized Auger-type reactor for Pyrolysis (SARP), specifically developed for the valorization of organic solid waste into solar-derived fuels. A key innovation of this system lies in its integration with a high-flux, point-focus solar concentrator that enables controlled delivery of concentrated solar radiation to drive endothermic processes. At the front of the reactor, the thermal evaluation under solar irradiation shows that surface temperatures reached up to approximately 750 °C on the exterior, while the hottest section of the interior briefly reached approximately 700 °C, in the pyrolysis zone. In contrast, the preheating zone inside the reactor exhibits temperatures ranging from 160 °C to 306 °C, indicating a non-uniform thermal profile for the incoming feedstock. The campaign focused on thermochemical pyrolysis, in which pecan walnut tree pruning residue biomass was processed under controlled semicontinuous operation. Batches of 600 g were pyrolyzed, yielding approximately 390 g of biochar and achieving a peak hydrogen concentration of 14.5% vol in the product gases. These findings demonstrate the reactor’s potential for solar-driven waste-to-fuel conversion. Full article

Phosphorus-based compounds play a crucial role in agricultural productivity. However, excessive phosphorus discharge into water bodies contributes to eutrophication. This study proposes a circular approach for phosphorus recovery and reuse through the thermal valorization of Posidonia oceanica residues, an abundant marine biomass along Mediterranean coasts. After energy recovery from this waste (12.3 MJ kg⁻¹), the resulting ash was assessed as an effective adsorbent for aqueous phosphorus removal. Batch experiments were conducted to evaluate adsorption kinetics and equilibrium, considering the influence of key operational variables, such as temperature, pH, and adsorbent dosage. Under optimal conditions, the material achieved a maximum retention of approximately 55–60 mgP g⁻¹. The Freundlich model successfully describes the equilibrium isotherm data, indicating a heterogeneous adsorbent and an overall endothermic process. Phosphorus removal was favored at basic pH values (9.5–10.5), where the monohydrogen phosphate predominates. Leaching tests further revealed that saturated material releases phosphorus and other minerals in a manner clearly dependent on the final pH, with higher phosphorus release under more acidic conditions. These results suggest that Posidonia ash could serve as a low-cost adsorbent while also acting as a potential phosphorus source in soils. Full article