Search Results (106)

Potassium (K) fertilization plays a key role in regulating stem morphology, particularly stem diameter, yet the influence of different K fertilizer formulations on stem structure and tensile strength remains insufficiently understood. Cereal straw is a key lignocellulosic by-product with growing importance in the circular bioeconomy. Thus, the aim of this study was to determine the links between potassium nutrition, stem structure, and mechanical behavior for four cereal species: wheat, barley, rye, and oats. There were three potassium fertilization levels (0, 60, and 120 kg K ha⁻¹) conducted in a field experiment in eastern Croatia (2021/2022). At maturity, stem morphology, macroelements (Ca, K, P, C, N), acid detergent fiber (ADF), neutral detergent fiber (NDF), and uniaxial tensile properties (maximum force, tensile strength, Young’s modulus) were determined. Cereal species was the dominant source of variation (p < 0.0001) for all traits, whereas the main effect of K was generally weak and significant only for stem diameter at the midpoint and N concentration, although K × species interactions were frequent. Oats and rye showed the most vigorous biomass production, whereas wheat exhibited by far the highest tensile strength (about 120 MPa) and stiffness (6.23 GPa), together with the highest ADF, while barley had the greatest NDF. Oat stems had the lowest ADF and NDF, indicating less lignified, more digestible tissues but mechanically weaker straw. Mechanical traits were tightly and positively correlated with ADF, NDF, and CN ratio, whereas P showed weak or negative associations with plant size and strength. Therefore, for targeted straw valorization, cereal species selection is paramount, with potassium fertilization playing a secondary, species-dependent role. Full article

Driven by the energy transition within the framework of the United Nations Framework Convention on Climate Change, second-generation (2G) ethanol stands out as a technical and sustainable alternative to fossil fuels. Although first-generation ethanol, produced from saccharine and starchy feedstocks, represents an advance in mitigating emissions, its expansion is limited by competition with areas destined for food production. In this context, 2G ethanol, obtained from residual lignocellulosic biomass, emerges as a strategic route for diversifying and expanding the renewable energy matrix. Thus, this work discusses the current state of 2G ethanol technology based on the gradual growth in production and the consolidation of this route over the last few years. Industrial second-generation ethanol plants operating around the world demonstrate the high potential of agricultural waste as a raw material, particularly corn straw in the United States, which offers a lower cost and significant yield in the production of this biofuel. Similarly, in Brazil, sugarcane by-products, especially bagasse and straw, are consolidating as the main sources for 2G ethanol, integrated into the biorefinery concept and the valorization of by-products obtained during the 2G ethanol production process. However, despite the wide availability of lignocellulosic biomass and its high productive potential, the consolidation of 2G ethanol is still conditioned by technical and economic challenges, especially the high costs associated with pretreatment stages and enzymatic cocktails, as well as the formation of inhibitory compounds that compromise the efficiency of the process. Genetic engineering plays a particularly important role in the development of microorganisms to produce more efficient enzymatic cocktails and to ferment hexoses and pentoses (C₆ and C₅ sugars) into ethanol. In this scenario, not only are technological limitations important but also public policies and tax incentives, combined with the integration of the biorefinery concept and the valorization of (by)products, which prove fundamental to reducing costs, increasing process efficiency, and ensuring the economic viability and sustainability of second-generation ethanol. Full article

Anaerobic digestion of straw is a crucial method for agricultural waste valorization, yet its efficiency is limited by complex factors. This study employed machine learning to predict methane yield and optimize process parameters in biochar-amended straw digestion. A comprehensive dataset integrating experimental and literature data (100 samples, 15 input variables) was constructed, incorporating operational conditions, straw characteristics, and biochar properties (e.g., dosage, particle size, specific surface area, and elemental composition). Prediction models were developed using Random Forest (RF), XGBoost, and Support Vector Machine (SVM). Results indicated that the RF model achieved the best predictive accuracy, with an R² of 0.81 and RMSE of 36.9, significantly surpassing other models. Feature importance analysis identified feeding load, biochar dosage, and biochar carbon content (C%) as the key governing factors, collectively accounting for 65.7% of the total contribution. The model-predicted optimal ranges for practical operation were 15–30 g for feeding load and 5–20 g/L for biochar dosage. This study provides data-driven validation of biochar’s enhancement mechanisms and demonstrates the utility of RF in predicting and optimizing anaerobic digestion performance, offering critical support for sustainable agricultural waste recycling and clean energy generation. Full article

Biochar is one of the most promising crop straw utilization pathways. However, its capacity for adsorbing heavy metals is limited, and there is a potential risk of secondary pollution, highlighting the importance of developing efficient and environmentally friendly bio-modification methods. Here, we utilized glomalin-related soil protein (GRSP), a byproduct from arbuscular mycorrhizal fungi, to modify straw biochar, developing a novel composite material and systematically evaluating its performance in removing copper ion (Cu²⁺) from aqueous solutions. Biochar samples derived from maize, wheat, and rice straw were prepared at three pyrolysis temperatures (300 °C, 500 °C, and 700 °C), followed by surface functionalization with GRSP to produce GRSP-modified straw biochar for Cu²⁺ adsorption experiments. The results demonstrated that the abundant functional groups (e.g., amino and carboxyl groups) in GRSP and the porous structure of the straw biochar exhibited a significant synergistic effect, enhancing the adsorption capacity for Cu²⁺. Notably, the GRSP-modified wheat straw biochar prepared at 700 °C achieved an adsorption capacity of 193.2 mg g⁻¹ for Cu²⁺, representing a 76% improvement over the unmodified material. Fourier transform infrared spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectroscopy revealed that hydroxyl, carboxyl, and ether groups served as key adsorption sites for Cu²⁺, while the hydrophobic-acid precipitation characteristics of GRSP further enhanced the material’s recoverability. By systematically characterizing the material’s microstructure and its adsorption behavior toward Cu²⁺, this study elucidated the role of critical functional groups in the adsorption mechanism. This work not only offers a low-carbon and efficient strategy for agricultural waste valorization and heavy metal pollution control, but also advances the mechanistic understanding of “bio-abiotic” synergy in environmental remediation. Full article

The massive accumulation of agricultural waste, such as wheat straw, and its disposal by burning pose significant environmental challenges. This study explores a sustainable solution by converting wheat straw into composite superabsorbent polymers (SAPs)—superabsorbents contain both synthetic and biodegradable fragments—for improved agricultural water and nutrient management. Wheat straw (WS) was sequentially processed via acid and alkaline hydrolysis to yield fractions with different lignin contents, which were then carboxymethylated (CMWS-Ac and CMWS-Al) to enhance hydrophilicity. These derivatives were incorporated at 20 and 33 wt. %. into SAPs synthesized by copolymerization with acrylamide and acrylic acid. The CMWS-Al-based SAPs exhibited superior properties, including higher equilibrium swelling ratios (up to 566 g/g in water), excellent mechanical strength, and robust gel structure, as confirmed by rheological studies. Furthermore, SAPs demonstrated a significant capacity to retain urea in sand columns, with SAP-CMWS-Al-33 achieving 56% urea retention, highlighting their potential for mitigating fertilizer leaching. The results establish a correlation between the extent of straw processing, the physicochemical properties and lignin content of the derivatives, and the performance of the final SAPs. These wheat straw-based SAPs present a promising, sustainable technology for enhancing soil moisture retention, improving fertilizer use efficiency, and valorizing agricultural waste. Full article

This study presents a complete and zero-waste valorization strategy for barley straw through the synthesis of bio-polyols and the concurrent utilization of its cellulose fraction as lignin-containing cellulose nanofibers (LCNF) for the development of bio-based polyurethane (PU) foams. Two types of bio-polyols were prepared: one derived from lignin isolated via biomass fractionation, named lignin bio-polyol (LBP), and another obtained directly from unfractionated barley straw, called straw bio-polyol (SBP), thereby incorporating all lignocellulosic constituents into a single reactive matrix. LCNF, produced from the same feedstock, was incorporated at different loadings to achieve full biomass utilization and reinforce the polyurethane foam structure. Foams prepared with LBP exhibited lower density and a more homogeneous structure, whereas those synthesized with SBP developed a stiffer, more crosslinked network. The incorporation of LCNF generally increased apparent density and mechanical performance, with optimal reinforcement at 3 wt.% in foams with SBP and 5 wt.% in LBP foams, corresponding to a 62.5 and 121% enhancement in compressive strength relative to their respective control foams. Moreover, the use of barley straw bio-polyol shifted some thermal degradation peaks toward higher temperatures, evidencing improved thermal resistance. Overall, this dual-route strategy provides a sustainable and versatile methodology for the comprehensive valorization of lignocellulosic biomass, enabling a systematic understanding of the role of each structural component in polyurethane foam synthesis. The resulting materials offer a renewable, low-impact pathway toward high-performance polymeric materials. Full article

Agricultural and agro-industrial waste, produced in vast quantities worldwide, presents both environmental and economic challenges. Microbial valorization offers a sustainable solution, with bacterial cellulose (BC) emerging as a high-value product due to its purity, strength, biocompatibility, and biodegradability. This review highlights recent advances in producing BC from agricultural and agro-industrial residues via optimized fermentation processes, including static and agitated cultivation, co-cultivation, stepwise nutrient feeding, and genetic engineering. Diverse wastes such as fruit peels, sugarcane bagasse, cereal straws, and corn stover serve as cost-effective carbon sources, reducing production costs and aligning with circular bioeconomy principles. Advances in strain engineering, synthetic biology, and omics-guided optimization have significantly improved BC yield and functionalization, enabling applications in food packaging, biomedicine, cosmetics, and advanced biocomposites. Process innovations, including tailored pretreatments, adaptive evolution, and specialized bioreactor designs, further enhance scalability and product quality. The integration of BC production into circular bioeconomy models not only diverts biomass from landfills but also replaces petroleum-based materials, contributing to environmental protection and resource efficiency. This review underscores BC’s potential as a sustainable biomaterial and identifies research directions for overcoming current bottlenecks in industrial-scale implementation. Full article

Global antibiotic pollution (represented by tetracycline hydrochloride, TCH) threatens water environmental safety, and resource recovery of agricultural waste remains a key challenge for sustainable development. Given that utilizing biochar for adsorption is widely recognized as a circular economy-compliant method, this study aimed to verify its applicability in TCH pollution control while recycling agricultural waste by preparing modified biochar from the Xi Zang highland barley straw via chemical activation (KOH, H₃PO₄, NaHCO₃, and ZnCl₂) and pyrolysis at 750 °C. Among the products, H₃PO₄-modified (P-BC) and ZnCl₂-modified (Zn-BC) biochars performed best: their abundant micro/mesoporous structures and surface functional groups (–OH/–COOH) enabled excellent TCH adsorption, with the mechanism involving synergy of physical adsorption (dominated by pore filling) and chemical adsorption (hydrogen bonding, electrostatic attraction, cation bridging), alongside multi-layer adsorption. Adsorption was pH-dependent—acidic conditions favored it, while Zn-BC restored efficiency at pH = 9 via Zn²⁺ bridging. The two biochars were complementary: Zn-BC had higher adsorption capacity, while P-BC showed better stability and ionic interference resistance. Thus, Zn-BC suits high-concentration, low-ionic-strength TCH wastewater, and P-BC is ideal for complex high-ionic-strength water (e.g., industrial/aquaculture wastewater). This study provides theoretical and technical support for high-value utilization of regional agricultural waste and targeted TCH pollution control. Full article

Pleurotus giganteus, a heat-tolerant mushroom with high nutritional and medicinal value, is a promising species for tropical mushroom cultivation in Hainan, China. However, its current dependence on rubber sawdust as the primary substrate compromises environmental sustainability. In this study, we applied a “replacing wood with grass” strategy and used a simplex-lattice design to optimize substrate formulations based on agro-residues. Laboratory screening identified banana straw and chili straw as effective substitutes for rubber sawdust, supporting rapid and dense mycelial growth. Mixed formulations showed distinct advantages in mycelial growth, enzyme activity, agronomic traits (growth cycle, yield, and cap-to-stipe ratio), and nutritional composition compared to the control formulation (CF), particularly in terms of growth rate and laccase activity. Correlation analyses revealed that both individual ingredients and their interactions significantly affected mycelial growth and agronomic traits, with the magnitude and direction of effects depending on their relative proportions. Based on expected response values for key evaluation indices, an optimal formulation (9.97% rubber sawdust, 24.33% banana straw, 10.70% chili straw, 40% cottonseed hulls, 10% wheat bran, and 5% lime) was predicted and experimentally validated to outperform the CF. This study provides a sustainable basis for localized cultivation of P. giganteus in Hainan and supports the high-value valorization of agricultural residues for mushroom production. Full article

The transition toward sustainable panel technologies is driving intensive research on binderless boards and self-bonded lignocellulosic composites. Particleboard, an engineered wood composite made by hot pressing wood particles with synthetic adhesives, is among the most widely produced wood-based panels due to cost-effectiveness and versatility. However, pressure on forest-derived raw materials and concern over formaldehyde emissions are accelerating the search for renewable resources and greener routes. Residues and underutilized materials from agro-industrial, food, and forestry sectors (such as cereal straws, sugarcane bagasse, brewer’s spent grain, and fruit-processing by-products) offer a sustainable alternative, enabling waste valorization, lowering environmental burdens, and supporting circular bioeconomy models. Binderless boards, produced without adhesives, exploit natural bonding among lignocellulosic components, including lignin softening, thermoplasticization, and covalent crosslinking during hot pressing. This review adopts a complex network approach to systematically map and analyze the scientific landscape of binderless board production. Using citation-based networks from curated seed papers and their first- and second-degree neighbors, we identify thematic clusters, with cluster “A” as the research core. The examination of this cluster, complemented by word-cloud analysis of titles and abstracts, highlights prevalent raw materials and key research lines, like raw-material sources and lignocellulosic composition, processing parameters, and pretreatment strategies. Based on these findings, brewer’s spent grain is selected as a representative case study for cost analysis. This approach synthesizes the state of the art and reveals emerging directions, research gaps, and influential works, providing a data-driven foundation for advancing self-bonded lignocellulosic composites. 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

The high stability of chelated heavy metal complexes like Cu-EDTA renders their effective removal from industrial wastewater a persistent challenge for conventional treatment processes. This study developed a sustainable and high-performance CuO-modified biochar (CuO-BC) from corn straw waste for peroxydisulfate (PDS)-activated degradation of Cu-EDTA. Through systematic optimization, hydrothermal co-precipitation using copper acetate as the precursor followed by secondary pyrolysis at 350 °C was identified as the optimal synthesis strategy, yielding a dandelion-like structure with highly dispersed CuO on the BC surface. It achieved 93.8% decomplexation efficiency and 57.3% TOC removal within 120 min under optimized conditions, with an observed rate constant (K_obs) of 0.0220 min⁻¹—five times higher than BC. Comprehensive characterization revealed that CuO-BC possessed a specific surface area and pore volume of 4.36 and 15.5 times those of BC, along with abundant oxygen-containing functional groups and well-exposed Cu–O active sites. The enhanced performance is attributed to the synergistic effects of hierarchical porosity facilitating mass transfer, uniform dispersion of CuO preventing aggregation, and surface functional groups promoting PDS activation. This work presents a green and scalable approach to transform agricultural waste into an efficient metal oxide-BC composite catalyst, offering dual benefits of environmental remediation and resource valorization. Full article

Lignocellulosic agricultural residues represent a rich source of potential feedstock for biorefinery applications, but their valorization remains challenging. The white-rot fungus Irpex lacteus J2 exhibited a promising degradation effect, but its molecular mechanisms of lignocellulose degradation remained largely uncharacterized. Here, we performed high-quality whole-genome sequencing and untargeted metabolomic profiling of I. lacteus J2 during the degradation of corn straw as the sole carbon source. The assembled I. lacteus J2 genome contained 14,647 protein-coding genes, revealing a rich genetic repertoire for biomass degradation and secondary metabolite synthesis. Comparative genomics showed high synteny (mean amino acid sequence identity 92.28%) with I. lacteus Irplac1. Untargeted metabolomic analysis unveiled a dynamic metabolic landscape during corn straw fermentation. Dominant metabolite classes included organic acids and derivatives (27.32%) and lipids and lipid-like molecules (25.40%), as well as heterocyclic compounds (20.41%). KEGG pathway-enrichment analysis highlighted significant activation of core metabolic pathways, with prominent enrichment in global metabolism (160 metabolites), amino acid metabolism (99 metabolites), carbohydrate metabolism (24 metabolites), and lipid metabolism (19 metabolites). Fermentation profiles at 3 and 15 days demonstrated substantial metabolic reprogramming, with up to 210 upregulated and 166 downregulated metabolites. Correlation analyses further revealed complex metabolic interdependencies and potential regulatory roles of key compounds. These integrated multi-omics insights significantly expand our understanding of the genetic basis and metabolic versatility, enabling I. lacteus J2 to efficiently utilize lignocellulose. Our findings position I. lacteus J2 as a robust model strain and provide a valuable foundation for developing advanced fungus-based strategies for sustainable bioprocessing and valorization of agricultural residues. Full article

A significant quantity of agro-industrial waste is generated globally across various agricultural sectors and food industries. Composed primarily of cellulose, hemicellulose, and lignin—known as lignocellulosic materials—this waste holds significant potential and can be repurposed as a nutrient-rich substrate for mushroom cultivation. Therefore, mushroom cultivation can be regarded as a promising biotechnological approach for the reduction and valorization of agro-industrial waste. This investigation is the first to explore the utilization of agro-industrial waste- and by-products for the cultivation of Epicoccum nigrum for the production of extracts with valuable biological activities. The logistic curve and autocatalytic growth models were applied to study the kinetics of the growth process on wheat bran, sunflower cake, wheat straw, pine sawdust, and steam-distilled lavender straw substrates. Through mathematical modeling, the optimal composition of a nutrient medium containing the selected substrates was determined and successfully validated in experimental conditions. Biologically active water extracts were obtained after solid-state cultivation with α-amylase and cellulase activity up to 10.6 ± 0.6 U/mL and 0.52 ± 0.03 U/g, respectively. The extracts exhibited antimicrobial activity against fungal strains from six different species, and the most susceptible was the phytopathogen Sclerotinia sclerotiorum, with a minimum inhibitory concentration of 0.156–0.313 mg/mL. Full article

Lignocellulosic agro-forestry residues (LARs), such as rice straw, sugarcane bagasse, and wood wastes, are abundant and low-cost feedstocks for polyhydroxyalkanoate (PHA) bioplastics. However, their complex cellulose–hemicellulose–lignin matrix requires integrated valorization strategies. This review presents a dual-framework approach: “pretreatment–co-substrate compatibility” and “pretreatment–microbial platform matching”, to align advanced pretreatment methods (including deacetylation–microwave integration, deep eutectic solvents, and non-sterilized lignin recovery) with engineered or extremophilic microbial hosts. A “metabolic interaction” perspective on co-substrate fermentation, encompassing dynamic carbon flux allocation, synthetic consortia cooperation, and one-pot process coupling, is used to elevate PHA titers and tailor copolymer composition. In addition, we synthesize comprehensive kinetic analyses from the literature that elucidate microbial growth, substrate consumption, and dynamic carbon flux allocation under feast–famine conditions, thereby informing process optimization and scalability. Microbial platforms are reclassified as broad-substrate, process-compatible, or product-customized categories to emphasize adaptive evolution, CRISPR-guided precision design, and consortia engineering. Finally, next-generation techno-economic analyses, embracing multi-product integration, regional adaptation, and carbon-efficiency metrics, are surveyed to chart viable paths for scaling LAR-to-PHA into circular bioeconomy manufacturing. Full article