Biofuels Bioproducts & Biorefining-Biofpr最新文献

This study addresses significant process challenges associated with the reactive nature of hemicellulose-derived furan intermediates in aqueous mediums. A continuous agitated cell reactor was used to intensify the extractive reaction using methyl isobutyl ketone as an extractive phase to isolate in situ the furan products obtained by dehydration of hemicellulose sugars in aqueous media, using sulfuric acid as catalyst. The study, as part of a two-stage investigation, examined the influences of reaction temperature (110–140 °C), residence time (30–120 min), catalyst concentration (0.1–0.2 mol L⁻¹) and agitation frequency (2–9 Hz) in a single-phase medium using a definitive screening design of experiment. The aim of this initial experimentation stage was to identify the most statistically significant variables, which would serve as a benchmark for the subsequent evaluation of a biphasic medium. The highest glucose and xylose conversions obtained for single-phase aqueous operation were 30.6% and 61.4%, respectively, achieved for the highest temperature of 140 °C and 120 min residence time. At these conversions, the yield was 3.6% for 5-HMF, and 27.9% for furfural. The low yield was due to the degradation of the reactive intermediate furans in the aqueous phase. Acid concentration and the agitation frequency showed a significant effect on the conversion of the sugars. When using the biphasic extractive reaction system at 125 °C and 120 min residence time, the conversion of glucose and xylose rose to 45.9% and 78.5%, respectively, and the selectivity of 5-HMF (23.1%) and furfural (83.4%) and the yields (10.6% for 5-HMF and 65.5% for furfural) of furan in the biphasic system more than doubled in comparison with the use of single-phase operation. Two industrial hemicellulose hydrolysates were also investigated in a biphasic system, with one achieving maximum yields of 5-HMF and furfural at 21.7% and 37.9%, respectively, influenced by its higher oligomer content. The other stream exhibited furfural and 5-HMF yields of 45.5% and 17.5%, respectively, reflecting a simpler composition and a more favorable C5 sugar profile.

Fishing waste and byproducts, whether naturally occurring or from industrial processing, are important sources of high-value compounds. Fertilizers, biomaterials, cosmetics, biolubricants, and biodiesel are some of the substances that can be obtained from these residues. The objective of this study was to conduct a theoretical and experimental investigation of the biocatalytic production of ethyl esters through the enzymatic hydroesterification of residual tilapia (Oreochromis niloticus) oil. Eversa Transform 2.0 lipase was used during the esterification stage, with the Taguchi methodology applied to assess the effects of varying parameters: temperature (25, 40, and 55 °C), molar ratio of free fatty acids (FFA) to ethanol (1:1, 1:5, and 1:9), biocatalyst concentration (1%, 5%, and 9%), and reaction time (1, 3, and 5 h). Statistical analysis revealed that the amount of biocatalyst was the most significant factor, followed by temperature. The optimal levels identified were 5 h of reaction at 25 °C, with a 1:1 (FFA/ethanol) molar ratio and 9% biocatalyst, resulting in an experimental conversion of 89.94 ± 0.09%. A docking and molecular dynamics study was also conducted, evaluating the stability of Eversa Transform 2.0 lipase with FFAs, and the coupling of the enzyme’s catalytic site with the substrate was observed. Myristic and oleic acids bound near the enzyme’s active site, exhibiting favorable free energy and forming hydrogen bonds, alkyl interactions, and π-alkyl interactions, as revealed by an in silico study. This research aligns with key Sustainable Development Goals (SDGs), including SDG 7 (Affordable and Clean Energy) and SDG 9 (Industry, Innovation, and Infrastructure), and SDG 12 (Responsible Consumption and Production), by fostering the use of renewable energy and supporting more sustainable industrial processes.

The energy potential of sugarcane bagasse, a byproduct of one of the most abundant crops, has attracted significant attention as a renewable energy source. However, optimizing the pyrolysis process to maximize energy recovery and the quality of the products derived from this biomass remains challenging. This study investigated the influence of pellet density on the yields of biochar, bio-oil, and noncondensable gases (NCG) from the pyrolysis of sugarcane bagasse conducted at different temperatures. The pyrolysis tests were conducted at three different temperatures (400 °C, 600 °C, and 800 °C) using pellets with two distinct densities (D1 and D2). Four processes were carried out: pyrolysis at 400 °C with D1 pellets (T400D1); pyrolysis at 600 °C with D1 pellets (T600D1); pyrolysis at 600 °C with D2 pellets (T600D2); and pyrolysis at 800 °C with D2 pellets (T800D2). The results demonstrate that pyrolysis at higher temperatures (600 °C vs 400 °C and 800 °C vs 600 °C) led to a greater mass yield of NCG, whereas lower temperatures favored a higher mass yield of biochar, but bio-oil yields showed variability and were unpredictable. Similar trends were observed for the energy content. Higher density pellets (D2) enhanced biochar production whereas lower density pellets (D1) increased NCG yields. This study contributes to a better understanding of the pyrolysis process and highlights the need for optimized conditions to improve the sustainability and energy efficiency of biomass conversion technologies.

Black wattle (Acacia mearnsii De Wild.) is a key tree crop in South Africa, valued for its bark and timber, both of which contribute significantly to export revenue. Wattle bark harvesting begins with the rainy season in September and extends to May. During this time, harvested bark is transported to three processing facilities. The journey, which includes stripping and transit and lasts for several days, exposes the bark to varying environmental conditions, such as temperature, rainfall, humidity, and light, all of which can influence the quality of the bark. The decrease in extractives, darkening of the bark, and loss of tannins are all examples of bark quality degradation. To replicate postharvest conditions, experiments were conducted using fresh bark samples collected bimonthly from September 2020 to July 2021. These samples were subjected to varying temperature, light, and moisture conditions to simulate real-life scenarios and quantify the extent of bark quality degradation. Quality parameters, including total extractives, tannin content, and Lovibond color were analyzed. Advanced statistical techniques, such as principal component analysis (PCA) and redundancy analysis (RDA), were used to identify patterns and relationships among variables. The findings revealed that seasonal changes and site-specific conditions influenced bark quality significantly, particularly affecting Lovibond color, a key quality indicator. This study underscores the impact of pre-extraction environmental conditions on the quality of bark extractives. It is essential to develop strategies to mitigate these effects in order to minimize variability and ensure consistent production of high-quality products. The study also highlights the need for more in-depth work in the future.

Variability in fossil fuel prices and a commitment to reducing greenhouse gas (GHG) emissions have driven the US pulp and paper (P&P) industry to adopt technologies that decrease reliance on fossil fuels. In this regard, enhancing energy efficiency is crucial to the decarbonization of the sector. This study evaluates several energy-efficient alternatives for one of the main P&P products, linerboard, focusing on black liquor concentration, steam generation, and paper-drying processes. The key technologies assessed include: (a) high-efficiency recovery boilers and electric boilers as substitutes for natural gas, (b) graphene oxide (GO) nanofiltration membranes and mechanical vapor recompression (MVR) for black liquor concentration, and (c) advanced paper machine techniques like shoe presses, nylon mesh felts, and condebelt drying. Using process simulations in Windows-based Generic Energy and Material System (WINGEMS), Life Cycle Assessment in OpenLCA, and financial modeling, the study found that GO membranes for black liquor and condebelt drying were the most effective, reducing emissions by 15%. High-efficiency recovery boilers added another 10% reduction. Cost analysis showed that technologies like nylon felts, shoe presses, and MVR not only cut operational costs but achieved carbon reductions of up to 8%, with costs of avoided carbon (CAC) ranging from −$67 and −$19 per metric tonne of CO₂-eq. avoided. In contrast, GO membranes and recovery boilers had higher CAC values, from $237 to $392 per metric tonne. The findings suggest that the benefits of MVR, GO membranes, electric boilers, and condebelt drying increase with greater renewable energy use in the US grid, highlighting the decarbonization potential of electrifying the pulp and paper sector.

This study investigated the biosynthesis of ethyl oleate (EO), the main constituent of biodiesel, via the esterification of oleic acid with ethanol, catalyzed by Candida antarctica lipase B (CALB) immobilized on a low-cost support derived from cashew apple bagasse (CAB) lignin. Cashew apple bagasse lignin extraction was carried out through an acid-alkali process and used to produce the CAB-lignin conjugated with magnetite (Lig-MNP) composite, which served as the support for enzyme immobilization. The biocatalyst (Lig-MNP/CALB), obtained through the immobilization process, exhibited an activity of 13 U g⁻¹ and was subsequently applied in esterification reactions to evaluate its catalytic efficiency in comparison to the free enzyme. Acid-to-alcohol molar ratio, temperature, and catalytic load were evaluated. Under optimal conditions – 40 mg mL⁻¹ catalyst load, 40 °C, and a 1:2 molar ratio – Lig-MNP/CALB achieved a maximum EO conversion of 90%. The immobilized enzyme demonstrated operational stability over multiple cycles and was easily recovered through magnetic separation. The purified biofuel reached approximately 90% purity in ethyl oleate and 98% in total esters content. These results highlight the potential of the biocatalyst for sustainable biofuel production.

Seaweeds are potential feedstocks for biorefinery approaches, owing to their carbohydrate content, high biomass production and lack of lignin content, which makes saccharification more feasible. The seaweed sugar-rich hydrolysates can be used to produce alternative protein sources, such as mycoprotein, to meet the increasing global protein needs in a sustainable way. Therefore, this study aimed to produce biomass of the filamentous fungus Aspergillus ibericus MUM 03.49, a non-mycotoxin producer, from a seaweed hydrolysate. Firstly, hydrothermal pretreatment of Codium tomentosum was performed in an autoclave, followed by enzymatic hydrolysis using the commercial enzyme cocktail Cellic® Ctec 2 or a fungal enzyme crude extract. With the commercial enzyme cocktail, the maximum saccharification of cellulose and xylan was obtained when using 500 U g⁻¹ (around 75% and 30%, respectively), while when using the fungal enzyme extract, around 100% cellulose and 50% xylan conversion were achieved with 180 U xylanase g⁻¹. The obtained sugar-rich hydrolysate was used as the culture medium for A. ibericus growth in a stirred tank bioreactor. Several values of volumetric oxygen mass transfer coefficients (k_La) were used, from 20 to 66 h⁻¹, and a maximum biomass yield of 85% was achieved in batch cultures. The fungal biomass recovered contains 28% (w/w, dry mass) protein, 28% ash and 3% lipids. Aspergillus ibericus biomass has great potential as a protein alternative source for several applications, including in the food and feed industries.

The growing demand for sustainable bioproducts in industrial applications highlights the need to utilize agricultural biomass for sustainability. This study developed green biocomposites by incorporating lignin particles (LPs), extracted from the black liquor of palm shell waste, into a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) matrix reinforced with nonwoven kenaf bast fiber mats. The reinforced biocompatible PHBV polymer was further strengthened by adding LPs at concentrations of 0, 1, 3, 5, and 7 wt%. The biocomposites were fabricated using hot compression molding and were evaluated systematically for water-barrier, mechanical, morphological, functional, and thermal properties. A single-factor analysis of variance (ANOVA) was used for statistical analysis. The results demonstrated a 28% increase in tensile strength and a 15% increase in flexural strength at 5 wt% LP loading. Water absorption was reduced by 23% at the highest filler concentration, indicating enhanced water-barrier properties. Improved interfacial bonding between LPs and the PHBV/kenaf fiber matrix was confirmed through morphological analysis, and Fourier transform infrared (FTIR) spectroscopy revealed the presence of strong interactions between the components. However, thermal stability decreased slightly with LP incorporation, and mechanical performance declined at 7 wt% due to particle agglomeration. Overall, optimal performance was achieved at 5 wt% LP loading, highlighting the potential of PHBV/kenaf/LP biocomposites as sustainable materials for environmentally friendly applications, particularly in packaging, addressing critical environmental and human health concerns.

Biobased products can achieve carbon negativity by storing biogenic carbon in the technosphere through circular loops. Quantifying these benefits requires quantitative assessment tools such as life cycle assessment (LCA). However, the LCA of biobased materials is not straightforward due to the complexity of addressing agroecosystem carbon dynamics and the timing of emissions. The aim of this research is to apply the novel framework of biobased materials and products-life cycle assessment (BBM-LCA) to the example of polylactic acid (PLA) to show how it can address biogenic carbon and timing issues of emissions by combining net ecosystem exchange (NEE) and dynamic LCA. BBM-LCA adapts two aspects of conventional LCA to estimate the climate impact of biobased products more accurately. First, concerning the absorption of atmospheric carbon during cultivation, BBM-LCA uses NEE to account for all biogenic emissions occurring within the agricultural ecosystem. This means that it is not limited to the absorption of carbon by agricultural crops. Second, concerning the calculation of climate impacts, BBM-LCA adopts dynamic LCA as a time-dependent approach, to generate a time-sensitive global warming potential (GWP). The example of PLA proves that BBM-LCA is an effective instrument for calculating the climate impact of biobased products due to the implementation of a holistic lifecycle approach and a dynamic impact calculation method. BBM-LCA accounts for the carbon sequestration benefits of recycling, recognizing its actual impact over time in multiple lifecycles. This feature makes BBM-LCA preferable over conventional LCA, which struggles to track greenhouse gas (GHG) emissions at different points over multiple years across the multiple lifecycles of recycled products.

Lignocellulosic biomass is an important source of renewable chemicals and materials but its full valorization is necessary in order to achieve economic and sustainability goals. This study proposes a two-step approach for the valorization of lignocellulosic biomass combining solvent-assisted fractionation and catalytic oxidation with molecular oxygen to generate cellulose and formic acid. An industrially relevant lignocellulosic substrate, beech wood, was fractionated under a nitrogen atmosphere using either an organosolv (methanol or ethanol) or ionosolv (ionic liquid) aqueous solvent to produce dissolved hemicellulose and lignin as well as a cellulose-rich solid. The dissolved components were oxidized catalytically to formic acid and its derivatives in a second step using the fivefold vanadium substituted Keggin-type polyoxometalate H₈[PV₅Mo₇O₄₀]. Enzymatic hydrolysis of the cellulose-enriched solid generated purified glucose higher in yields than the single-step comparison method. The organosolv-fractionation increased enzymatic saccharification to 78% whereas the ionosolv-fractionation increased the saccharification yield to 68%, in comparison with 18% for the one-step conversion and only 8% for the untreated beech wood. In the oxidation step, a 28% formic acid yield was achieved under 125 °C, 1200 rpm, 30 bar oxygen, and 6.5 h reaction conditions. The improvements observed for the two-step approach are attributed to the influence of the solvent on the catalyst preventing the latter from interacting with the cellulose-enriched solid, which improved the quality of the pulp and increased the overall formic acid yield.