BioEnergy Research最新文献

This work proposes the use of a novel non-magnetic SrFe/CaO catalyst derived from waste materials, which have not been reported for biodiesel production under microwave conditions. Also, it evaluates the interaction of multiple reaction factors through statistical modeling. While CaO has been widely used in biodiesel production, its leaching and limited stability have motivated the search for improved materials. Hence, the Sr/CaO, Fe/CaO, and SrFe/CaO catalysts were synthesized by incipient impregnation of the calcined eggshells with Sr and Fe salts, followed by calcination at 800 °C. N₂-physisorption, XRD, and Hammett indicators were used as characterization techniques of the catalysts, and the reaction was performed in a batch reactor under microwave irradiation at 60 °C. The SrFe/CaO catalyst exhibited the highest basicity (60 mmol g⁻¹), possibly due to the formation of the α-Fe₂O₃ phase, and achieved a biodiesel yield of 92%. Further optimization using the Box-Behnken response surface methodology revealed that reaction time and the methanol-to-oil ratio significantly affected the yield, while microwave power had a minor influence. The optimal conditions for this system were 56 min, 150 W, and a methanol-to-oil ratio of 10:1, which resulted in a maximum biodiesel yield of 98.87%. Despite the promising activity, catalyst stability decreased over reuse cycles, likely due to CaO leaching.

This study optimized syngas production from Eucalyptus sp. wood chips in a pilot-scale downdraft gasifier through physical modifications (a barrier in the reduction zone) and low-cost catalysts (iron ore and nickel oxide), aiming to enhance gas quality and process efficiency for decentralized bioenergy systems. CFD simulations guided barrier design, increasing gas residence time by 50% (from 4.6 to 6.9 s) and Reynolds number in the reduction zone to > 280, enhancing turbulence. Experimental results showed that the iron ore catalyst boosted hydrogen content to 10.0 vol%, while the nickel catalyst achieved an optimal H₂/CO ratio of 2.3:1 for syngas applications. Combined use of both catalysts with steam further elevated the H₂/CO ratio to 4.19:1. Despite a minor reduction in lower heating value (LHV) from 4.07 to 3.95 MJ/Nm³, the barrier improved operational stability, reducing temperature fluctuations by 100 °C. Cold gas efficiency reached 54.7% for steam-assisted gasification. These results demonstrate the potential of low-cost modifications to enhance gasifier performance.

Monitoring charcoal quality is essential for the industry. Near-infrared (NIR) spectroscopy enables fast and accurate predictions of key properties. This study evaluated the use of benchtop and portable NIR sensors to predict charcoal characteristics from woody biomass of 15 commercial clones (11 Eucalyptus and 4 Corymbia). Two trees per clone were sampled at six stem positions, generating 30 composite wood samples. After carbonization and grinding, spectral data were collected, totaling 600 spectra per sensor. Partial least squares regression was used to develop models for gravimetric yield (GY), apparent relative density (ARD), fines content (FC), volatile matter content (VMC), ash content (AC), and fixed carbon content (FCC). For Eucalyptus clones, the benchtop sensor outperformed the portable one for GY (R²p = 0.74; RPD = 2.02), ARD (R²p = 0.87; RPD = 2.82), VMC (R²p = 0.72; RPD = 1.92), AC (R²p = 0.72; RPD = 1.92), and FCC (R²p = 0.63; RPD = 1.64). The portable sensor was better only for FC (R²p = 0.64; RPD = 1.60). Similarly, for Corymbia clones, the benchtop sensor performed better for GY (R²p = 0.79; RPD = 2.15), ARD (R²p = 0.87; RPD = 2.77), FC (R²p = 0.69; RPD = 1.73), and AC (R²p = 0.61; RPD = 1.62). The portable sensor showed better results for FCC (R²p = 0.61; RPD = 1.48) and VMC (R²p = 0.64; RPD = 1.40). Overall, benchtop and portable NIR spectrometers showed similar performance in estimating charcoal parameters.

Biogas is a promising renewable energy source that is produced by anaerobic digestion of organic waste and is mainly made up of carbon dioxide (CO₂) and methane (CH₄). However, its direct application is limited due to the presence of impurities such as CO₂, hydrogen sulfide (H₂S), water vapor, and trace gases (hydrogen sulfide, hydrogen, ammonia, nitrogen, oxygen, siloxanes, and carbon monoxide) that reduce its calorific value and cause operational issues. Their presence is undesirable since it lowers the calorific value of biogas and causes a number of issues with machine performance. Therefore, throughout the process of converting biogas into biomethane, multi-stage technologies for their removal are employed. This review provides a comprehensive overview of recent advances and future directions in biogas-upgrading technologies. Conventional physicochemical methods such as water scrubbing, chemical absorption, pressure swing adsorption (PSA), membrane separation, and cryogenic techniques are critically discussed with respect to efficiency, energy consumption, operational complexity, and cost. Furthermore, emerging biological upgrading technologies, including in situ and ex situ hydrogenotrophic methanation, and microalgae-based CO₂ fixation have been highlighted. These biological methods offer eco-friendly and cost-effective alternatives by converting CO₂ into CH₄ under mild conditions, although their scalability and integration into existing infrastructure remain under exploration. The review highlights technological challenges, comparative performances, and research gaps, offering insights into integrated and hybrid approaches that combine physicochemical and biological pathways for optimal biogas purification. This work serves as a reference for researchers and practitioners seeking sustainable and efficient biogas-upgrading solutions for grid injection, transportation fuel, and decentralized energy systems. The readers will learn about the scientific and technological obstacles to biogas technology advancement from this review.

The worldwide demand for renewable energy alternatives with agricultural stubble has driven the advancement of second-generation (2G) biofuels. Despite the abundance of stubble, it remains underexploited due to the complexity of plant cell walls, posing a noteworthy challenge to efficient biotransformation. The review explores recent advancements in extremophilic glycoside hydrolases (GHs) as promising biocatalysts to overcome biomass complexity. The study analyses recent innovations revealing how these robust enzymes, integrated with computational and biotechnology tools, unlock new ways to convert agricultural waste into bioenergy. The novel interdisciplinary convergence of microbiology, protein engineering, and artificial intelligence is highlighted for emerging innovations in enzyme design and formulation. Furthermore, recently discovered lytic polysaccharide monooxygenases (LPMOs) with GHs in enzyme cocktails synergistically enhance saccharification, facilitating the breakdown of complex polysaccharides. This synergy, combined with innovations in advanced recombinant DNA technology, synthetic biology, machine learning, and artificial intelligence, offers novel strategies for designing robust enzyme cocktails. Computational analysis of extremophilic endoglucanases identified conserved glycine, proline, and tryptophan residues as key contributors to structural integrity and catalysis in extreme environments. The review identifies emerging business opportunities in enzyme-based biomass valorization and outlines prospective directions for future research, including challenges in enzyme stability, process scalability, and integration into biorefineries.

Renewable diesel is a biofuel produced via hydro-processing of glycerides and fatty acids, offering a molecular structure closely resembling that of fossil diesel. This characteristic makes it a promising alternative for partially replacing conventional fuels, as it can be blended with petroleum diesel in high concentrations or used directly in compression ignition engines without modification. In this study, the effects of blending renewable diesel derived from fatty acids obtained from waste chicken fat with petroleum diesel were evaluated by analyzing their physicochemical properties according to ASTM D975 and EN 590 standards. The renewable diesel production involved two key stages: (1) hydrolyzing chicken fat waste at 250 °C for 120 min, achieving a 95% conversion to fatty acids, and (2) catalytic deoxygenation of the fatty acids using a sulfurized NiMo/Al₂O₃ catalyst, yielding 92% n-alkanes with 99% purity. The hydrolysis step was aimed at decreasing the amount of hydrogen in the hydrotreating step. The resulting biofuel blends exhibited excellent quality, with key parameters meeting regulatory standards: kinematic viscosity of 3.18 cSt, cetane index of 79.30, flash point of 109 °C, contamination < 1 ppm, and a filter blocking tendency of 1.03. Additionally, the cold flow properties were within acceptable ranges, demonstrating the suitability of these blends for commercial diesel applications. This study highlights the potential of utilizing waste chicken fat as a sustainable feedstock for high-quality renewable diesel production, contributing to the development of cleaner fuel alternatives.

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Bamboo appears as a highly promising and sustainable resource for sustainable activated carbon production because it grows fast and is abundantly available in nature while offering various environmental benefits. Bamboo is one among the fastest-growing plants, reaching maturity in 3 to 5 years; it can even successfully grow on degraded or marginal lands to prevent competition against food crops and help in soil restoration. The bamboo biomass can be processed into an array of energy forms, including solid fuels like charcoal, liquid fuels like bioethanol, and gaseous fuels like biogas and syngas, through thermochemical and biochemical conversion processes. Especially activated carbon from bamboo, which is prepared through controlled pyrolysis and activation processes, is highly expected to have some potential uses for water purification, air filtration, energy storage, and soil amendment. Bamboo cultivation, apart from its environmental considerations, also farms rural livelihoods and creates energy independence locally in developing areas. Sustainability in bamboo usage is hindered by factors such as ecological implications of massive monoculture bamboo plantations, variable maturity cycles of numerous species, and the considerable necessity of finding efficient supply chains and harvesting methods. These barriers are being overcome by means of technology. Technological advancement is steadily addressing these barriers in the form of improved pyrolysis and gasification units, integration of biochar production, and research on high-performance bamboo-derived carbon for batteries and electronics, all of which widen the application base of bamboo-based activated carbon. Nevertheless, to realize bamboo’s enormous potential requires policy support, market development, and continued investment in infrastructure and innovation. The present work gives an overview of bamboo and its wide application base especially as an energy resource, along with a discussion on activated carbon and biomass-based activated carbon uses. Bamboo-based activated carbon (BBAC) can act as replacement of conventional activated carbons which is depicted through its variable utilisation in the field of adsorption, water treatment and air filtration. New applications of BBAC in the field of energy storage (supercapacitors and batteries) exhibiting good electrochemical performances are also discussed. The goal should be to focus on interdisciplinary research and community involvement so that scalable solutions are devised to counter logistical, ecological and processing challenges.

This study provides a technological demonstration of enhanced production of monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA) and eicosapentaenoic acid (EPA) from a novel marine microalgae Tetraselmis astigmatica through the phosphorus (P) adjustment strategy. The microalga was isolated from the coast of the Bay of Bengal and was genetically identified through 18S rRNA sequencing. This microalga was grown in different concentrations (1, 5, 10, 20, 30 mg/L) of phosphorus. The highest biomass yield (347.0 mg/L) and biomass productivity (21.7 mg/L/day) were achieved at 30 mg/L, while the maximum lipid yield (105.8 mg/L) and productivity (6.6 mg/L/day) were attained at 10 mg/L phosphorus concentration. Analysis of the fatty acid profile revealed that the microalgae produce a maximum of 9.8% of EPA (ω-3 PUFA), an essential fatty acid for human health, in the higher (30 mg/L) P-supplemented condition. Further, the MUFA content was significantly enhanced (78%) by P-limitation (1 mg/L) with respect to the repletion (30 mg/L), whereas PUFA content was enhanced (21%) by P-supplementation (30 mg/L) with respect to the phosphorus-limited (1 mg/L) condition. The biodiesel produced under P-limitation (1 mg/L) had a higher level of saturated fatty acids (SFAs), resulting in better quality (improved cetane number, iodine value) compared to biodiesel produced under P-supplemented conditions. This P-adjustment strategy provides a targeted approach by using a phosphorus-limited condition (1 mg/L) for selective enrichment of MUFA and SFA fractions in the biomass of Tetraselmis astigmatica (for biodiesel production) and by using a P-supplemented condition (10 mg/L) for enrichment of the PUFA fraction (for food application).

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The increasing demand for stable biocatalysts in lignocellulose hydrolysis highlights the potential of onsite-produced fungal enzyme cocktails. Immobilization of these enzymes can improve their stability, enable reusability, and reduce costs, making them a viable option for sustainable industrial processes. The present study explored the direct encapsulation of the partially purified cellulase obtained from Trichoderma harzianum BPGF1 with polyvinyl alcohol (PVA) into nanofibers through electrospinning. The optimized solution composition for membrane synthesis was determined to be 13% (w/v) PVA and 25% (v/v) of the enzyme. The scanning electron microscopy confirmed the encapsulated enzymes in the nanofiber. The wettability of the electrospun enzyme nanofiber (ENF) was found to be 37.78°, which indicates the hydrophilicity. Young’s modulus of ENF was found to be 28.39 MPa, indicating reliable tensile strength. The effects of pH and temperature were studied on the ENF, and the maximum enzyme activity was observed at pH 7.0 and 70 °C, respectively, when compared with the free enzyme. The kinetic parameters were determined using Michaelis–Menten kinetics. The ENF was tested in the hydrolysis of pretreated Cynodon dactylon grass into fermentable sugars to produce biofuels. The ENF retained 50% of its initial enzyme activity even after 20 cycles, promising its application in continuous hydrolysis.

The fractionation of lignocellulosic biomasses has been widely reported as a way to establish biorefineries. However, more efforts are needed to valorize lignin and its phenolic derivatives in the production chain. Thus, the present study investigated the production of hydroxycinnamic acid esters and monosaccharides from an integrated scheme using corncob as raw material. After alkaline pretreatment, p-coumaric acid and ferulic acid were released in the liquid fraction (1.91 and 0.81 mg/mL), and they were isolated/concentrated in an aqueous two-phase system (ATPS) ethanol/ammonium sulfate. The best ATPS led to a high recovery in the top phase, corresponding to 89.7% for p-coumaric acid and 90.5% for ferulic acid. Direct esterification of the ATPS top phase with 20% (v/v) sulfuric acid guaranteed 1.60 mg/mL ethyl p-coumarate and 0.67 mg/mL ethyl ferulate, both products with potential application in cosmetics. Xylan was recovered in the ATPS and was successfully converted into xylose via acid hydrolysis (yield of 69% under 10% solids). The pretreated corncob was digested to obtain 99.6 g/L glucose under 30% solids in fed-batch mode using cellulase loading of 5 FPU/g and 2% (w/w) Tween 80. These results are in line with the idea of ​​comprehensive use of lignocellulosic biomass, especially in the development of lignin-derived products with high added value.