Biofuels Bioproducts & Biorefining-Biofpr最新文献

Efficient hydrolysis of hemicellulose to fermentable carbohydrates is crucial for producing butanol from lignocellulose. This study investigates hydrothermal pretreatment catalyzed by dilute trifluoroacetic acid (DTFA) to enhance the hydrolysis of hemicellulose in corncob. DTFA pretreatment generated a fermentable hemicellulose hydrolysate containing 75–80% xylan as xylose and a glucan-rich solid. Pretreatment at 150 °C with 0.05 M trifluoroacetic acid released 80% xylan, yielding 23 g L⁻¹ xylose and 13.8 g L⁻¹ other sugars. Enzymatic hydrolysis of the 65.5% glucan solid yielded a cellulosic hydrolysate with 26 g L⁻¹ glucose. DTFA pretreatment improved hydrolysis efficiency by 243% over untreated corncob and 62% over dilute sulfuric acid pretreatment. Acetone–butanol–ethanol (ABE) fermentation of the hydrolysates by Clostridium acetobutylicum produced 7.8–7.9 g L⁻¹ ABE, utilizing 97% glucan and 75% xylan. The process was assessed based on the concentration of inhibitors and fermentable sugars. Dilute trifluoroacetic acid pretreatment yields 187 g of ABE per kg of corncob, compared with 42 g for DSA.

Microalgae oil (MAO), a third-generation biofuel, can support global transportation fuel demand as a fossil fuel substitute. Schizochytrium sp. MAO is particularly promising for direct use in compression ignition (CI) engines, especially in the marine sector, due to its adaptability and high oil yield. This study investigated the performance, emissions, and optimization of a single-cylinder marine diesel engine operating on MAO and MAO/diesel oil (DO) blends. The results show that MAO significantly reduced nitrogen oxide (NOx) and carbon monoxide (CO) emissions by up to 59%, despite its higher viscosity and density and its lower heating value compared with DO. Brake-specific fuel consumption (BSFC) increased by 46%, but brake power and brake thermal efficiency (BTE) decreased by up to 40% and 26%, respectively. After 30 h of operation, the lubricant oil (LO) in MAO-fueled engines contained 15% less Zn, 19% less P, and 16% less Ca than that in DO-fueled engines.

The bark of forest species is a resource with a high concentration of bioactive compounds that have antioxidant, chelating and antimicrobial properties. Bioprospecting bioactive compounds from bark can generate income for local communities and contribute to the social and economic development of rural areas, especially in regions where traditional logging activity is in decline. Optimizing extraction is crucial to ensure that extracts with a high content of bioactive compounds are obtained. In this study, we optimized the extraction of bioactive compounds from the bark of Stryphnodendron adstringens and Myrcia eximia, evaluating the effects of mixtures of water, ethanol, and acetone on the chelation of Fe(II), Zn(II), and Cu(II) ions and on the inhibition of the urease enzyme. The results showed that both extracts have chelation and urease inhibition capacity. The simplex–centroid experimental design identified the ideal formulations for each response. Notably, maximum urease inhibition was achieved with a mixture of 7% water, 50% ethanol, and 43% acetone for S. adstringens and a mixture of 8% water, 75% ethanol, and 17% acetone for M. eximia. These findings highlight the importance of optimizing extraction conditions for each species, as efficiency is sensitive to solvent polarity and material matrix.

This study explored the valorization of two carbohydrate rich food wastes, a sugary (spoiled dates, SD) and a starchy (wasted rice, WR) one, for the biotechnological production of α-amylase, biohydrogen (bioH₂), and methane (CH₄). Initially, the bioH₂ and CH₄ production potentials of raw SD and WR were assessed without any pretreatment, via dark fermentation and anaerobic digestion, respectively, to evaluate the need of sacharification of the wastes for achieving efficient yields. For the production of amylolytic enzymes the bacterium Bacillus amyloliquefaciens was used. Aerobic experiments with synthetic media were initially performed to evaluate the effect of carbon and nitrogen sources on microbial growth, substrate uptake and stimulation of α-amylase production. Subsequently a mixture of the SD and WR, supplemented with peptone, was used as a substrate for α-amylase production, achieving a maximum enzymatic activity of 35.7 ± 1.1 AU mL⁻¹. The impact of enzymatic and acid saccharification on biofuel production was then evaluated using commercial α-amylases, crude α-amylase produced in situ by B. amyloliquefaciens, and HCl. Commercial enzymes maximized bioH₂ yields, while crude α-amylase also enhanced production considerably. HCl pretreatment improved WR conversion but reduced bioH₂ yields from SD. Saccharification showed only a limited effect on CH₄ production, with no statistically significant improvements over untreated WR. Overall, SD and WR show strong potential as zero-cost feedstocks for α-amylase and gaseous biofuel production, supporting circular economy principles. Valorization of these carbohydrate-rich wastes could reduce feedstock costs and provide a sustainable approach to enzyme and bioenergy generation.

The industrial implementation of many lab-scale biorefinery designs has been significantly hampered by the lack of availability of efficient and cost-effective chemical recovery techniques. This is of particular importance for organic solvent-based biorefineries such as those that use or produce aqueous butanol–water streams which, based on phase equilibrium, may contain up to 7 wt% butanol. Vapor stripping–vapor permeation (VSVP), a variation of pervaporation with a vapor phase feed, has emerged as a promising approach for butanol recovery from dilute aqueous solutions. It combines the butanol-enriching properties of vapor stripping with a vacuum-driven organophilic membrane separation. The impact of feed temperature, feed vapor flow rate, and temperature offset between the feed and membrane were investigated to evaluate their effects on VSVP performance and determine optimal operating conditions. Fluxes were found to increase with both feed temperature and feed vapor flow rate, while permeate butanol concentration was found to remain largely constant at an average of 72 wt% butanol. The best operating conditions for butanol recovery were found to be a feed temperature of 80 °C, a membrane temperature of 70 °C, and a feed vapor flow rate of 3.0 L min⁻¹. Under these conditions, the minimum membrane area required to reduce the butanol concentration from 7 to 1 wt% in a model aqueous phase generated from processing 1 metric tonne of biomass per hour was calculated to be 87 m². This work demonstrates great potential for the use of VSVP to perform butanol recovery from aqueous solutions.

The use of biojet and sustainable aviation fuels (SAF) as low carbon-intensity (CI) fuels is likely to be the primary pathway to decarbonize aviation. ‘Waste lipids’, such as fats, oils, and greases (FOGs), are preferred feedstocks due to their lower CI. However, they are mainly used to make biodiesel or renewable diesel. Therefore, there has been a significant increase in the price paid for “waste lipids” and consequently an increase in their collection. However, due to the limited availability and competition, waste-lipid/FOG feedstocks are unlikely to meet 2030 demands for biojet or SAF. Consequently, increasing amounts of SAF are produced from higher CI plant-derived lipids such as soya and rape/canola. Currently, about 20% of the world’s vegetable-derived lipids are used to make biodiesel or renewable diesel and SAF, with the majority allocated to food and oleochemicals. The rising value and scarcity of waste-lipid/FOG feedstocks, coupled with competition from both traditional markets (e.g., edible oil, cosmetics) and biofuels has heightened interest in lipid feedstocks. Greater attention will be directed towards the CI of lipids, if the overall objective is to decarbonize the fuel. However, biodiesel/renewable diesel benefits from lower costs, increased yields, and lower CI than biojet/SAF. This will result in increasing competition for lipid feedstocks between the biodiesel, renewable diesel, and biojet/SAF markets.

The review examines the benefits of skeletal based (endoskeleton an exoskeleton) catalysts toward improving the circular economy. These biomass materials provide a unique benefit owing to their availability, low cost, and eco-friendliness. The features of these catalysts were discussed through the lens of some characterization techniques, like Brunauer–Emmett–Teller, X-ray diffraction, and thermogravimetric analysis–derivative thermogravimetry. The chemical, thermal, and morphological properties were critically analyzed. These analyses provide insights into the potential of skeletal based catalysts in catalyzing transesterification and interesterification reactions. Furthermore, this review explores kinetics, thermodynamics parameters, and further studies associated with these materials were examined.

The cultivation of microalgae to produce biofuels and other value-added products constitutes a compelling biotechnological and sustainable alternative. This study assessed the production of pigments, proteins, carbohydrates, lipids, and fatty acid methyl esters by Scenedesmus obliquus cultivated in various alternative media (AM) derived from four types of manure digestate: swine (SD), cattle (CD), a combination of swine and cattle, and different stable manures (FD), in addition to vermicompost tea and vermicompost leachate, comparing these findings with the standard Bold’s Basal Medium (BBM). All the AM enhanced the production of carbohydrates and lipids relative to BBM, except for FD, which did not exhibit a substantial increase in carbohydrates. The CD and FD media enhanced protein production by 28.37% and 24.9%, respectively, in comparison with BBM. In the AM, 12 fatty acids were found, whereas only three were recognized in the BBM. The biodiesel produced from AM satisfied all of the specified quality metrics, except for the SD medium, which exhibited a superior cetane number but failed to fulfill all criteria; conversely, the biodiesel sourced from BBM met four of the standards. The results indicate that manure digestates are appropriate substrates for the cultivation of S. obliquus, as they promote the synthesis of value-added chemicals and facilitate the generation of high-quality biodiesel. The utilization of unconventional methods represents an approach that reduces environmental impact and may lower production costs, hence improving process sustainability.

When selecting economically and environmentally advantageous genotypes for domestication in a biofuel supply chain, variability of cell-wall composition within a feedstock population and its impact on biorefinery metrics must be understood. We performed a life cycle assessment (LCA) on a poplar-to-ethanol supply chain to quantify global warming potential and cumulative energy demand as affected by variable carbohydrate content in a large representative natural variant population of Populus trichocarpa. The results showed that both environmental metrics decrease with increasing tree size and with increasing biomass carbohydrate content. These trends parallel prior economic results and provide clear direction to breeders or genetic engineers when improving poplar cultivars.

Olive stones (OS), a common form of agroindustrial waste, are rich in lignin and are typically burned for energy rather than being converted into value-added products. This study investigates the efficient extraction of lignin from OS using deep eutectic solvents (DESs) under microwave-assisted conditions. The DES mixtures employed included choline chloride (ChCl) combined with acetic acid (AA), formic acid (FA), or lactic acid (LA). The purity, Fourier transform infrared (FTIR) spectra, elemental composition, particle size, and color of DES-extracted lignin (DES-L) obtained from OS treated at 150 °C for 1 h were determined. In addition, FTIR, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analyses were performed on the solid residue after DES treatment. Choline chloride/LA treatment achieved the highest delignification ratio (80.01%). Choline chloride/LA-lignin exhibited a smaller particle size (238.4 nm) than ChCl/AA-lignin and ChCl/FA-lignin. Moreover, ChCl/LA-treated OS showed a higher surface area (3.113 m² g⁻¹) and total pore volume (7.215 × 10⁻³ cm³ g⁻¹). In contrast, ChCl/AA treatment produced lighter colored lignin (L* value: 44.29) than ChCl/FA or ChCl/LA treatments. All lignin samples exhibited purities greater than 87%. These results indicate that microwave-assisted DES pretreatment, particularly with ChCl/LA, is an effective and sustainable strategy for valorizing OS.