Horse husbandry in Europe has shifted from agricultural production toward leisure, sport, and therapeutic uses in peri-urban areas. Consequently, horse manure has increasingly become a logistical, regulatory, and economic challenge. Controlled composting has long been recognised as a treatment option for horse manure, offering hygienisation, organic matter stabilisation, and improved nutrient predictability. However, despite its technical feasibility, composting remains underutilised in decentralised and small-to-medium horse-keeping systems. This study investigated the potential of compost-based value chains for horse manure within the EU. It combined a comparative literature analysis of horse manure composting with a systematic mapping of compost products, applications, and business models implemented across EU member states. Feedstock-specific properties of horse manure, including bedding-driven carbon-to-nitrogen ratios, emission dynamics, and hygienisation requirements, were linked to market pathways, regulatory frameworks, and organisational archetypes. Results showed that composting transforms horse manure from a disposal burden into a flexible platform for differentiated products, primarily positioned as soil improvers rather than high-effect nitrogen fertilisers. Effective value creation depends on application-driven compost formulation, process control to ensure hygienic and agronomic quality, and organisational models that match spatial context, scale, and regulatory conditions. Centralised, municipal, and decentralised business models each present distinct advantages and constraints, while product differentiation through compost-biochar blends or growing media components offers emerging opportunities. Overall, the study demonstrated that integrating compost science with business model design is essential for unlocking the economic and environmental potential of horse manure in European peri-urban systems.
Potato peel waste (PPW), a major byproduct of the U.S. potato processing industry, is rich in organics of which a major part is lignocellulosic. This study evaluated the influence of thermal pretreatment (165–185 °C, 15 min) on the anaerobic degradability of PPW. Pretreatment improved feedstock solubilization, liberating up to 8.9
Brown seaweeds are the rich source of valuable bioactive compounds with vital bio-functional properties. The present study explores the use of hot water as a green solvent for extraction of bioactive compounds from brown seaweeds (Sargassum polycystum, Turbinaria ornata and Rosenvingea intricata). Extraction was performed at different temperature conditions such as 28.5 °C (A), 70 °C (B) and 90 °C (C). Yield and antioxidant ability of the seaweed extracts was assessed in terms of total phenolic, flavonoid, ferric reducing antioxidant power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, DNA nicking assay, and deoxyribose assay. Results showed that the extraction carried at temperature 90 °C showed significantly (p < 0.05) higher yield of 9.18 ± 0.03
The growing global population has led to a surge in agricultural production, generating vast quantities of lignocellulosic waste biomass. Biomass valorization through sustainable bioprocesses is a promising approach to reduce environmental burden and promote the circular economy. In the present study, a thermophilic fungus isolated from fermented paddy straw was used to produce enzymes and putative bioactive compounds via solid-state fermentation (SSF) using five different lignocellulosic substrates: banana fiber, rice bran, wheat bran, cotton stalk, and corn cob. Morphological and molecular characterization using ITS sequencing confirmed that the isolate was Aspergillus fumigatus PSF1. Compositional analysis of raw and fermented biomass revealed substantial reductions in the contents of cellulose (2.27–17.6
To address the issues of low hydration efficiency, inhibited hydration by early hydration film and restricted application of all-solid-waste cementitious materials due to chloride ions, this study uses kanbara reactor desulfurization slag (KRDS) and soda residue (SR) to construct a dual-alkaline solid waste synergistic activation system, forming the KRDS-SR-ground granulated blast-furnace slag (GGBS)-fly ash (FA) (KSGF) system with GGBS and FA. By adjusting mix proportions, compressive strength and fluidity tests were conducted to characterize macroscopic properties, while X-ray diffraction (XRD), thermogravimetric analysis (TG-DTG), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) were used to analyze the hydration mechanism. Results show that the dual‑alkaline system accelerates hydration, and the calcium‑chloride synergistic effect breaks the hydration film, reduces porosity and improves thermal stability. Layered hydrocalumite enables solidification of chloride, decreasing free chloride ions and promoting the application of all-solid-waste cementitious materials.
The accumulation of coal gangue (CG) poses severe environmental hazards, largely due to its low valorization rate. This study investigates the enhancement of mechanical properties of low-carbon cementitious composites incorporating microwave-activated CG under microwave curing. The CG was activated using various microwave heating regimes, and the resulting pozzolanic activity was assessed through both direct and indirect methods. Cementitious composites with microwave-activated CG were subjected to different microwave curing regimes. Their mechanical properties, hydration products, and pore structures were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The results show that microwave activation at 800 °C for 20 min provides the highest pozzolanic activity of CG, with the pozzolanic activity index reaching 70.91
Algal biomass is a versatile feedstock for renewable fuels and bioproducts, but its technical potential does not automatically translate into environmental or commercial viability. This review critically integrates the complete algal-biofuel chain, including strain selection, cultivation-system design, harvesting and dewatering, genetic and metabolic engineering, biomass pretreatment, biochemical conversion, and thermochemical conversion. Unlike reviews that examine individual unit operations or single fuel routes, the present work compares technologies using common decision criteria: biomass and product productivity, moisture tolerance, energy and chemical demand, scalability, technological maturity, environmental burden, and economic feasibility. Open ponds, closed photobioreactors, and hybrid cultivation strategies are evaluated in relation to contamination control, productivity, capital intensity, and operational energy. Pretreatment methods are assessed according to cell-disruption efficiency, net energy recovery, reagent requirements, downstream compatibility, and industrial applicability. Conversion pathways are then compared to show that no single route is optimal for all feedstocks: transesterification is most defensible for consistently lipid-rich biomass, anaerobic digestion is suitable for wet residues and wastewater-grown biomass, and hydrothermal liquefaction is promising for wet whole-biomass conversion but requires effective biocrude upgrading and nutrient recovery. The review further examines life-cycle trade-offs, water and nutrient demand, carbon accounting, production costs, policy dependence, and the role of co-products. A structured research roadmap is proposed to move the field from isolated yield maximisation toward integrated, seasonally validated, mass- and energy-balanced algal biorefineries.
Graphite oxide (GO) and its derivatives are widely used as adsorbents for metal cations in aqueous media. Nevertheless, relatively few studies have addressed the recovery, disposal, or value-added utilization of these metal-loaded adsorbents. In this study, the metals loaded by GO and its carboxymethylated derivatives (CMGO) were recycled to make effective liquid crystal materials. As a preliminary study, the adsorption experiments were conducted under fixed conditions to compare metal uptake capacities. In this work, the adsorbents were exposed to aqueous solutions of three divalent metal ions and subsequently evaluated. The CMGO provided the highest content of metal cations (68.57 mg g−1 Cu+2, 98 mg g−1 Zn+2 and 83.5 mg g−1 Cd+2). A variety of techniques, including atomic absorption, FT-IR, XRD, atomic force microscope (AFM), and polarizing optical microscope (POM), are used to evaluate the GO and modified GO. It is interesting to note the favourable liquid–crystal behaviour of metal-loaded GO and CMGO, as indicated by a decrease in the critical concentration, defined as the minimum concentration at which birefringence is observed under POM, from 0.063 to 0.125 mg mL−1 for M-GO(II) and M-CMGO(II) to 0.016 mg mL−1. This critical value is more favourable than that reported in the literature for carbon-based liquid crystals. Chelation of GO/CMGO with divalent metal ions enhanced metal–oxygen coordination, improved platelet organization, and promoted liquid crystalline behavior with lower critical transition concentrations, enabling the sustainable conversion of metal-loaded carbon-based adsorbents into functional materials.
This work focuses on the development of novel hydrochars from flax straw using hydrothermal carbonization (HTC) process, and their conversion into innovative pellets using a lignin binder produced from wheat straw. HTC was performed at 180–220 °C for 1 to 4 h, producing hydrochar with improved carbon content, reduced ash, higher heating values, and enhanced hydrophobicity. At 220 °C and 4 h, the hydrochar achieved 60.2
Organic waste, such as crop straw and vegetable trimmings, contains a high proportion of lignocellulose that highly reduces the fermentation efficiency of traditional composting and results in a treatment cycle of one to two months or longer. Therefore, screening and isolating microorganisms capable of efficiently degrading lignocellulose are necessary. In this study, fungi with high lignocellulose-degrading ability were screened to explore their effects on the composting of lignocellulosic waste. Among the eight isolated and purified fungal strains, strain MX4 produced the largest transparent and reddish-brown chromogenic circles on PDA-CMC and PDA-guaiacol plates, and was identified as Irpex lacteu MX4. Inoculation with I. lacteus MX4 at the cooling stage increased the lignocellulose degradation rate by 45.6
Drinking water treatment sludge (DWTS), also known as alum sludge (AS), a by-product of water purification, poses significant environmental disposal challenges due to its volume and potential toxicity. Recent research highlights sustainable reuse pathways for AS, particularly in cement-based construction materials, to mitigate environmental impacts and promote resource recovery. However, existing reviews overlook the distinct chemistry and reuse potential of alum-derived sludge. This review systematically addresses this gap through the first dedicated synthesis of AS characterization, construction applications, geotechnical performance, environmental safety, and economic feasibility. AS contains silica-alumina phases with pozzolanic activity after appropriate processing (drying, grinding, calcination), enabling its partial replacement of cement or aggregates in concrete, bricks, tiles, and lightweight aggregates. Incorporating low percentages (≤ 10
The growing global fish production has generated large volumes of fish waste and by-products, posing significant economic and environmental challenges. Recycling these materials has emerged as a promising strategy to produce high-value biomaterials from underutilized resources. In this context, this study aimed to conduct a systematic literature review, structured according to the Population-Concept-Context (PCC) framework and reported following the PRISMA guidelines, based on a search of PubMed, Scopus, and Web of Science covering publications from 2015 to 2025. The review focused on technological innovations in gelatin extraction from fish by-products and the development of biofilms, nanocomposites, and nanofibers for food packaging and biomedical applications. After applying the eligibility criteria, 45 studies were included. The analysis showed that electrospinning and solvent casting were the predominant fabrication techniques, reflecting the intrinsic molecular characteristics of fish gelatin. Biofilms and nanocomposite films were mainly developed for food packaging because of their favorable mechanical and barrier properties, whereas nanofibers were predominantly explored for biomedical applications owing to their porous architecture and high surface area. The incorporation of natural or synthetic additives generally improved the mechanical, thermal, barrier, and biological properties of fish gelatin-based materials. Despite these advances, the review identified important research gaps, including the lack of standardized extraction and characterization protocols and the limited correlation between structural characterization and functional performance. Future studies should establish robust structure–property relationships to accelerate the industrial application of fish gelatin-based materials.
Lignocellulosic residues like hazelnut shells are enormously produced by the hazelnut processing industry and locally burned at most. Utilization of hazelnut shells in bioprocesses could reduce air pollution and enhance the bioeconomy. The formation of microbial fermentation inhibitors during lignocellulosic pretreatment is a challenge for bioprocessing. Biological detoxification is a promising strategy to address this problem. This study used the adaptive approach by repeated growth to improve biomass generation of B. subtilis in the hazelnut shell hydrolysate under various cultivation conditions of pH (5, 6, and 7) and inoculum ratios (2, 5, and 10
The hydrolytic hydrogenation of cellobiose (a cellulose model compound) has been studied over Ru monometallic catalysts supported on functionalized carbons. The supports (Cas and BCf) were synthesized in the laboratory, and, in particular BCf was obtained from the pyrolysis of lignocellulosic biomass derived from pruning waste. The catalysts, presenting both acidic and hydrogenating functions have been characterized by SEM, Boehm titration, FT-IR, TGA-DTA, ICP-MS, TEM and N2 physisorption. With Cas and BCf supports, a cellobiose conversion of 90
Native to South America, Araucaria angustifolia bracts (an underutilized by-product of seed processing) account for nearly 80
Corn cob is one of the most generated agro-wastes worldwide that serves as a potential low-cost raw material for producing different value-added chemicals under the biorefinery philosophy. In this paper, corn cob was treated using a sequential mild acid-alkaline oxidative treatment to produce fermentable sugars and crystalline cellulose. During the acid hydrolysis, hemicellulose and amorphous cellulose were transformed into monomeric sugars achieving the maximum yield (38.92 g / 100 g corn cob) at 110 °C and 180 min with 5
Microbial fuel cells (MFCs) offer a sustainable approach for simultaneous energy recovery and wastewater treatment. However, their performance is often limited by competition from methanogens in mixed-culture systems. In this study, dead biomass of Chaetoceros calcitrans was evaluated as an anodic substrate and compared with Chlorella vulgaris in dual-chamber MFCs. Anaerobic sludge was pretreated with algal biomass to assess methanogen inhibition and its influence on electrochemical performance. The MFC fed with Chaetoceros produced a higher maximum operating voltage (492 ± 2 mV) and average current (4.26 ± 0.2 mA) than the Chlorella-fed MFC (474 ± 3 mV and 3.84 ± 0.3 mA). Polarization analysis showed lower internal resistance in the Chaetoceros system (90 Ω) compared with the Chlorella system (200 Ω), indicating improved anodic activity. Although COD removal was slightly higher in the Chlorella-fed MFC (75 ± 7
The intensive growth of the poultry industry generates large volumes of poultry sewage sludge (PSS), which pose an environmental challenge due to their high organic and microbiological load. In this study, the quality and kinetics of probiotic biomass production of Lactobacillus plantarum were evaluated through the anaerobic biotransformation of said sludge previously thermally pretreated. Three inoculum concentrations (5, 10, and 15
The increasing demand for rare earth elements (REEs), particularly neodymium is driving the search for sustainable recovery pathways within Europe’s green transition. This study presents an integrated upcycling strategy for neodymium-iron-boron (NdFeB) permanent magnets, combining solid-state chlorination with selective separation techniques to efficiently recover neodymium, iron, and boron. The process achieves a REE recovery yield of 99.8 ± 0.1
The present study investigates the efficacy of three commercially available food-grade proteases – trypsin, papain and flovourzyme – on the physicochemical, structural, and techno-functional properties of protein hydrolysates prepared from the underutilised Asiatic hard clam, Meretrix meretrix. The Clam protein hydrolysate (CPH) exhibited distinct characteristics depending on the enzyme used, showing differences in proteolytic specificity and hydrolytic efficiency. Trypsin (CPHT), produced the highest degree of hydrolysis (49.63
