The price of pure cellulase enzyme for the recovery of fermentable cellulosic sugars is one of the major challenges that limit the commercialization of second-generation biofuels and bio-based products. This work shows a means to greatly reduce the cost of cellulases. The abundant capacity of plants to synthesize and hyperaccumulate transgenic proteins in their plastids has been demonstrated for two gene constructs using either NPTII or TetC to regulate the expression of bacterial cellulase Cel6A. Previously, the expression of Cel6A to 20-35% of total soluble leaf protein in tobacco was shown in two consecutive field trials. Moving forward, the key challenge was the extraction of active enzymes from the transgenic tobacco leaves hyperaccumulating bacterial cellulases in a cost-effective manner. The study showed that unpurified crude extracts of NPTII and TetC transgenic tobacco leaves recovered similar to 23% and similar to 29% w/w cellulosic sugars from energycane bagasse, respectively. A supplementation of as low as 25% of purified commercial cellulase improved the glucose recovery by 2.9 times (similar to 85% w/w) compared to 100% crude extract, which is comparable to the glucose recovery obtained by commercial cellulases, thereby suggesting a reduced requirement of commercial cellulases leading to a cost reduction of 75% for biorefineries. Assuming a stable 40% cellulase yield in total soluble protein under field conditions and multiple harvests (one to three) a year, the study estimates that the potential cost for saccharification of 1 t of lignocellulosic biomass can be reduced to 67-200 USD by using crude leaf extracts of transgenic tobacco. (c) 2026 The Author(s). Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.
In this study, a green extraction strategy was developed for the recovery of antioxidant phenolics and flavonoids from Urtica dioica leaves using deep eutectic solvents (DESs). Seven DESs consisting of lactic acid (La) and ethylene glycol (Eg) at different molar ratios (1:1, 1:2, 2:1, 1:3, 3:1, 1:4, and 4:1) were prepared and screened based on the total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Principal component analysis (PCA) identified La:Eg (1:4) as the best-performing DES. The homogenizer-assisted extraction process using La:Eg (1:4) was subsequently optimized using a Box-Behnken design with four variables (solid mass, water content, homogenization speed, and extraction time). Bioactivity was evaluated using TPC, total flavonoid content (TFC), and antioxidant activity determined by DPPH and 2,2 '-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. In addition to modeling and experimental validation, PCA was applied to evaluate the relationships between the optimized extraction conditions and bioactivity indicators, including TPC, TFC, DPPH, and ABTS.
Oxidation of furfural (FF), a bio-based platform chemical, was investigated using a range of iron-, vanadium- and iron-zinc-oxalates supported on silica gel (FeVOx@silica and FeZnOx@silica, respectively) as precursor for FeV@silica and FeZn@silica oxide catalysts and H2O2 as a green oxidant. Furfural oxidation offers a route to valuable C4 diacids and lactones serve as monomers for biodegradable plastics, providing greener alternatives to petrochemicals. FeVOx@silica catalysts containing 5 wt% metal were synthesized following an oxalic-acid-assisted in situ impregnation/deposition method and calcined at 150-300 degrees C All catalysts developed magnetically recoverable properties owing to the presence of the iron oxide phases. Catalysts showed high activity in mild liquid-phase FF oxidation (70 degrees C, 1 atm), achieving nearly complete substrate conversion within 3-4 h. Gas chromatography indicated the formation of two main products: maleic anhydride and 2-furoic acid, with minor observed quantities of 2(5H)-furanone. The addition of a small amount of formic acid (5 vol%), despite having little effect on FF conversion, notably impacted product ratios. Incorporating Zn cations into the Fe-based catalyst (FeZn@silica) led to noticeable improvement of catalyst durability and suppression of the unproductive rapid decomposition of H2O2. FeZn catalyst calcined at 200 degrees C exhibited the highest product yield, whereas patterns obtained upon calcination below 150 degrees C and above 300 degrees C, despite furfural consumption (mineralization), produced much less detectable liquid products (suggesting Fenton-like overoxidation and/or strong adsorption). This work demonstrates an effective green oxidation process for furfural under mild conditions using Earth-abundant metal-based catalysts.
This study investigates the relationship between artificial intelligence (AI) development and biofuel production using a balanced panel dataset of 12 European Union (EU) countries over the 2008-2024 period. Employing feasible generalized least squares (FGLS) estimation with distributed lag specifications, the analysis controls for Renewable Energy Directive shocks and common cyclical effects through time fixed effects. The results reveal that AI-related scientific publication volume exerts a positive and statistically significant effect on biofuel production, with a cumulative elasticity of approximately 0.47 materializing predominantly through a 2-year lag, while venture capital investment in AI technologies generates a complementary but more modest effect (cumulative elasticity: 0.076) over a 1-year horizon. These findings suggest that AI influences biofuel production through two distinct yet complementary pathways: a research output channel and a commercial adoption channel, both of which are theoretically consistent with a multi-stage technology diffusion process. Quantile regression estimates further reveal pronounced asymmetry across the production distribution, with the AI effect being substantially stronger among low-production countries (Q10-Q25 elasticities: 0.58-0.61) and statistically insignificant among high-production countries, a pattern attributable to technological catch-up advantages, ceiling effects imposed by binding blending mandates, and disproportionate early-adopter gains. Mechanism analysis indicates that AI operates primarily through R&D absorption capacity, agricultural productivity improvements, and land resource optimization rather than through direct volumetric expansion. These findings carry implications for the integrated design of AI and biofuel support policies at both national and EU levels.
The immobilization of lipase B from Candida antarctica (CALB) on an amino-epoxy functionalized magnetic support (Fe3O4-PEI-DGEBA) resulted in a highly stable and efficient biocatalyst for biofuel production from tilapia oil. The synthesized support was characterized using scanning electron microscopy, transmission electron microscopy, X-ray fluorescence spectroscopy, Fourier transform infrared (FTIR), thermogravimetric analysis, and vibrating sample magnetometry, confirming the successful immobilization and preservation of the magnetic core. The immobilized CALB exhibited superior catalytic performance, achieving a 97% immobilization yield, remarkable thermal and pH stability, and retaining over 80% activity after 120 days of storage. Additionally, it maintained high esterification efficiency over 10 reuse cycles, demonstrating its industrial applicability. Molecular docking and molecular dynamics simulations revealed that immobilization enhanced CALB's substrate selectivity, favoring long-chain saturated fatty acids through hydrophobic interactions with residues such as Leu140, Ala141, and Val154. Hybrid molecular mechanics and quantum mechanics simulations identified the nucleophilic attack step as the rate-limiting stage of the esterification process, with an energy barrier of 17.5 kcal mol-1, aligning with the enzyme's optimized catalytic efficiency post-immobilization. The biodiesel produced 98.8% conversion efficiency, with key FTIR and nuclear magnetic resonance signals confirming successful esterification. However, its viscosity exceeded ASTM and ANP standards, suggesting the need for blending with lower-viscosity biofuels. These findings highlight Fe3O4-PEI-DGEBA@CALB as a promising biocatalyst for sustainable biofuel production, combining high stability, reusability, and efficiency, with potential applications in green chemistry and industrial biocatalysis.
One of the main challenges in drug delivery is to enhance the bioavailability of poorly water-soluble drugs using non-toxic nanocarriers such as hydrophilic polymer matrices. Polysaccharide aerogels, such as starch aerogels, are promising drug delivery matrices owing to their biocompatibility, biodegradability, abundant availability, and high surface area for drug loading. In this study, after the synthesis of potato starch aerogels as drug carriers, the characteristics of the prepared samples were investigated by Brunauer-Emmett-Teller (BET), scanning electron microscopy, Fourier transform infrared (FTIR), and X-ray diffraction (XRD) analyses. Starch aerogels were loaded with ibuprofen by adsorption from drug solution using different solvents of ethanol and isopropanol. The drug-loaded aerogels were analyzed by UV, FTIR, and XRD spectroscopy, confirming the drug's structural integrity after loading. Adsorption studies using ethanol and isopropanol revealed that ibuprofen's higher solubility in ethanol led to an approximately 9% increase in drug loading compared with isopropanol. Adsorption equilibrium studies show that the Freundlich model for both ethanol and isopropanol solvents shows a better curve fit with the experimental data, with correlation coefficients of 0.9764 and 0.984, respectively. Owing to the poor dissolution rate of pure ibuprofen, the dissolution rate is improved by loading the drug onto starch aerogel, such that after 240 min, 72 and 66% of the ibuprofen present on the carrier is dissolved when ethanol and isopropanol solvents are used, respectively. Then, the small-volume USP2 device used in this study was built using scaling-down rules, considering the standard USP2 as a design reference. For the first time, the particle image velocimetry (PIV) technique was used to investigate the flow patterns and their effects on the drug release. The instantaneous velocity data shows the presence of eddies and secondary flows in different regions of the tank, and also the dominant flow inside the tank is tangential flow created by the rotation of the blade. These flows are very suitable for micro-mixing. The results of the obtained data show that this drug delivery system can be used as an alternative to the micronization method, which is currently used to achieve rapid drug release.
Carotenoids from microalgae, including beta-carotene, lutein, and astaxanthin, have significant potential for food and healthcare applications due to their antioxidant properties. Increasing demand for these pigments necessitates greener extraction methods. Natural deep eutectic solvents (NADES) have emerged as promising green solvents that could replace conventional organic solvents. This study investigates the extraction and quantification of beta-carotene, lutein, and astaxanthin from Chlorella vulgaris and Spirulina subsalsa using a range of NADES to identify efficient, nontoxic solvent extraction methods suitable for functional food development. High-performance liquid chromatography (HPLC) was used for quantification. The lactic acid:1,2-propanediol (LAPo) system showed the highest extraction efficiency for carotenes in both species. beta-Carotene extraction reached 73% in C. vulgaris and 97.63% in S. subsalsa. Lutein extraction reached 61% in C. vulgaris and 98% in S. subsalsa. Astaxanthin extraction reached 36% in C. vulgaris and 43% in S. subsalsa. For S. subsalsa strain Z15, NADES performed comparably to traditional solvents. This research highlights the potential of NADES as eco-friendly alternatives for carotene extraction and supports their application in scalable functional food production. Gelatin matrices incorporating microalgal carotenoids were also developed to evaluate color stability and related properties.
Ucu & uacute;ba (Virola surinamensis) fat is an important income source for Amazonian communities. Local businesses typically process whole seeds for fat extraction; however, seed structural integrity may influence extraction efficiency and fat quality. This study evaluated the effect of seed shelling as a preprocessing strategy on lipid recovery from ucu & uacute;ba seeds. Fat samples extracted by pressing from whole (WUF) and shelled seeds (SUF) were characterized in terms of fatty acid composition, quality parameters (smoke point, acid value, free fatty acids, peroxide value, slip melting point, saponification value, unsaponifiable matter, iodine value), total phenolic content (TPC), antioxidant activity measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2 '-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, and thermal behavior measured by differential scanning calorimetry (DSC). Shelling increased fat yield, with SUF reaching 52.05% compared with 47.65% for WUF, thereby reducing residual press cake generation. Both samples presented similar quality and showed a predominance of saturated fatty acids, including myristic (72% to 73%) and lauric (17% to 18%). The WUF sample showed a higher TPC than SUF (6.54 and 5.82 mg GAE g-1, respectively), with correspondingly higher antioxidant activity, as determined by ABTS (4.26 mu mol TE g-1) and DPPH (12.25 mu mol TE g-1). Thermal analysis showed a distinct exothermic event during crystallization and a single endothermic peak upon melting. These results indicate that shelling enhances fat recovery but reduces phenolic content and antioxidant activity, potentially increasing operational costs. The compositional and thermal characteristics of ucu & uacute;ba fat suggest its suitability for cosmetic and therapeutic applications within Amazonian bioeconomy value chains.
This study integrates kinetic modeling in AQUASIM with SuperPro Designer (R) simulation to investigate the techno-economics of bioethanol production from microalgae. For the first time, kinetic models supported by SuperPro Designer (R) were developed for bioethanol production from enzymatic hydrolysis products of mixed microalgae. Comparative techno-economic evaluations were conducted on dry and wet processing routes for microalgae. Key economic indicators (net present value, internal rate of return [IRR], payback time) and variable sensitivities were investigated. The agreement of experimental and simulation results using SuperPro Designer (R) showed the highest reducing sugar yield with cellulase (50 degrees C, pH 5), alpha-amylase (70 degrees C, pH 6), at the optimal initial concentration of 50 g L-1. Simultaneous enzyme addition accelerates hydrolysis and improves process economics. The techno-economic analysis revealed that the wet biomass strategy, by removing harvesting, drying, and milling steps, reduced both CAPEX and OPEX by $1000 per batch. This modification also reduced the production cycle from 209.1 to 154.3 h. Sensitivity analysis found that +/- 5% changes in bioethanol price and +/- 10% shifts in annual throughput caused corresponding variations in IRR and payback time. Despite these changes, the wet biomass strategy consistently maintains an IRR above the economic threshold (10%). These findings underscore the superior economic viability of the wet biomass strategy for industrial bioethanol production.
This study investigates the hydrothermal conversion of inulin using potassium pyrosulfate to levulinic acid (LA). The Box-Behnken design approach was applied to optimize the conversion parameters and analyze the interactions influencing LA yield. Optimal LA yield was obtained at mid-range temperatures in combination with medium to high catalyst concentrations and reaction times. An LA yield of 35.69% was obtained under optimal conditions of 15.3% biomass loading, 1.2 M potassium pyrosulfate at 170 degrees C for 60 min. Concurrently, formic acid was obtained at a yield of 15.7%, whereas the formations of 5-hydroxymethylfurfural and fructose remained negligible, each yielding below 2%. These results indicate that when used as a feedstock with potassium pyrosulfate, inulin has considerable potential for the sustainable synthesis of high-value platform chemicals.
Biorefineries are central to the transition toward a circular bioeconomy; however, their increasing scale and technological heterogeneity, and the integration of biological, chemical, and thermochemical processes introduce complex challenges related to safety, sustainability, and operational reliability. Existing Safe-and-Sustainable-by-Design (SSbD) frameworks provide valuable guidance for chemicals and materials but offer limited operationalization for process-based biosystems, which are characterized by biological uncertainty, feedstock variability, and tightly coupled unit operations. This study proposes an integrated biobased SSbD (BioSSbD) framework specifically tailored to biorefineries, embedding safety, environmental sustainability, technoeconomic performance, and operational reliability into both early stage design and continuous improvement. The framework combines a layered safety concept with a Plan-Do-Check-Act (PDCA) cycle and an 11-step assessment methodology supported by nine safety-driven design components. It integrates established tools such as hazard identification and risk assessment, inherent safety principles, life cycle assessment (LCA), technoeconomic indicators, and total quality management. The BioSSbD framework is systematically compared with major SSbD approaches developed by European and international organizations - e.g., the European Commission (EC), the European Chemical Industry Council (CEFIC), the Organisation for Economic Co-operation and Development (OECD), and the World Business Council for Sustainable Development (WBCSD) - demonstrating its added value in addressing process-level risks, biological hazards, and operational dynamics specific to biorefineries. A literature-grounded conceptual application to a lignocellulosic bioethanol biorefinery illustrates how early integration of safety and sustainability considerations can guide design decisions, indicating literature-informed potential reductions of approximately 20% to 40% in relative process-risk indices and 15% to 20% in life cycle greenhouse-gas emissions under comparable process conditions. Overall, the proposed framework provides a structured, adaptive, and scalable approach for advancing safe and sustainable biorefinery development, supporting alignment with circular bioeconomy goals and emerging SSbD certification initiatives.
The prolonged start-up period of high-rate anaerobic anaerobic reactors represents a critical techno-economic bottleneck, and this study demonstrates that targeted bioadditive conditioning offers an effective strategy to accelerate granulation while simultaneously enhancing methane yields at laboratory and pilot scales in two 2 L lab-scale upflow anaerobic sludge blanket reactors (R1: multivalent cation addition, R2: chitosan addition) and subsequently, a 20 L pilot-scale reactor, respectively. Laboratory-scale experiments demonstrated that chitosan-based conditioning shortened granulation time by approximately 15 days compared with conventional operation, whereas multivalent cations primarily improved microbial diversity and structural stability. When these strategies were combined and evaluated in a 20 L pilot-scale reactor, biomass concentration increased by 126% and methane content reached 74.5% within 52 days, indicating accelerated commissioning and earlier energy recovery. The confirmation of this hypothesis is economically relevant, as reduced start-up periods directly translate into faster cash-flow generation, lower financial risk during early operation, and improved feasibility of capital-intensive anaerobic treatment facilities. Beyond process intensification, the results reveal an overlooked interdisciplinary connection between polymer-assisted microbial aggregation, granule-scale ecology, and reactor-scale techno-economic performance. Metagenomic analysis revealed that chitosan favored the dominance of extracellular polymeric substance-producing genera such as Methanobacterium and Clostridium, while multivalent ions supported greater microbial diversity. Overall, this work provides a scalable and cost-effective framework for improving anaerobic digester start-up performance, offering clear industrial relevance and a basis for future integration with digital twin-based optimization and investment decision-support tools. Last but not least, this study highlights the synergistic impact of bioadditives and reactor scale on anaerobic sludge granulation and system performance.
This study used thermogravimetric analysis to investigate kinetics and synergistic behavior during the co-pyrolysis of cotton stalk (CS), high-density polyethylene (HDPE), and their blends, which contained 50% to 90% CS. The experiments were performed under a N2 atmosphere at heating rates of 5, 10, and 20 degrees C min-1 over a temperature range of 30-800 degrees C. The CS thermograms show that it decomposed in three stages, whereas HDPE decomposed in a single step. The blends exhibited three-stage decomposition similar to CS. Model-free isoconversional methods, including the Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), and Starink methods, were used to estimate the apparent activation energy (E a). Pre-exponential factors were calculated using the Kissinger method for all feedstocks. The average E a values for CS were 163, 166, and 162 kJ mol-1, and for HDPE were 279, 276, and 277 kJ mol-1, using the KAS, FWO, and Starink methods, respectively. For the blend containing 10 wt% HDPE, the E a values were close to those of CS. Increasing the HDPE content from 20 to 50 wt% reduced the E a by approximately 9% to 19%. The lowest E a of 132 kJ mol-1 was obtained for the blend containing 50 wt% HDPE across all kinetic models. The co-pyrolysis experiments demonstrated that a synergistic effect exists between CS and HDPE during co-pyrolysis, suggesting that these blends have strong potential for the production of value-added chemicals.
The long-term viability of Jatropha curcas as a biodiesel feedstock has been widely debated. Many early initiatives failed to deliver consistent economic returns despite promising environmental attributes. This study re-evaluated J. curcas-based systems within an integrated environmental-economic framework, focusing on their potential role in postmining (industrial) land restoration rather than stand-alone biofuel production. A system-oriented analytical approach was used to examine how environmental rehabilitation requirements, cost structures, and risk-management mechanisms interact to influence technoeconomic performance. The results indicated that economic relevance does not arise primarily from yield optimization but from the integration of biomass production into mandatory land restoration processes, where environmental obligations enable cost internalization and long-term liability reduction. The findings show that J. curcas cultivation can be environmentally robust and economically viable when evaluated within integrated sustainability and investment frameworks. Shifting the evaluation logic from commodity profitability to system-level value creation provides a transferable framework for diverse postmining and postindustrial contexts worldwide.
Activated carbon was prepared from Chlorella by carbonization and potassium hydroxide activation, and its structural properties and methylene blue (MB) adsorption performance were evaluated. Raw Chlorella exhibited an adsorption capacity of 287.2 mg g-1, which decreased to 214.8 mg g-1 after carbonization. Potassium hydroxide (KOH) activation increased the adsorption capacity to 329.7 mg g-1, representing an increase of approximately 15% compared with the raw material and 54% relative to the biochar. This improvement was attributed to the development of a porous structure and the increase in specific surface area induced by the activation process. Adsorption isotherms were analyzed using the Langmuir, Freundlich, and Temkin models. The Langmuir model gave a maximum monolayer adsorption capacity of 379.6 mg g-1, whereas the Freundlich model provided the best fit (R 2 = 0.93), indicating predominance of multilayer physisorption. Temkin analysis showed strong adsorption during the initial stages, followed by a gradual decrease in adsorption heat, reflecting surface heterogeneity and a partial contribution of chemisorption. These findings demonstrate that KOH activation effectively enhances the adsorption performance of Chlorella-derived carbon materials and that the adsorption mechanism involves coexistence of monolayer adsorption, multilayer adsorption, and chemisorption.
This study reports the production of squalene and other value-added metabolites from crude glycerol by the yeast Pichia pastoris. To the best of our knowledge, this is the first study to demonstrate the utilization of crude glycerol for squalene biosynthesis in P. pastoris, with process intensification achieved through fed-batch cultivation in a bioreactor. A maximum squalene titer of 70 mg L-1 was achieved using 1% (v/v) crude glycerol along with 0.2 mg L-1 added terbinafine in mineral salt media. Various biokinetic models, modified-Gompertz, Luedeking-Piret, Aiba, and Andrews models, were applied to understand the kinetics of squalene accumulation by P. pastoris. The Modified-Gompertz model accurately predicted the maximum squalene production, whereas the Aiba and Andrews models described the inhibitory effect caused by crude glycerol. Scale-up experiments performed using a laboratory-scale stirred tank bioreactor demonstrated enhanced squalene accumulation by 1.67-fold under batch operation (117 mg L-1) and by up to 2.94-fold under fed-batch operation (206 mg L-1), relative to the shake flask cultivation study. High-resolution mass spectrometry analysis of the spent media revealed that, in addition to squalene accumulation by the yeast, arabitol, succinic acid, mannitol, benzoic acid, and citric acid were produced as extracellular products from crude glycerol.
This study presents a novel bioeconomy optimization framework, BiOpt, designed to address critical questions regarding the strategic use of limited US biomass resources for biofuel production. By integrating detailed techno-economic analyses, life cycle assessments, and resource assessment data, BiOpt optimizes resource distributions across competing technologies to maximize economic performance and/or minimize greenhouse gas emissions. Using feedstock scenarios from the 2023 Billion Ton Study, the analysis explores optimal biomass allocations across sustainable aviation fuel, diesel, and marine biofuel conversion pathways given varying production targets and policy incentives. Results demonstrate distinct feedstock preferences and pathway utilizations when prioritizing economic returns vs. emissions reductions. For instance, fats, oils, and greases were highly favored in cost-optimized scenarios, while low-carbon feedstocks such as wet waste dominated greenhouse gas-minimized strategies. The findings underscore the pivotal role of policy incentives and technological advances in shaping biofuel supply chains and provide actionable insights for scaling sustainable biofuel production to decarbonize hard-to-electrify sectors. This framework offers a robust tool for policymakers and stakeholders to evaluate biofuel strategies that balance energy output, economic viability, and environmental impact.
This study tests the hypothesis that raw fig waste can be utilized for thermophilic butanol production without pretreatment and that optimizing carbon-to-nitrogen (C/N) and carbon-to-phosphorus (C/P) ratios can enhance fermentation performance. The research is significant for addressing challenges such as food waste valorization, reducing fossil fuel dependency, and contributing to carbon-neutral goals. Economic feasibility is achieved by eliminating costly pretreatment steps and lowering raw material costs. In the mesophilic stage, mixed acidogenic sludge was used for selective butyrate production, followed by butanol synthesis in the thermophilic stage using Thermoanaerobacterium thermosaccharolyticum DSM 571. The effect of external nitrogen and phosphorus supplementation was evaluated using a Box-Wilson experimental design, with C/N (10-400) and C/P (50-2000) ratios as variables. The highest butanol concentration (0.78 g L-1) was obtained at C/N 250 and C/P 950, while the optimum C/N/P ratio was determined as 100/0.4/0.105, increasing butanol production by 30% compared with the control. These findings introduce a new approach in biobutanol production and highlight the industrial potential for integrating agricultural waste into sustainable energy systems.
Efficient and sustainable pretreatment is critical for improving fermentable sugar yields from lignocellulosic biomass. Biomass was subjected to two pretreatment approaches using choline chloride:glycerol (1:2), followed by dilute acid hydrolysis (1.99% H2SO4, 121 degrees C, 1 min). The effects of temperature or microwave power, treatment time, and liquid-to-solid ratio (LSR) were evaluated using response surface methodology to determine optimal conditions. Microwave pretreatment (460 W, 64.8 s, LSR 9.90 w/w) yielded 69.31 g L-1 fermentable sugar content (FSC), corresponding to 0.61 g fermentable carbohydrate per gram of untreated barley husks. The temperature-controlled reactor (TCR) achieved optimal conditions at 101.32 degrees C, 37.42 min, and LSR 4 w/w, yielding 47.93 g L-1 FSC and 0.40 g g-1 fermentable carbohydrate per g of untreated barley husks. The hydrolysates exhibited distinct sugar profiles. The TCR produced mainly xylose and fructose, with sucrose and maltose undetected. Microwave pretreatment produced higher glucose levels alongside xylose and fructose. Microwave pretreatment also reduced inhibitory compounds, including 5-hydroxymethylfurfural (HMF) and furfural. Both approaches suppressed benzoic acid formation through effective delignification and modified the chemical composition of barley husks by reducing extractives and lignin while improving cellulose availability. Microwave-assisted deep eutectic solvent pretreatment required a shorter processing time, produced a higher sugar yield, and reduced inhibitor formation. The results suggest that deep eutectic solvent (DES)-based microwave pretreatment is a promising and selective strategy for the valorization of barley husks as a lignocellulosic feedstock.
In the context of growing global demand for chemicals and renewable fuels, levulinic acid (LA) appears as a key platform chemical owing to its ability to be transformed into a wide range of industrial derivatives. This study investigates the chemical conversion of cellulose fraction of rice husk (RH) into LA, focusing on the influence of key reaction parameters and the kinetic behavior of the process within the framework of an integrated biorefinery system. The results of the experimental design indicate that temperature and solid loading are influential factors in the chemical conversion of cellulose fraction of RH to LA, finding an optimal reaction temperature of 167.27 degrees C and a solid load of 8% w/v. In parallel, it was found that a concentration of 5% v/v sulfuric acid maximizes the efficiency of the process, avoiding undesirable by-products. From a kinetic perspective, the reaction follows a pseudo-first-order model with a kinetic constant of k = 0.0309 min-1, a coefficient of adjustment R 2 = 0.9892 and an activation energy for the reaction of 46.2 kJ mol-1. These findings contribute to the understanding of the LA production process, thereby enhancing the understanding of the underlying reaction mechanisms for potential future applications.
