Biofuels Bioproducts & Biorefining-Biofpr最新文献

Cassava residues consist mainly of stems generated during harvest and peels produced during root processing. The stem is a lignocellulosic biomass, and the peel is rich in starch; both can serve as alternative carbohydrate sources for bioethanol production. Two central composite design (CCD) experiments were conducted in this study. In the first, cassava stem underwent sequential acid and alkali pretreatment to enhance cellulose accessibility. The aim was to optimize solid loading (SL) and protein loading (PL) for enzymatic hydrolysis to maximize glucose concentration (GC) and hydrolysis yield (HY). Optimal conditions of 174.44 g L⁻¹ cellulose and 25 mg protein g⁻¹ yielded a GC of 116.89 ± 2.33 g L⁻¹ and an HY of 80.19 ± 1.61%. The second CCD optimized the enzymatic hydrolysis of cassava peel. Optimal parameters were 500 g L⁻¹ solids, 40 μL g⁻¹ solid α-amylase enzyme loading (AEL), and 30.7 μL g⁻¹ solid glucoamylase enzyme loading (GEL), resulting in a GC of 211.60 ± 5.74 g L⁻¹ and an HY of 61.10 ± 1.66%. Fermentation of the combined hydrolysates from cassava stem and peel produced an ethanol concentration of 103.74 g L⁻¹, with a process efficiency of 92.2% and a volumetric productivity of 2.21 g L⁻¹ h⁻¹.

Grape by-products, particularly seeds, are of great interest owing to their content of phenolic compounds, which offer significant health benefits. Traditional organic solvents used for phenolic extraction can be toxic and are highly flammable, raising environmental concerns. In contrast, natural deep eutectic solvents (NADES) present a greener alternative, as they are formed through hydrogen bonding between donors like sugars, amines, carboxylic acids, amino acids or alcohols, and acceptors like quaternary amines. The number and strength of these hydrogen bonds influence the physicochemical properties of NADES, and these in turn influence the extraction efficiency and selectivity of phenolic compounds. This study aimed at understanding how the physicochemical properties of NADES, particularly polarity, viscosity, conductivity and pH, affected the extraction efficiency of phenolic compounds from grape seeds, their antioxidant activity and the selectivity toward reducing sugars, compared with a hydroalcoholic solvent. NADES with different physicochemical properties were chosen, namely choline chloride with 1,2-propanediol, urea or malic acid, and at varying water contents (25, 50 and 75% w/w). The highest extraction efficiencies were obtained with 1,2-propanediol (TPC 5.13% DW) and malic acid (TPC 5.11% DW) at 50% water. Polarity was found to be a key property as matching the polarity of NADES to that of the target molecules led to improved extraction efficiency. In the case of malic acid, a combination of polarity and acidic pH led to high phenolics extraction efficiency and selectivity.

The widespread generation of solid agricultural waste has become a significant concern due to improper disposal practices such as open dumping and burning, which contribute to environmental pollution. Globally, over 5 billion tonnes of agricultural biomass waste are produced annually, highlighting the need for sustainable valorization strategies. Lignocellulosic biomass offers a promising feedstock for bioenergy and value-added products, given its environmental benefits, abundance, local availability, and potential to replace fossil fuels. This review explores both the fundamentals and recent advances in thermochemical conversion processes for biomass valorization. Key topics include process principles, mechanisms, and operating conditions. Major thermochemical techniques – torrefaction, combustion, pyrolysis, gasification, and liquefaction – are examined with emphasis on their applications and environmental advantages. The integration of these processes with renewable energy technologies is also discussed, offering opportunities to enhance efficiency and reduce environmental impact. Economic considerations, process integration, and optimization are reviewed to assess feasibility and scalability. This work provides a comprehensive overview of the technical, environmental, and economic dimensions of thermochemical biomass conversion, serving as a valuable resource for emerging researchers in the field.

Natural resources are considered as a promising and reliable source of energy to use in Palestine, especially in Gaza Strip, which has a great lack of infrastructure and energy resources needed to meet the energy demand. Recently, this issue has gained more interest because of the increase in the electricity resources. This study focuses on a technical and economic analysis for a potential energy method for the generation of methane gas (waste-to-energy, WTE). It mainly focuses on taking Gaza Strip as case study. Four different WTE methods were investigated and analyzed from technical and economic viewpoints in order to determine the best-case study to use in Gaza. The results underscore the significant potential of WTE technologies as a viable solution to alleviate energy shortages in Gaza. Incineration emerged as the most effective method for daily energy generation, producing approximately 565.554 MWh per day, followed by gasification, which generates around 291.176 MWh daily. A combined approach of incinerating combustible waste and using anaerobic digestion for organic waste could yield up to 800.853 MWh per day, offering a promising path to meeting the region’s energy needs. The recommendations for WTE adoption are provided for policymakers for implementation of appropriate WTE technology considering the highlighted technical, environmental and economic issues to ensure energy security in Gaza, Palestine.

The study optimizes and extends the extraction of polyphenols from by-products of the walnut from Nerpio (Juglans regia L.), thereby addressing the underutilization of agricultural waste and contributing to the development of a circular economy model. The by-products, including walnut shell and walnut tree pruning, were processed to extract high added value polyphenols. The optimal laboratory conditions were an ethanol solution with an alcohol strength of 60°, a solid/solvent ratio of 1:4, a particle size of 6 mm, a temperature of 25 °C and an extraction time of 1.5 h. The scalability of the process was validated on a semi-industrial scale, resulting in a 35.4 and 23.3% extraction yield for walnut shell and winter pruning, respectively. Extraction yields at a semi-industrial scale were higher than those obtained in the laboratory. The extracted polyphenols included ellagic acid, gallic acid and flavonoids, which have antioxidant, antimicrobial, anticarcinogenic, antimutagenic and cardioprotective activities. The process demonstrated technical feasibility, with potential applications in biomedicine, cosmetics and the food industry. This method enhances the value of walnut by-products from Nerpio, increasing their market value while promoting sustainable agricultural practices.

Ginkgo biloba trees are widely planted in urban areas of developed countries for their resilience, longevity and aesthetic appeal. Annual pruning to control tree size, shape and interference with traffic and pedestrians generates large volumes of unutilized Ginkgo biomass. This study aimed to valorize these pruning residues into charcoal by optimizing pyrolysis conditions and evaluating its fuel properties. The pyrolysis experiment was conducted at 400–600°C, after oven drying pretreatment. The mass yield of charcoal was found to vary from 27.33 to 32.05% and the approximate volume shrinkage was found to be 41.19–49.97%. The fuel properties of the charcoals were evaluated using the moisture absorption test, proximate and ultimate analysis, thermogravimetry, calorimetry and inductively coupled plasma optical emission spectrometry. The calorific value improved from 20.76 to 34.26 MJ kg⁻¹ with energy yield up to 46.75%. Charcoal exhibited superior thermal stability and better combustion performance. The results revealed satisfactory properties compared with other biomass, coal and biochar standards. The product complied with first-grade standards at 550 and 600°C and second-grade wood charcoal standards at other temperatures. However, higher concentrations of some heavy metals like Zn indicate the need for pretreatment and further research on co-pyrolysis for resource optimization. This study highlights the dual benefits of waste management and renewable energy, providing insights for urban planning and policymaking.

5-Hydroxymethylfurfural (HMF) is a key platform chemical derived from biomass glucose. Efficient glucose-to-HMF conversion requires both Lewis acid (LA) and Brønsted acid (BA) catalysis. However, the rigid structures of LA and BA in most heterogeneous metal oxides limit their cooperative catalytic performance. In this study, we synthesized sulfonated zirconia-layered SBA-15 featuring LA sites and flexible BA groups. The structure and acid properties were characterized by solid-state nuclear magnetic resonance (NMR) spectroscopy and trimethylphosphine probe analysis. The catalyst achieved a 261% increase in HMF yield in comparison with sulfated zirconia-layered SBA-15 containing only rigid LA and BA sites. Density functional theory (DFT) calculations reveal that the flexibility of the propyl sulfonic acid group enhances its synergistic interaction with LA, leading to a reduced energy barrier for the reaction.

Furans are among the most important compounds derived from biomass, providing conversion pathways for sustainable alternatives to petroleum-based fuels and materials. Furfural, 5-hydroxymethylfurfural (5-HMF), and 5-methylfurfural (5-MF) are furans that can be obtained by carbohydrate dehydration under acidic conditions at elevated temperature and pressure. One of the mechanisms to produce these compounds from lignocellulosic materials relies on prior fractionation of biomass carbohydrates and further dehydration catalysis. However, this is a costly and technically challenging method and it would be advantageous to develop a one-pot conversion mechanism that facilitates simultaneous biomass fractionation and conversion to furans. Ulva lactuca is an alga that has the advantage of being lignin-free and rich in glucose, rhamnose, and xylose, which are ideal for producing 5-HMF, 5-MF, and furfural, respectively. The high diversity of sugar constituents is also relevant for the production of added-value oligosaccharides. Catalysis with inorganic salts has been reported as a successful tool for biomass upgrading to furans when combined with hydrothermal pretreatments, and could provide a cheap and environmentally friendly one-step methodology for furan production. This study therefore aimed to investigate the effect of hydrothermal and dilute acid pretreatments, as well as treatment with inorganic salt solutions (ferric chloride, ferric nitrate, and aluminium nitrate) on U. lactuca biomass to produce oligosaccharides, monosaccharides, and furans (furfural, 5-HMF, and 5-MF). These methods resulted in a maximum sugar solubilization of 65% in non-salt-assisted hydrothermal pretreatments and 84% in salt-assisted hydrothermal pretreatments, with inorganic salt catalysis also resulting in 100% xylose, 36% glucose, and 46% rhamnose conversion to the respective furans.

Acid functionalized nitrides, including sulfonic-functionalized graphitic carbon nitride (SGCN) and sulfonic-functionalized boron nitride (SBN), were synthesized and used successfully in the microwave-assisted conversion of furfuryl alcohol (FA) into alkyl levulinates. Catalytic materials were characterized for their structural, morphological, and acid properties as well as for the synthesis of methyl levulinate (ML), chosen as model reaction. Reaction conditions, including temperature, time, and amount of catalyst, were optimized under microwave irradiation and pointed to SGCN providing optimum catalytic performance. At 140 °C, FA was fully converted in just 2 min, yielding ML in almost quantitative selectivity (98%). Additional experiments carried out by changing the catalyst/substrate ratio, proved the suitability of SGCN towards process intensification. Finally, a substrate scope evaluation demonstrated that various alcohols – ethanol, butanol, and isopropanol – were equally effective for synthesizing the corresponding alkyl levulinates, achieving 99% selectivity at 60% to 99% conversion.

This study explores the application of a mixed microalgae species for the removal of methylene blue dye from aqueous solutions, to enhance biosorption efficiency and economic viability. Algae biomass was chemically modified using calcium chloride, 1-butanol, sodium alginate and algae ash, each improving adsorption performance to varying degrees. Among these, calcium chloride-modified biomass exhibited the highest dye removal efficiency at 95%. Both wet and dry biomass were evaluated, with wet biomass achieving 89% and dry biomass 84% removal. Structural characterizations (X-ray diffraction, Fourier transform infrared, scanning electron microscopy, Brunauer–Emmett–Teller) confirmed the increased surface area and active site availability following modification. Kinetic modeling adhered to a pseudo-second-order model, while equilibrium data fit best with the Freundlich isotherm, indicating multilayer adsorption. Optimal conditions were identified as 0.16 g/L adsorbent dosage, 180 min contact time, pH 6.9 and a temperature of 25°C. Notably, this is the first study to directly compare wet and dry microalgal biomass for dye removal. Despite slightly higher efficiency by wet biomass, the dry form was favored owing to its superior stability, storage convenience and industrial applicability. The reusability of modified dry biomass further underscores its potential as a sustainable, cost-effective solution for large-scale wastewater treatment.