Biomass Resources Research Articles

Catalytic Conversion of Ethyl Levulinate to γ-Valerolactone Under Mild Conditions over Zr-Beta Acidic Zeolite Prepared by Hydrothermal Method

As an important biomass resource, γ-valerolactone (GVL) shows considerable potential for applications in biofuel production, organic synthesis, polymer, and food industries. Herein, an effective method was presented for synthesizing GVL through the catalytic transfer hydrogenation (CTH) of ethyl levulinate (EL) under mild conditions. Using isopropanol as a hydrogen donor, a 100% conversion of ethyl levulinate and an 88.7% yield of GVL were achieved over 2%Zr-Beta-7d catalyst at 110 °C for 8 h. The acidic sites of synthesized Zr-Beta via hydrothermal methods easily adjusted and offered high catalytic activity and selectivity. The Lewis (L) acid sites on the zeolite serve as the active centers for the conversion of EL. Characterization results indicate that the amounts of L acid sites on Zr-Beta increased with the Zr content and crystallization time rose, thus enhancing the selectivity for GVL. Additionally, the influences of catalyst dosage, reaction temperature, and time on catalytic performance are studied, as well as calculations of kinetic parameters such as reaction rate constants and activation energies. The 2%Zr-Beta-7d catalyst retains its high performance after five cycles. The current research may present an efficient approach for the conversion of EL to GVL under mild conditions.

Low-Temperature Borylation of C(sp3)-O Bonds of Alkyl Ethers by Gold-Metal Oxide Cooperative Catalysis.

Since ether moieties are often found not only in petrochemical products but also in natural organic molecules, the development of methods for manipulating C-O bonds of ethers is important for expanding the range of compound libraries synthesized from biomass resources, which should contribute to the goal of carbon neutrality. We report herein that gold nanoparticles supported on Lewis acidic metal oxides, namely α-Fe2O3, showed excellent catalytic activity for the reaction of dialkyl ethers and diborons, which enables the conversion of unactivated C(sp3)-O bonds to C(sp3)-B bonds at around room temperature. Various acyclic and cyclic ethers as well as a series of diborons participated in the heterogeneous gold-catalyzed borylation of unactivated C(sp3)-O bonds, to give a series of alkylboronates in high yields. Mechanistic studies corroborated that the present borylation of C(sp3)-O bonds of dialkyl ethers proceeded at the interface between gold nanoparticles and Lewis acidic metal oxides. Furthermore, adsorption IR measurements supported the notion that strong Lewis acid sites were generated at the boron atom of diborons adsorbed at the interface between Lewis acidic metal oxides and gold nanoparticles, which enabled us to ensure that the cooperation of gold nanoparticles and Lewis acidic metal oxides was responsible for the efficient transformation of unactivated C(sp3)-O bonds in ethers under mild conditions. This novel reaction technology which is specific to heterogeneous catalysts enables the activation of stable C(sp3)-O bonds of oxygenated chemical feedstock, which is beneficial for the sustainable synthesis of value-added organoboron compounds.

Life cycle assessment and thermodynamic performance of biomass-based combined cogeneration

Abstract This study presents a thermodynamic and life cycle analysis of a biomass-based integrated energy system, comprising a biomass gasification cycle, a steam Rankine cycle, and an ammonia fluid Organic Rankine cycle. The primary objective of the system is to efficiently convert olive husk, a sustainable biomass source, into electricity and heating. The gasification process generates syngas, which fuels a gas turbine, producing high-temperature exhaust that drives a Rankine cycle. The thermodynamic analysis indicates that the overall system achieves an energy efficiency of 20.85% and an exergy efficiency of 11.70%. The Rankine cycle exhibits an energy efficiency of 23.91%, while the Organic Rankine cycle demonstrates a higher exergy efficiency of 68.87%. Parametric studies reveal that increasing the combustion chamber temperature significantly enhances system efficiency and output, with energy efficiency rising linearly as the temperature increases from 800 °C to 1000 °C. Additionally, the analysis emphasizes the importance of the compressor's compression ratio on system performance. A life cycle assessment conducted using the ReCiPe methodology evaluates the environmental impact of the system throughout its lifecycle, revealing critical insights into its sustainability. This comprehensive evaluation highlights the potential of utilizing agricultural waste, such as olive husk, to produce renewable energy, thereby supporting environmental sustainability and waste management goals. The findings underscore the viability of the proposed system for enhancing energy production while minimizing environmental impacts, making it a promising solution for renewable energy generation in regions with abundant biomass resources.

Efficient production of spermidine from Bacillus amyloliquefaciens by enhancing synthesis pathway, blocking degradation pathway and increasing precursor supply.

Spermidine has broad application potential in food, medicine and other fields. In this study, a novel Bacillus amyloliquefaciens cell factory was constructed for production of spermidine from renewable biomass resources. Firstly, the speB gene was found to be optimal for synthesis of spermidine, and the function of SpeB was explained by amino acid sequence analysis and molecular docking. By replacing the native promoter of the speEB operon with the P43, the synthesis of spermidine was significantly enhanced in B. amyloliquefaciens HSPM1-P43speEB. After knockout of the genes yobN and bltD associated with spermidine degradation, the spermidine titer of the strain HSPM2 was further improved to 115.96mg/L, increased by 108% compared to HSPM1-P43speEB. Subsequently, the titer of spermidine was further increased to 277.47mg/L through enhancing the supply of the precursor methionine by overexpression of speD. Finally, the renewable biomass resources, xylose and feather meal were optimized to produce spermidine, and the maximum titer is up to 588.10mg/L after optimization. In conclusion, an efficient spermidine producing B. amyloliquefaciens was constructed through combinatorial metabolic engineering strategies, and the sustainable production of spermidine was achieved using the biomass resources of xylose and feather meal.

Genome-wide identification of the bHLH transcription factor family and the regulatory roles of PbbHLH74 in response to drought stress in Phoebe bournei.

Phoebe species constitute a large portion of subtropical forestry, which are key players in biomass resources. However, abiotic stresses such as drought stress severely limit the growth and development of P. bournei, and even lead to its death. It has been shown that basic helix-loop-helix (bHLH) as the second largest transcription factor family plays essential roles in response to multiple stresses in plants. However, little information of bHLH family is available in P. bournei. In this study, 130 PbbHLHs were identified and classified into 24 subfamilies. Then, the bHLH domain, conserved motifs and gene structures, evolutionary patterns and protein structural features were probed. The expression levels of 17 PbbHLHs were differentially induced by PEG and ABA by RT-qPCR analysis, indicating that they may be involved in drought stress response. Characterization of the drought candidate gene PbbHLH74 showed that it was transcriptionally active and localized in the nucleus. Heterologous transformation of PbbHLH74 into yeast improved cellular tolerance to drought stress. Meanwhile, overexpression of PbbHLH74 in Arabidopsis showed higher seed germination, plant biomass and expression levels of stress-related genes under drought conditions. Through the hairy root technique, overexpression of PbbHLH74 in P. bournei improved drought tolerance by enhancing root development and expression levels of genes involved in ABA-dependent and ROS scavenging pathways. Moreover, PbbHLH74 might positively regulate the expression of PbPOD by Y1H and dual-luciferase reporter assays. Overall, these results elucidated the structure and evolution of the PbbHLH family, in which PbbHLH74 could be applied to molecular assisted breeding for drought tolerance in P. bournei.

NTB Province’s commitment to achieve net zero emission by 2050 through energy transition

Abstract West Nusa Tenggara Province (NTB), Indonesia, is on a dedicated path to achieve Net Zero Emissions (NZE) by 2050. This review evaluated the province’s current policies, strategies, and initiatives aimed at transitioning to renewable energy, enhancing energy efficiency, and reducing carbon emissions. NTB’s significant renewable energy potential—spanning hydro, solar, geothermal, wind, biomass, and waste resources—and the projects underway to harness these resources were examined. Key challenges included the impacts of climate change, economic constraints, and infrastructure limitations, posing significant hurdles to the province’s energy goals. However, opportunities such as international collaborations, innovative financing strategies, and the development of large-scale renewable energy projects provide a strong foundation for progress. NTB’s proactive approach highlighted the critical role of community and private sector involvement in driving the energy transition. The review concludes that NTB’s efforts not only set a benchmark for sustainable development in Indonesia but also offer valuable insights for other regions aiming to achieve similar goals.

Dim Lights, Bright Prospects: Purple Phototrophic Bacteria-Driven Industrial Wastewater Treatment for Biomass Resource Recovery at Low Light Intensities

Dim Lights, Bright Prospects: Purple Phototrophic Bacteria-Driven Industrial Wastewater Treatment for Biomass Resource Recovery at Low Light Intensities

Cyanobacterial hydrothermal carbonization carbon as photocatalyst for selective aerobic oxidation of cyclohexane

The exploration of catalyst preparation techniques that incorporate environmental-friendly methodologies has consistently been the focus of scientific inquiry within the field of green synthesis of oxygen-containing organic chemicals. Herein, a metal-free hydrothermal carbonation carbon (HTCC) has been prepared utilizing cyanobacterial biomass produced during a water bloom in a freshwater lake. The HTCC produced is capable of performing photocatalytic selective oxidation of cyclohexane to cyclohexanol and cyclohexanone (KA oil) under ambient conditions. The use of cyanobacterial biomass allows for the efficient preparation of HTCC, which exhibits a conversion rate of cyclohexane that is 4.1 times of HTCC prepared with alternative carbon sources (glucose). The selectivity to KA oil over the samples are almost 100%. Characterizations and analysis reveal that cyanobacteria can lead to self-doping of nitrogen and hydrophobicity of the resulting HTCC, while sulfuric acid etching endow it with more photoactive sp2 hybridized structure units that contribute to a higher photogenerated carrier separation efficiency. The suitable band structure enables the cyanobacterial HTCC to produce superoxide radicals to oxidize cyclohexane. These findings are of great significance for the development of eco-friendly photocatalysts and the utilization of biomass resources.

Supported Alloy Catalysts for Diversification of Biomass Resources

Supported Alloy Catalysts for Diversification of Biomass Resources

Enhanced butanol production through intracellular NADH regeneration in CdSe-C. Acetobutylicumg semi-photosynthetic biohybrid system

Current environmental challenges and energy crises highlight the urgent need for a transition in energy mix. In this study, an innovative semi-photosynthetic biohybrid system that combined light-activated cadmium selenide quantum dots (CdSe QDs) with engineered Gram-positive anaerobic bacteria, Clostridium acetobutylicumg (C. acetobutylicumg), was developed to enhance renewable butanol production. The results demonstrated that CdSe QDs could be biosynthesized intracellularly within C. acetobutylicumg through the introduction of glutathione pathway, without causing significant damage to bacteria. Furthermore, this system showed remarkable tolerance to butanol and weak acids. Under illumination, the biological synthesized CdSe QDs enabled C. acetobutylicumg to achieve a 45.5 % increase in NADH/NAD+ ratio compared to C. acetobutylicumg without CdSe QDs. When utilizing undetoxified rice straw hydrolysate in photo-fermentation, this system achieved a butanol titer of 14.82 g/L and a yield of 0.29 g/g. Overall, this work aims to effectively harness solar energy and biomass resources for sustainable clean biofuel production.

Economic and demonstrative pilot-scale harvesting of microalgae biomass via novel combined process of dissolved air flotation and screw-press filtration

Microalgae, a promising sustainable biomass resource, lacks sufficient research for pilot-scale processes despite available technologies. Harvesting methods also pose challenges for large-scale applications. To address this, the economically viable large-scale microalgae harvesting system is here presented. The design integrates dissolved air flotation (5 m3/h) and screw-press filtration (10 kg/h), minimizing energy consumption suitable for industrial processes. This system efficiently harvests chlorella sp. (up to 4.1 m3) with a biomass harvest efficiency of 93 % and a dewatering rate of 11.9 %. Compared to centrifugation, the multi-stage system improves energy efficiency by 60.5 % with 1.7 kWh/m3 of energy consumption. This innovative approach demonstrates the potential for large-scale microalgae biomass harvesting.

Efficient electrocatalysis conversion of glycerol to formate in alkaline solution by nickel (oxy)hydroxide supported cobalt nanoneedle arrays

Electrochemical oxidation of glycerol into value-added chemicals represents a sustainable approach for not only valorizing biomass resources but also improving the energy efficiency of electrolysis by replacing the kinetically sluggish oxidation of water at the anode. Here, we present a nickel (oxy)hydroxide supported cobalt nanoneedle arrays catalyst (CoNA-NiOH/NF-2) for effective oxidation of glycerol. The loaded Co(OH)2 forms more oxygen defects, increases the active sites, and enhances the performance of glycerol oxidation. The CoNA-NiOH/NF-2 catalyst significantly reduces energy consumption by achieving a current density of 10 mA cm−2 at a low voltage of 1.22 V vs. RHE, and 100 mA cm−2 at 1.42 V vs. RHE, which is approximately 240 mV lower than oxygen evolution reaction (OER). Additionally, the Faraday efficiency of formate generation reached 98 %. The growth of renewable energy sources will greatly benefit from this strategy, which calls for replacing anodic OER with biomass oxidation.

Advancing biorefineries with ultrasonically assisted ionic liquid-based delignification: Optimizing biomass processing for enhanced bio-based product yields

Encouraging sustainable business needs utilization of bio-based substrate for green manufacturing of chemicals and fuels to achieve sustainable development goals set by the United Nations. One of the abundantly available bio-based substrates is lignocellulosic (LC) biomass, which requires effective pretreatment to fractionate into its structural biocomponents to maximize biorefinery potential. This study addresses the use of an inexpensive ionic liquid (triethylammonium hydrogen sulfate) [T2220][HSO4] in an ultrasound-assisted process as an environmentally acceptable pretreatment method for the delignification of LC biomass, specifically rice straw (RS). Using ionic liquid (IL)-assisted (IL, acid-IL, and alkali-IL) pretreatment procedures, the effects of IL volume, sonication time, and temperature were methodically examined for RS delignification. To evaluate the compositional changes in pretreated and raw RS, instrumental analyses were carried out. The maximum rates of 47 %, 55 %, and 64 % for the only IL, acid-IL, and alkali-IL treatments demonstrated the effect of temperature, operating time, and IL concentration on the delignification efficiency. The alkali-IL pretreatment was noteworthy for achieving a 64 % delignification rate under optimum values of IL volume (8.65 mL), sonication time (123 min), and temperature (82 °C). Artificial neural networks (ANN) and response surface methodology (RSM) were used for process modeling and optimization. With an accuracy of 0.989 in correlation coefficient, the ANN model outperformed the RSM regression model regarding forecasting delignification performance. Biorefinery of renewable biomass resources ensures the sustainable supply of materials, chemicals, and fuels. The delignification and downstream product recovery technologies are major limiting factors in the commercialization of biomass processing. The suggested [T2220][HSO4]-based ultrasonic approach provides a viable way to boost biomass valorization efficiency, which in turn improves economical and sustainable biorefinery and aids in the shift to green bio-based production.

Cellulose Nanocrystal Composite Membrane Enhanced with In Situ Grown Metal-Organic Frameworks for Osmotic Energy Conversion.

Access to clean and renewable energy, osmotic energy from salinity gradient difference, for example, is central to the sustainability of human civilization. Despite numerous examples of nanofluidic membranes for osmotic energy conversion, one produced from abundant and renewable biomass resources remains largely unexplored. In this work, cotton-derived cellulose nanocrystals (CNCs) are employed to fabricate a membrane by self-assembly with polyvinyl alcohol (PVA) and subsequent in situ growth of metal-organic framework (MOF), UiO-66-(COOH)2, to provide an example. The composite membrane exhibits excellent mechanical strength and toughness due to the long chains and hydrogen bonding interactions of PVA. The incorporation of UiO-66-(COOH)2 endows the composite membrane with abundant nano- and subnano-sized ion transport channels, resulting in a 150% increase in ion conductance, while also providing superior cation selectivity through collaboration with the sulfated CNCs. The composite membrane with 27.4% MOF content can achieve an osmotic energy conversion performance of 5.10Wm-2 under a 50-fold KCl gradient condition and a monovalent cation selectivity of ≈16 for K+/Mg2+. This work presents a solution for harvesting renewable osmotic energy by constructing nanofluidic membranes using plentiful renewable biomass materials and a simple, low-emission fabrication procedure.

The role of long-term hydrogen storage in decarbonizing remote communities in Canada: An optimization framework with economic, environmental and social objectives

Many small Canadian communities lack access to electricity grids, relying instead on costly and polluting diesel generators, despite the local availability of renewable energies like solar and wind. The intermittent nature of these sources limits reliable power supply; thus, hydrogen is proposed as a cost-effective and eco-friendly long-term energy storage solution. However, it remains uncertain whether hydrogen storage can significantly contribute to a 100% renewable energy system (100RES), given the diverse characteristics of these communities. Additionally, the potential for fully renewable infrastructure to reduce costs, mitigate adverse environmental impacts, and enhance social impact is still unclear. A multi-period optimization model that balances economic, environmental, and social objectives to determine the optimal configuration of 100RESs for isolated communities is introduced and utilized to evaluate hydrogen as an energy storage solution to seasonal fluctuations. By identifying the best combinations of technologies tailored to local conditions and priorities, this study offers valuable insights for policymakers, supporting the transition to sustainable energy and achieving national climate goals. The results demonstrate that hydrogen could serve as an excellent long-term energy storage option to address energy shortages during the winter. Different combinations and sizes of energy generation and storage technologies are selected based on the characteristics of each community. For instance, a community in the northern territories with high wind speeds, low solar radiation, extremely low temperatures, and limited biomass resources should optimally rely on wind turbines to meet 80.7% of its total energy demand, resulting in a 62.0% cost reduction and a 49.5% decrease in environmental impact compared to the existing diesel-based system. By 2050, all communities are projected to reduce energy costs per capita, with northern territories achieving 33% and coastal areas achieving 55% cost reductions, eventually leading to the utilization of hydrogen as the main energy storage medium.

The Confinement Behavior and Mechanistic Insights of Organic Phase Change Material Encapsulated in Wood Morphology Genetic Nanostructures for Thermal Energy Storage.

Wood, a renewable and abundant biomass resource, holds substantial promise as an encapsulation matrix for thermal energy storage (TES) applications involving phase change materials (PCMs). However, practical implementations often reveal a disparity between observed and theoretical phase change enthalpy values of wood-derived composite PCMs (CPCMs). This study systematically explores the confinement behavior of organic PCMs encapsulated in a delignified balsa wood matrix with morphology genetic nanostructure, characterized by a specific surface area of 25.4 ± 1.1 m2/g and nanoscale pores averaging 2.2 nm. Detailed thermal performance evaluations uncover distinct phase change behaviors among various organic PCMs, influenced by the unique characteristics of functional groups and carbon chain lengths. The encapsulation mechanism is primarily dictated by host-guest interactions, which modulate PCM molecular mobility through hydrogen bonding and spatial constraints imposed by the hierarchical pore structure of the wood. Notably, results demonstrate a progressive enhancement of nanoconfinement effects, evidencing a transition from octadecane to stearic acid, further supported by density functional theory (DFT) calculations. This research significantly advances the understanding of nanoconfinement mechanisms in wood-derived matrices, paving the way for the development of high-performance, shape-stabilized composite PCMs that are essential for sustainable thermal energy storage solutions.

Biomass Electrocatalysts: Exploiting Haemoglobin-derived Fe Sites Supported by Waste-derived, S and N-enriched Carbon for Efficient Oxygen Electro-reduction

Abstract Biomass resources offer a diverse array of low-cost feedstocks having interesting functional properties for the manufacture of electrocatalysts for the energy sector. In this study, haemoglobin (Hb), lignin, tannic acid and urea were used to make high surface area N, S-codoped carbon electrodes rich in highly dispersed heme-like (Fe-Nx) sites. By pyrolyzing precursor mixtures containing un-purified Hb, lignin, tannic acid and urea, in appropriate mass ratios, a high surface-area S, N-codoped carbon nanostructured electrocatalyst was obtained. The electrocatalyst had surface pyridinic and pyrrolic species together with highly dispersed N-coordinated Fe sites. The developed FeSN/C electrocatalyst exhibited an ORR onset potential of 0.98 V vs. RHE in 0.1 M KOH, a half-wave potential of 0.87 V and a low Tafel slope of 54 mV/dec. This work encourages the design of biomass-derived electrocatalysts for ORR, in particular showing that haemoglobin in bovine blood is suitable for use as an iron source when making Fe-N-C electrocatalysts.

Toward economy hydrogenation: Highly efficient hydrodeoxygenation of guaiacol to cyclohexanol over a CoNi-NC catalyst

Lignin and other underutilized biomass resources have significant potential for producing specific chemicals through hydrogenation. However, current challenges in this field include not only the high cost of catalyst preparation but also the demanding reaction conditions required. In this study, a CoNi-NC alloy catalyst with high specific surface area and mesoporous structure was prepared by calcining Ni-doped ZIF-67 material. The Co3Ni1-NC catalyst achieved complete conversion of guaiacol with a cyclohexanol yield reaching 92.7 %, under conditions of 1.2 MPa H2 pressure and 180 °C reaction temperature. The study found that Co-Ni alloys possess superior hydrogen adsorption activation capability, which is a critical factor affecting the hydrogenation capacity of the catalyst. The prepared Co3Ni1-NC not only significantly reduces the H2 pressure and temperature for the guaiacol hydrodeoxygenation (HDO) reaction but also achieves high-efficiency conversion of guaiacol in water as the primary solvent. This undoubtedly saves costs and reduces environmental impact. The CoNi-NC catalyst also possesses magnetic properties, making it easy to fully recover. Related characterization and cycling experiments have demonstrated that the catalyst has excellent recyclability. These properties of the CoNi-NC catalyst will significantly enhance its economic viability. Furthermore, this catalyst exhibited excellent hydrogenation performance for lignin model compounds, providing a valuable reference for the application of alloy MOFs materials in the hydrogenation of lignin compounds.

Exploring the Sustainable Utilization of Deep Eutectic Solvents for Chitin Isolation from Diverse Sources.

Deep eutectic solvents (DES) represent an innovative and environmentally friendly approach for chitin isolation. Chitin is a natural nitrogenous polysaccharide, characterized by its abundance of amino and hydroxyl groups. The hydrogen bond network in DES can disrupt the crystalline structure of chitin, facilitating its isolation from bioresources by dissolving or degrading other components. DES are known for their low cost, natural chemical constituents, and recyclability. Natural deep eutectic solvents (NADES), a subclass of DES made from natural compounds, offer higher biocompatibility, biodegradability, and the lowest biotoxicity, making them highly promising for the production of eco-friendly chitin products. This review summarized studies on chitin isolation by DES, including reviews of biomass resources, isolation conditions (raw materials, DES compositions, solid-liquid ratios, temperature, and time), and the physicochemical properties of chitin products. Consequently, we have concluded that tailoring an appropriate DES-based process on the specific composition of the raw material can notably improve isolation efficiency. Acidic DES are particularly effective for extracting chitin from materials with high mineral content, such as crustacean bio-waste; for instance, the choline chloride-lactic acid DES achieved purity levels comparable to those of commercial chemical methods. By contrast, alkaline DES are better suited for chitin isolation from protein-rich sources, such as squid pens. DES facilitate calcium carbonate removal through H+ ion release and leverage unique hydrogen bonding interactions for efficient deproteination. Among these, potassium carbonate-glycerol DES have demonstrated optimal efficacy. Nonetheless, further comprehensive research is essential to evaluate the environmental impact, economic feasibility, and safety of DES application in chitin production.

Acid Resistance Engineering of Endoglucanase for the Degradation of Wine Lees.

Wine lees is a low value biomass resource rich in cellulose, with great potential for producing organic fertilizers and chemicals. However, the high acidity of wine lees limits the catalytic efficiency of the conversion tool endoglucanase. Here, we expressed endoglucanase tCel5A from Trichoderma reesei in Pichia pastoris, and the combination of promoter AOX1 and signal peptide SUC2 resulted in a highly active expression of 4632.81 U/mg. Subsequently, the catalytic center design and surface charge modification strategy resulted in mutants T88H/W255H and S45D/T55D/T59D exhibiting catalytic activity twice and three times higher than WT at pH 3.0, respectively. Finally, when the solid-liquid ratio was 1:15 (w/v), the degradation rate of wine lees was nearly double that of WT. The degradation products contained a variety of industrial and pharmaceutical raw components, including the antioxidant and anticonvulsant isopiperolein B. This study accelerates the green and sustainable management of wine lees.