Biomass Conversion and Biorefinery最新文献

Lignin, a by-product from bio-refineries and paper industry available in huge volume, can be depolymerised by physico-chemical and biological methods into high value products. However, the physico-chemical methods have several constraints whereas biological conversion is a promising strategy for depolymerisation and bio-valorisation of lignin. This study targeted yeast strain Rhodotorula glutinis Y1 for its lignin degradation potential and production of value-added aromatics vanillin and ferulic acid using alkaline lignin substrate. R. glutinis Y1 grew well in minimal medium with upto 0.5% alkaline lignin achieving a maximum 37% degradation. The degradation increased to ~ 50% when lignin was co-metabolised in presence of glucose (1%), and accumulated 11.4 ppm vanillin and 30.47 ppm ferulic acid respectively. FT-IR analysis showed chemical modifications in the structure of degraded lignin. Rhodotorula constitutively elaborated extracellular lignolytic enzymes laccase (2.74 U/mL) and peroxidase (0.63 U/mL) in the presence of lignin and glucose. Decolorization of dyes, Congo red and Azure blue present in the medium, by Rhodotorula glutinis Y1 after 10 days incubation corroborated the lignolytic enzyme production. Lignin degradation was impacted by higher oxygenation with 200 rpm showing faster rate within 24 h as lignin degradation is highly oxidative process. Also, presence of easily metabolizable C-source glucose facilitated higher lignin degradation than complex substrates (cellulose and carboxy-methyl-cellulose). Supplementing complex nitrogen source had profound effect as peptone maximally promoted growth and lignin degradation (~ 60%) accumulating 135 ppm vanillin while soybean extract showed highest vanillin accumulation (316 ppm). The study demonstrates proof of concept for biobased vanillin production from lignin.

Depleting fossil fuel reserves, rising energy demand, and increasing environmental concerns have accelerated the search for renewable and sustainable alternatives for fuels and chemicals. Lignocellulosic biomass (LB) is an abundant and renewable feedstock with significant potential for the production of bioethanol, biochemicals, and other value-added products. However, its efficient utilization is hindered by the recalcitrant structure of the lignocellulosic matrix, primarily due to intricate and complex interactions among cellulose, hemicellulose, and lignin coupled with high crystallinity of cellulose, which render its fractionation extremely challenging. Therefore, an effective pretreatment step is essential to disrupt the biomass structure and improve enzymatic accessibility to constituent polysaccharides. Among various pretreatment technologies, ionic liquid (IL)-based pretreatment has emerged as a promising approach owing to its ability to effectively deconstruct LB under ambient conditions with enhanced enzymatic saccharification, and reduced inhibitors formation. Recently, ILs are being investigated as promising, efficient and eco-benign LB pretreatment agents. This review provides a comprehensive overview of IL-based pretreatment of LB, including fundamental properties of ILs, their pretreatment mechanisms, factors influencing their performance, toxicity, recovery, recyclability, and recent advances in IL-integrated pretreatment strategies. Further, the review examines the production of biofuels and value-added bioproducts from IL-pretreated biomass, nanotechnology-based approaches for IL pretreatment, and the emerging role of machine learning in IL design and process optimization. Additionally, it highlights techno-economic analysis and life cycle assessment for evaluating the economic feasibility and environmental sustainability of IL-based biorefineries.

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The rapid expansion of the global açaí (Euterpe oleracea) market has led to an alarming increase in waste generation, particularly seeds and fibers, posing significant environmental challenges. This review explores innovative strategies to repurpose these residues through cutting-edge technologies, including nanotechnology for nanocellulose production, microbial fermentation for biopolymer synthesis, and green extraction methods for obtaining bioactive compounds. Emphasis is placed on the development of high-value-added products such as biodegradable plastics, biomaterials, and renewable energy sources, aligning with the principles of the circular economy. Additionally, the review highlights the socioeconomic potential of these innovations and their role in mitigating environmental impacts. A focus is given to the need for sustainable practices and policy-driven initiatives to maximize the value of açaí residues, calling for solutions to overcome technological and economic barriers while promoting sustainable development in the Amazon region.

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The figure illustrates the various applications of açaí within the concept of circular economy, highlighting how different parts of the fruit and its waste can be used sustainably. In the center, açaí is presented as the main raw material, with ramifications for five sectors: cosmetics, biofertilizers, nutraceuticals, biopolymers and biofuels. In the cosmetics area, bioactive compounds are used in skin and hair products. Organic waste is used in the production of biofertilizers, while nutraceuticals take advantage of the fruit's natural antioxidants. Biopolymers are obtained from lignocellulosic waste, with a focus on biodegradable materials. Biofuels use oils and biomass to generate renewable energy. The proposal aims to reduce waste, add value to byproducts and strengthen the sustainability of the açaí production chain

In this study, biomass chitosan (CS) was used as the raw material and potassium tetraxalate dihydrate (KH₃C₄O₈·2H₂O) as the activator. Porous carbon material (CK-M-T) was prepared by one-step activation method for efficient CO₂ capture. The synergistic regulatory mechanism of activation temperature (600–800℃) and activator ratio (CS / KH₃C₄O₈·2H₂O mass ratio 1:3 − 1:5) on the microstructure, and surface chemical properties of materials was systematically investigated. The specific surface area and micropore volume of the CK-0.25-700 (prepared with a CS / KH₃C₄O₈·2H₂O ratio of 0.25 and pyrolysis temperature of 700 °C) are the highest, reaching 967 m³/g and 0.44 cm³/g respectively. Its three-dimensional disordered porous structure (SEM/TEM) and abundant micropores (1–3 nm) provide ideal channels for CO₂ adsorption. At 273 K/298 K, the CO₂ adsorption capacity of CK-0.25-700 reached 129.78/77.47 cm³/g, which was significantly better than that of samples under other conditions. The IAST model calculation shows that its selectivity for CO₂/N₂ (10/90) reaches 20 (298 K, 1 bar). The isosteric heat of adsorption (25.4–27.8 kJ/mol) confirmed that physical adsorption was dominant, leading to low regeneration energy consumption. After 20 adsorption-desorption cycles, the adsorption capacity remained stable, demonstrating outstanding cyclic stability-further confirming the material’s practical applicability. This work provides a new strategy for developing environmentally friendly and efficient porous carbon CO₂ adsorbents. The mild and environmentally friendly activation property of KH₃C₄O₈·2H₂O makes it a promising alternative to traditional corrosive activators, promoting the application of biomass carbon materials in the field of carbon capture.

A simple lignocellulosic biomass fractionation strategy using lactic acid as a medium was investigated with miscanthus as a reference feedstock. Lactic acid, a biobased and safe medium, offers a simple process. Two triggers were identified to improve the lignin recovery yield: temperature increase (from 100 to 125 °C) or addition of catalyst acid (either HCl, H₂SO₄, or p-toluene sulfonic acid, 0.1 N) allowed energy savings. Without process optimization, at 125 °C, the acidity of lactic acid was sufficient for achieving 65% delignification and recovering 36% of initial lignins, while the addition of acid catalyst allowed to limit the temperature to 100 °C while ensuring a delignification of 66% and a lignin recovery of 44%. In all cases, Klason lignin content of water insoluble fraction was 75%. On the studied range, the process conditions only slightly impacted molar mass distribution, but the choice of acid influenced lignin structures in terms of thioacidolysis yields and hydroxyl contents. Reactivity of lactic acid towards lignins in these conditions was studied through a model approach involving a β-O-4 dimer. The present paper does not report an optimized process, as the experimental work was not conducted in that aim, but rather a proof of concept opening a simple and safe route for delignification.

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A three-year field experiment was conducted (2019–2021) using biofuel ash (BA) and granulated ash with 30% ash in the granules (BAG30), granulated ash with 50% ash in the granules (BAG50), and granulated ash with 80% ash in the granules (BAG80) as fertilizer sources. Granules were made by hydration from BA and lime kiln dust (LKD). The study evaluated nutrient release from granules, primarily focusing on heavy metal accumulation and mobility in soil and plants through changes in nutrient and metal concentrations. The contamination factor (CF) and the pollution load index (PLI) were calculated to assess soil and plant contamination levels. Fertilization with BAG30, BAG50, and BAG80 resulted in a positive nutrient balance for calcium and magnesium, whereas a positive balance for potassium and phosphorus was achieved only with BA application. However, BA fertilization also resulted in the highest concentrations of heavy metals in grain and straw. Despite these increases, contamination levels remained low in all treatments, and PLI values indicated only moderate contamination in soil, grain, and straw. The findings suggest that BA and BAG fertilizers can enhance soil nutrient status with minimal environmental risk.

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About 80.2% of cellulose was left in sugarcane tops (SCT) after pretreatment with formic acid (FA), done at an optimized solid-to-liquid (S/L) ratio of 1:7.5, at 125 °C for 60 min in a two-step process. During organosolv pretreatment with FA, about 97.3% of hemicellulose and 95.6% of lignin were dissolved. In this process, about 19.8% of cellulose was lost. The process produced a hemicellulose-rich liquid (hydrolysate/ syrup) and lignin, both separated after organosolv pretreatment. FA used in the process was collected and recycled in the washing stage. From the saccharification of pretreated SCT, about 80.4 g/L of C-6 sugars was obtained after 96 h using an enzyme dose of 0.1 g/g substrate. Using 0.30% yeast extract and a mix of S. cerevisiae, Sc. stipitis, and P. tannophilus, up to 46.8 g/L of ethanol was produced. From 1 ton of SCT, the process yielded about 139 kg of ethanol, 130 kg of organosolv lignin, and 66.6 kg of furfural.

In this work, biodiesel was produced from high-free fatty acid Azadirachta indica (neem) oil using deep eutectic solvents as catalysts. Six DESs were synthesized and screened, having quaternary ammonium and phosphonium salts as hydrogen bond acceptors. The results show that the phosphonium-based toluene sulfonic acid-derived DES is the most active Brønsted-acid catalyst for FFA esterification. The process is systematically optimized by varying the oil: methanol molar ratio, esterification temperature, and catalyst loading. The optimum parameters obtained are 100 °C, a 1:5 oil-to-methanol ratio, and 3 wt%. In comparison to non-catalytic base processes that require temperatures of 180–220 °C, the DES pathway reduces thermal severity while significantly enhancing conversion efficiency. While the catalytic efficacy of phosphonium-based deep eutectic solvents has been demonstrated for feedstocks such as crude palm oil, a scarcity of comprehensive data was identified regarding the engine performance, combustion behavior, and emission profiles of biodiesel synthesized via this DES route. The present work was therefore designed to extend the investigation beyond synthesis to a full evaluation of the fuel's combustion, performance, and emission characteristics in a compression ignition engine. The engine performance and emissions assessment of the conventional diesel and biodiesel are evaluated at 1500 rpm at varying loads of 20–100%. The results showed that biodiesel exhibited higher brake-specific fuel consumption and slightly lower brake thermal efficiency due to lower heating value and distinct spray-evaporation behaviour. The emission results show that CO, CO₂, and hydrocarbons decrease notably in the exhaust gases, at the cost of increased NOx emissions.

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Biomass-derived geopolymers have attracted increasing attention as sustainable alternatives to ordinary Portland cement (OPC), valorizing agricultural, forestry, and industrial residues into low-carbon binders. A bibliometric analysis based on the Scopus database indicates a marked increase in research activity after 2018, with publication output peaking in 2023. China, India, Australia, and several European countries emerged as the leading contributors to this research field. Keyword mapping revealed four dominant research themes: strength and durability, biomass valorization, environmental remediation, and advanced applications such as 3D printing and composites. A critical review of representative studies showed that agricultural ashes, including rice husk ash (RHA) and sugarcane bagasse ash (SCBA), have demonstrated compressive strengths ranging from 30 to 72 MPa under different mix designs and curing conditions. Forestry residues, particularly wood fly ash and lignin, improved sulfate resistance and achieved adhesive bonding strengths of up to 3.8 MPa, while industrial biomass wastes, including olive stone bottom ash (OSBA) and paper sludge, reported compressive strengths of 18–43 MPa and phosphate removal efficiencies of up to 98%. Porous biochar-based geopolymers exhibited thermal conductivity as low as 0.107 W m⁻¹ K⁻¹. Although these findings demonstrate considerable potential, the reported performance varies with precursor chemistry, activator composition, curing regime, and testing conditions. Future research should prioritize standardized testing protocols, long-term durability evaluation, and pilot-scale implementation to facilitate industrial adoption.

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Dried fibres of Triumfetta cordifolia stem barks were modified by a non-thermal plasma discharge of the glidarc type and characterized by FT-IR, XRD, SEM, and pH_PZC. Studies on the influence of solution pH, adsorbent dosage, initial pollutant concentration, and adsorbent particle size on the adsorption of crystal violet (CV) and ibuprofen (Ibu) were performed. The results indicated that the plasma-modified biomass outperformed significantly better than the unmodified biomass-derived adsorbents. The kinetics and isotherms of the adsorption process using pristine and plasma-modified fibres were quantified and modeled. The kinetic curves showed a good fit to the pseudo-second order model and Elovich model for CV and Ibu adsorption, respectively, with equilibrium reached after 60 min. The ideal plasma-modified adsorbent ECM exhibited maximum adsorption capacity of 15.90 mg/g for CV and 90.36 mg/g toward Ibu.The Liu isotherm model was found to be the best fit to the experimental data and, its equilibrium constant was used to determine the adsorption thermodynamic parameters for both pollutants. The determined parameters, including enthalpy change (ΔH° < 0), entropy change (ΔS°>0), and Gibbs free energies change (ΔG° < 0) suggested an exothermic, random, and spontaneous nature of the adsorption process in the temperature range of 298–323 K. Kinetic models and thermodynamic studies suggested multilayer exposure with both physical and chemical forces simultaneously controlling the adsorption of CV and Ibu on the ECM adsorbent. Also, the revival test of the CV- or Ibu-laden adsorbent unveiled a high desorption efficiency up to four adsorption–desorption cycles.

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