Search Results (422)

A sequential two-stage chemo-biocatalytic process was investigated for the conversion of D-xylose to furfuryl alcohol (FOL), an important furan derivative widely used in the manufacture of resins, polymers, fuels, and other value-added products. In the first stage, D-xylose was dehydrated to furfural (FAL) in a ternary Betaine:Formic acid:Malonic acid–water (Bet:FA:MA–H₂O) reaction medium. Under the selected conditions, a FAL yield of 65.8% was obtained from 22.5 g/L D-xylose using 15 wt% Bet:FA:MA at 170 °C for 30 min. For the subsequent bioreduction stage, a recombinant Escherichia coli strain co-expressing the aldehyde reductase EutG and glucose dehydrogenase (GDH) was constructed. Using glucose as a co-substrate, EutG–GDH whole cells were able to reduce commercial FAL at concentrations up to 150 mM under the selected conditions of 40 °C and pH 7.5. For the sequential process using the D-xylose-derived dehydration liquor, the acidic reaction mixture was adjusted to pH 7.5 and diluted from 98.7 to 30.0 mM FAL before whole-cell bioreduction. The conditioned 30.0 mM FAL feed was essentially completely converted to FOL within 24 h. These results demonstrate the laboratory-scale feasibility of sequentially combining Bet:FA:MA–H₂O-mediated D-xylose dehydration with EutG–GDH whole-cell FAL reduction after interstage pH adjustment and dilution. Full article

Native Lactic Acid Bacteria (LAB) isolated from fruits and vegetables in Chile’s Maule Region were identified as Lactiplantibacillus plantarum and L. pentosus. Their growth and lactic acid production were evaluated under furan inhibitor stress (furfural and 5-methylfurfural (5-MF)) relevant to agroindustrial waste valorization. In fruit hydrolysates containing natural furans (11–57 mg/L), LAB grew similarly to inhibitor-free controls and produced 17–25 g/L lactic acid. Under controlled conditions, furfural at 12 g/L reduced bacterial growth by over 80% and decreased lactic acid production to only 2 g/L. In contrast, 5-MF at the same concentration allowed substantially higher tolerance, with up to 7 g/L lactic acid. Benchmarked directly against the commercial reference strain Lactiplantibacillus plantarum PL8014 under identical conditions, the native isolate B1 matched or exceeded PL8014’s lactic acid output in most furfural and 5-MF concentrations tested, including the two most severe 5-MF conditions. Logistic growth and Luedeking–Piret models accurately described both bacterial growth dynamics and lactic acid production kinetics under all inhibitory conditions (R² > 0.96). Inhibitor concentration proved more critical than inhibitor type, although furfural consistently showed stronger potency. These findings confirm the biotechnological potential of native Maule LAB and provide quantitative kinetic parameters for optimizing lactic acid production from lignocellulosic waste, supporting circular economy strategies. Full article

Black highland barley, rich in phenolic compounds and β-glucans, is increasingly used in craft beer brewing, but the dynamic metabolic changes across its processing chain remain unclear. This study integrated GC×GC-TOF MS based flavoromics with UHPLC-QTRAP-MS based widely targeted metabolomics to track volatile and non-volatile metabolites from raw grain (K1) through germinated malt (K2) and roasted malt (K3) to finished beer (K4). A total of 256 volatile compounds and 615 non-volatile metabolites were identified. Alcohols and hydrocarbons dominated K1. Germination (K2) enriched aldehydes and reduced esters by 66%. Roasting (K3) generated Maillard reaction products, including 2,3,5-trimethylpyrazine (198.4-fold increase) and furfural (20.2-fold increase). Fermentation (K4) shifted the profile to ester dominance (40.95%), with isoamyl alcohol (ROAV = 71.59) and 2-undecanone (ROAV = 65.37) as the principal aroma contributors. Notably, 94.1% of phenolic and flavonoid compounds (168 of 184) exhibited higher abundance in finished beer than in raw grain. Their levels declined after roasting and then accumulated during fermentation. Cross-omics correlation indicated a strong association between furfural and its pentose phosphate precursor (ρ = 1.00, p < 0.001). These findings demonstrate that fermentation acts as the decisive metabolic turning point that simultaneously shapes the flavor profile and nutritional quality of black highland barley beer. The finished beer contained 250.45 mg GAE/L total phenolics and 97.91 mg RE/L total flavonoids, with ABTS and DPPH radical scavenging rates of 87.41% and 92.68%, respectively. Full article

Abelmoschus manihot (L.) flowers are widely used in traditional Chinese medicine, whereas the roots are often discarded as agricultural waste. The compact cellular and tissue architecture of the roots hinders the release of intracellular metabolites, thus impeding their reutilization. Here, enzyme-assisted ultrasonic extraction was developed to obtain a polysaccharide-rich crude extract from A. manihot roots. Orthogonal optimization identified pH 4.5, a temperature of 60 °C and a cellulase dosage of 6% (w/w) as the optimal extraction conditions, giving an extraction yield of 21.59%. The phenol–sulfuric acid assay indicated a total carbohydrate content of 75.09% (glucose equivalents). Structural analysis by Fourier transform infrared (FT−IR) confirmed the presence of characteristic polysaccharide functional groups, while monosaccharide composition analysis via high-performance liquid chromatography (HPLC) revealed the major components of glucose, glucuronic acid, rhamnose, galacturonic acid, etc. Inspired by the traditional use of A. manihot extract in papermaking, its preliminary hair care-related properties were further evaluated. At a concentration of 30 mg/mL, the extract solution inhibited Malassezia furfur growth by 84%, reduced wet and dry combing work by 16.93% and 30.86%, and increased tensile strength and tensile fracture energy by 13.04% and 14.84%, respectively. Scanning electron microscope (SEM) images suggested smoother hair fiber surfaces after treatment. These results highlight the extract’s great potential for hair care cosmetic products. Full article

This study evaluated carob (Ceratonia siliqua L.) flour as a functional ingredient for improving the nutritional and sensory properties of wheat-based biscuits. Mature carob pods collected from eastern Algeria were processed into fine flour and characterized for physicochemical properties, antioxidant activity, and volatile and phenolic profiles. GC–MS analysis revealed a complex volatile profile dominated by organic acids, aldehydes such as furfural and benzaldehyde, and Maillard-derived compounds, including 2-acetylpyrrole and furfuryl alcohol, associated with caramel and cocoa-like aromas. LC-MS profiling identified several flavonoids and phenolic acid derivatives, including quercetin-, myricetin-, and kaempferol-glycosides, as well as gallic acid glucoside, confirming the high antioxidant potential of carob flour. Biscuits were formulated by substituting wheat flour with 30% and 60% carob flour. Sensory evaluation revealed significant increases in color intensity, caramel odor, sweetness, and chocolate-like flavor (p ≤ 0.05), with the 30% substitution achieving the highest overall acceptability. These sensory attributes were associated with the volatile and phenolic profiles, particularly the presence of Maillard-derived furans and flavonoid compounds. These findings demonstrate that carob flour can enhance the sensory characteristics and contribute to the functional potential of biscuits, supporting its use as a natural cocoa substitute and source of bioactive compounds in bakery products. Full article

This study evaluated the anaerobic valorization of real, non-detoxified sugarcane bagasse-derived pentose liquor. Direct fermentation without nutrients, co-substrate, or buffering was limited, reaching low-to-moderate (37–54%) carbohydrate conversion efficiency at low organic loading rate (OLR < 5.6 kg COD m⁻³ d⁻¹) levels. Hydrogen yield (HY) was also low (0.63–0.89 mol H₂ mol⁻¹ carbohydrate_converted) under these conditions. Increasing pentose liquor concentration up to 0.8 L L⁻¹ and OLR of 30.2 kg COD m⁻³ d⁻¹ suppressed hydrogen production, coinciding with lactate accumulation and the occurrence of homoacetogenesis. Enhanced fermentation with sucrose, nutrients, buffering, shorter hydraulic retention time (12 h) and 37 °C improved stability and carbohydrate conversion (50–61%) under higher OLR, although HY considerably decreased (0.14–0.35 mol H₂ mol⁻¹). Methanogenesis was effective in both single- and two-stage systems, with carbohydrate conversion usually above 95%, COD removal up to 83.5%, methane fractions above 60%, and methane yields reaching 299.8–301 NmL CH₄ g⁻¹ COD_removed. Furfural and 5-HMF showed phase-dependent transformation, indicating partial in situ detoxification during anaerobic conversion. Overall, pentose liquor is better valorized through integrated hydrogen–methane recovery than by fermentation alone. Future studies should focus on both applying more effective strategies to buffer the fermentative stage and adopting more conservative approaches (lower OLR) to start up the methanogenic systems. Full article

Biomass-derived fast pyrolysis oil (PO) represents a promising alternative fuel for aviation and heavy transport. However, its high content of oxygenated organic molecules necessitates catalytic hydrodeoxygenation (HDO) before it is viable to be sent to a refinery. Single-step upgrading processes have encountered significant challenges, particularly reactor plugging and catalyst deactivation. To address these issues, an initial stabilization step at lower temperatures has been proposed to stabilize the most reactive compounds in the oil prior to hydrodeoxygenation. In this study, a range of different carbon- and Al₂O₃-supported catalysts (Ni/Al₂O₃, sulfided NiMo/Al₂O₃, Ru/C, Pd/C, Pd/Al₂O₃, Pt/C, and Pt/Al₂O₃) were evaluated for furfural stabilization in a batch reactor for 1 h with an initial pressure of 90 bar H₂ and 180 °C with and without sulfur present. Sulfur tolerance was assessed by repeating all experiments with the addition of 1170 wt-ppm sulfur to the feedstock. The most active catalysts—Ni/Al₂O₃, Ru/C, Pd/C, and Pd/Al₂O₃—also exhibited the highest susceptibility to sulfur poisoning. Although Pt/C did not demonstrate the highest overall activity, sulfur addition appeared to enhance its performance, both in terms of furfural conversion and liquid yield of desired products. Full article

Various Maillard reaction products (MRPs) are formed in infant formula during thermal processing and storage. However, safety assessments are often based on individual compounds, which may not adequately reflect the potential risks associated with exposure to multiple coexisting components in real food products. Therefore, this study used GC–MS to screen for typical MRPs in infant formula. Based on the detection results, glyoxal, 2-acetylfuran, 2-furfural, and 5-hydroxymethylfurfural (5-HMF) were selected to establish a mixed-exposure system. Subsequently, using zebrafish as a model, we systematically evaluated the toxic effects of two mixture concentrations, 1/9 maximum non-lethal concentration (MNLC) and 1/3 MNLC, on the immune system, nervous system, gastrointestinal tract, and liver. The results showed that these four MRPs coexisted in infant formula and that combined exposure induced significant biological damage even at low doses. Both mixture concentrations significantly reduced neutrophil and macrophage levels and promoted apoptosis in central nervous system cells. The higher-concentration mixture further reduced T-cell counts, suppressed motor neuron development, and decreased locomotor activity during the light phase. In addition, the higher-concentration mixture decreased the gastrointestinal area, increased the liver area, delayed yolk sac absorption, and caused marked histopathological damage. Compared with single-compound exposure, combined exposure exerted more pronounced effects on immune- and neuro-related endpoints, suggesting synergistic interactions among different MRPs and identifying the immune and nervous systems as the more sensitive targets of toxicity. In summary, mixed exposure to typical MRPs in infant formula may pose a greater biological risk than that predicted by evaluations based on individual components alone. This study provides experimental evidence for identifying combined toxicity and improving the safety risk assessment of MRPs in thermally processed infant foods. Full article

The American cranberry (Vaccinium macrocarpon Aiton) is widely appreciated for its high nutritional value and characteristic volatile profile, making it an important raw material for the food industry, particularly in the sector of minimally processed products. However, thermal processing may significantly alter its volatile composition, leading to aroma losses and degradation of product quality. Therefore, understanding the impact of processing conditions on aroma stability is essential for developing new post-harvest technologies that preserve the volatile profiles of processed fruit products. The aim of this study was to evaluate the effect of thermal treatment and protein matrix modification on the volatile organic compound (VOC) profile of fresh-cut cranberry fruit. Samples were heated at 50, 100, and 200 °C, with and without gelatin addition as a protein-based matrix modifier. VOCs were analysed using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME–GC–MS). High-temperature treatment (200 °C) resulted in substantial changes in the volatile composition of the reference cranberry fruit and contributed to the complete loss of characteristic native terpenoids. The addition of gelatin significantly improved the retention of hydrophobic volatiles under thermal stress, maintaining D-limonene at 20.3% of the total volatile fraction, whereas this compound was absent in samples processed without the modifier. Furthermore, gelatin successfully altered the course of thermally induced reactions, reducing undesirable furfural formation from 23.95% to 7.28%. These changes indicate that protein-assisted matrix modification can effectively limit aroma degradation and preserve the volatile profile during thermal processing. The findings demonstrate the potential of this approach as a novel technological strategy for enhancing aroma stability, reducing processing-related quality losses, and supporting the development of fresh-cut cranberry products with enhanced volatile compound retention. Full article

With the increasing generation of textile waste, efficient chemical recycling methods are urgently needed. This study evaluates a hydrochloric acid-based process for recycling polycotton textiles (polyester/cotton blends), in which cotton is selectively hydrolyzed and converted into 5-(chloromethyl)furfural (CMF), while polyester is recovered. The impact of common non-polycotton fiber contaminants on process performance and product quality was systematically assessed. Cellulose-based fibers did not hinder the process and are suitable for CMF production, while most synthetic fibers were effectively removed without affecting the CMF yield. In contrast, animal fibers reduced the CMF yield and complicated acid recovery, indicating they should be avoided in the feedstocks. Additionally, polyacrylonitrile and wool persisted in the solid fraction, contaminating the recovered polyester and lowering its value. To improve process robustness and product quality, intermediate filtration and extended hydrolysis time are recommended. These findings highlight critical feedstock requirements and operational adjustments for scalable polycotton recycling. Full article

The economic viability of second-generation (2G) bioethanol production depends on the availability of robust, multistress-tolerant yeast strains capable of withstanding harsh industrial conditions. This study investigates animal manure as a novel ecological niche for discovering such strains, as microbes in these environments naturally adapt to high organic loading and fluctuating temperatures. From eighty-six initial isolates, twenty-nine demonstrated superior xylose fermentation at 37 °C. Eight high-performing isolates (C2-1, B1-2, B1-6, B2-6, B2-8, G1-4, G1-5, and G2-4) exhibited exceptional tolerance to ethanol, high temperatures, and lignocellulosic-derived inhibitors (acetic acid, formic acid, furfural, and vanillic acid). Molecular identification classified isolate C2-1 as Pichia kudriavzevii and the remaining seven as Candida tropicalis. In synthetic media, C. tropicalis B2-8 produced up to 16.33 g/L of ethanol using xylose (60 g/L) as the sole carbon source. While the undetoxified, highly acidic sugarcane bagasse hydrolysate completely inhibited yeast growth, the industrial potential of these strains was successfully validated using the concentrated, undetoxified enzymatic hydrolysate derived from the acid-pretreated sugarcane bagasse solids, which contained 30.15 g/L glucose and 25.58 g/L xylose. P. kudriavzevii C2-1 achieved ethanol titers of 6.02 g/L and 5.71 g/L at 37 °C and 40 °C, respectively. The C. tropicalis strains outperformed P. kudriavzevii, yielding 6.12–6.35 g/L at 37 °C and maintaining 5.75–6.19 g/L at 40 °C. These findings underscore the potential of manure-derived yeasts as resilient biocatalysts. Although their fermentation yields remain relatively low and require further metabolic optimization, their ability to survive and ferment in this concentrated, undetoxified enzymatic hydrolysate at elevated temperatures makes them promising candidates for further development in high-temperature ethanol fermentation (HTEF), offering a potential pathway toward reducing cooling costs associated with 2G biorefineries. Full article

The growing global demand for sustainable biotechnological routes for bioenergy production has paved the way for Brazil to position itself as a strategic leader due to its vast agricultural production and, consequently, agricultural residues, among which rice husk stands out. Although rice husk is widely used for energy cogeneration, its potential for producing high-value platform chemicals remains underexplored. This study aims to evaluate the production of value-added pyrolytic derivatives from rice husk by investigating the synergy between acid pretreatments and fast pyrolysis temperatures (350–600 °C). Thus, the experimental strategy involved intensifying the production of target compounds in the condensable fraction (bio-oil) from pyrolysis gases using different biomass pretreatments before fast pyrolysis according to the following conditions: (i) acid washing using acetic acid (10%), (ii) acid washing using nitric acid (0.1%) followed by impregnation using sulfuric acid (0.1–0.3%), and (iii) impregnation using sulfuric acid alone (0.1–0.3%). Fast pyrolysis was carried out over a temperature range of 350–600 °C using a pyroprobe microreactor coupled to a mass spectrometer (GC/MS). The best results, regarding overall volatile fraction, were observed when impregnation with 0.3% sulfuric acid was used prior to pyrolysis at 600 °C, resulting in around an 8.88-fold increase compared with untreated biomass. Nevertheless, the experimental conditions that favored the formation of our main chemical targets, such as levoglucosan, furfural and some phenols, were different. For instance, levoglucosan, furfural and eugenol increased by 21-, 10- and 22-fold, respectively, for biomass treated with HNO₃ (0.1%)/H₂SO₄ (0.2%) at 450 °C, whereas phenol and 4-vinylphenol increased by 35- and 14-fold at 500 °C. These findings can be considered satisfactory, highlighting the potential of the thermochemical conversion process as a valuable tool for the production of high-value chemicals from agricultural waste like rice husk. Full article

The mezcal industry in Mexico generates substantial volumes of vinasse, a waste product rich in organic material and bioactive compounds, yet its environmental impact and potential valorization in the food and biotechnological field remain underexplored. This study presents a comprehensive physicochemical and functional characterization of mezcal vinasse derived from mezcal production, including antioxidant activity and cytotoxicity assessment. Proximate analysis revealed high moisture content (96%) and a carbohydrate-rich profile (87.58% dry basis), with notable fiber fractions predominantly composed of insoluble dietary fiber (9.10% dry basis). Low-molecular-weight carbohydrate analysis identified fructose (60.46%) and glucose (10.48%) as the major components, and the hydrolyzed sample showed a monomeric profile with arabinose (31.98%) and glucose (24.14%) as the predominant sugars. Vinasse was found to provide antioxidant activity, as assessed by DPPH (296.3 µmol TE/g) and ABTS (465.3 µmol TE/g) colorimetric assays. Undesirable and antinutritional compounds such as tannins (15.3 mg catechin/g), oxalates (14.6 mg sodium oxalate/g), hydroxymethyl furfural (HMF) (3830.0 mg/L), and furfural (160.0 mg/L) were also quantified, highlighting potential environmental and nutritional concerns due to its mutagenic character at high concentrations. Despite these challenges, vinasse exhibited no cytotoxicity in Caco-2 cells at tested concentrations (25 to 100 mg/mL of phenolic extract), suggesting feasibility for further biotechnological applications. Full article

The homogeneous nature of L-proline organocatalysts restricts their application in aldol condensation due to poor recyclability and stability. Herein, L-proline was heterogenized by ionic intercalation into Mg–Al layered double hydroxides (LDHs), yielding a series of proline-intercalated catalysts with tunable layer structures. Co-precipitation and memory-effect reconstruction strategies were employed to regulate interlayer spacing and proline loading. The resulting catalysts exhibited efficient performance in the aldol condensation of furfural with ketones under mild conditions. The reconstructed catalyst re-Mg₄Al₁P achieved a furfural conversion of 88.67% and a total product yield of 85.54% at room temperature, with product selectivity exceeding 95%. Structural characterizations confirmed that proline was stabilized within the LDH interlayers via R–COO—Mg electrostatic interaction while preserving the secondary amine active site. Mechanistic analysis indicated that the reaction proceeded through enamine- or enol-mediated pathways depending on water content, while the layered LDH framework imposed geometric confinement that suppressed side reactions. Catalyst deactivation in aqueous systems was mainly attributed to proline leaching rather than structural collapse. Full article

5-Methoxymethyl-2-furfural (MMF) serves as a crucial biobased platform molecule that can be transformed into various high-value chemicals and biobased polyester monomers. However, the current production of MMF still faces several challenges, such as low yield and prolonged reaction time. In this study, we prepared a series of amide-modified strongly acidic resin catalysts and discovered that they have a higher efficiency in converting fructose to prepare MMF in 1-Butyl-3-methylimidazolium chloride ([BMIM]Cl) and methanol. Among the synthesized catalysts, DB757-NMP demonstrated superior performance, achieving an MMF yield of approximately 61.5% under the optimized conditions, with a combined yield of HMF and MMF reaching about 66.6%. The catalyst formation mechanism was analyzed using FTIR, and NMR, confirming the transformation of proton between NMP and the sulfonic acid groups of the resin, which collectively promoted the conversion of fructose to MMF. In addition, we investigated main reasons for catalyst deactivation and successfully restored catalytic activity through regeneration. The regenerated catalyst could be reused for three times with only a slight decrease in MMF yield. The results suggested that DB757-NMP is a more sufficient and recyclable catalyst for the production of MMF from fructose. This work presented a simple and environmentally benign approach for the synthesis of MMF. Full article