Search Results (777)

Isoquercitrin, a monoglucoside form of quercetin, exhibits superior antioxidant, anti-inflammatory, and cardiovascular protective effects in comparison to its precursor, rutin. However, its natural abundance is limited. This study aimed to increase the functional value of Diospyros lotus leaf extract through enzymatic conversion of rutin to isoquercitrin using α-l-rhamnosidase and to evaluate the changes in biological activities after conversion. A sugar-free D. lotus leaf extract was prepared and subjected to enzymatic hydrolysis with α-l-rhamnosidase under optimized conditions (pH 5.5, 55 °C, and 0.6 U/mL). Isoquercitrin production was monitored via high-performance liquid chromatography. Antioxidant and anti-inflammatory activities were assessed using the 2,2-diphenyl-1-picrylhydrazyl radical scavenging and lipoxygenase (LOX) inhibition assays, respectively. The enzymatic reaction resulted in complete conversion of 30 mM rutin into isoquercitrin within 180 min, increasing isoquercitrin content from 9.8 to 39.8 mM. The enzyme-converted extract exhibited significantly enhanced antioxidant activity, with a 48% improvement in IC₅₀ value compared with the untreated extract. Similarly, LOX inhibition increased from 39.2% to 48.3% after enzymatic conversion. Both extracts showed higher inhibition than isoquercitrin alone, indicating synergistic effects of other phytochemicals present in the extract. This study is the first to demonstrate that α-l-rhamnosidase-mediated conversion of rutin to isoquercitrin in D. lotus leaf extract significantly improves its antioxidant and anti-inflammatory activities. The enzymatically enhanced extract shows potential as a functional food or therapeutic ingredient. Full article

Plastic waste accumulation is one of the most pressing environmental challenges of the 21st century, owing to the widespread use of synthetic polymers and the limitations of conventional recycling methods. Among available strategies, chemical upcycling via depolymerization has emerged as a promising circular approach that converts plastic waste back into valuable monomers and chemical feedstocks. This article provides an in-depth narrative review of recent progress in the upcycling of major plastic types such as PET, PU, PS, and engineering plastics through thermal, chemical, catalytic, biological, and mechanochemical depolymerization methods. Each method is critically assessed in terms of efficiency, scalability, energy input, and environmental impact. Special attention is given to innovative catalyst systems, such as microsized MgO/SiO₂ and Co/CaO composites, and emerging enzymatic systems like engineered PETases and whole-cell biocatalysts that enable low-temperature, selective depolymerization. Furthermore, the conversion pathways of depolymerized products into high-purity monomers such as BHET, TPA, vanillin, and bisphenols are discussed with supporting case studies. The review also examines life cycle assessment (LCA) data, techno-economic analyses, and policy frameworks supporting the adoption of depolymerization-based recycling systems. Collectively, this work outlines the technical viability and sustainability benefits of depolymerization as a core pillar of plastic circularity and monomer recovery, offering a path forward for high-value material recirculation and waste minimization. Full article

The rising demand for sustainable protein is driving interest in insects as a raw material for advanced food ingredients. This review collates and critically analyses over 300 studies on the conversion of crickets, mealworms, black soldier flies, and other farmed species into powders, protein isolates, oils, and chitosan-rich fibers with targeted techno-functional roles. This survey maps how thermal pre-treatments, blanch–dry–mill routes, enzymatic hydrolysis, and isoelectric solubilization–precipitation preserve or enhance the water- and oil-holding capacity, emulsification, foaming, and gelation, while also mitigating off-flavors, allergenicity, and microbial risks. A meta-analysis shows insect flours can absorb up to 3.2 g of water g⁻¹, stabilize oil-in-water emulsions for 14 days at 4 °C, and form gels with 180 kPa strength, outperforming or matching eggs, soy, or whey in specific applications. Case studies demonstrate a successful incorporation at 5–15% into bakery, meat analogs and dairy alternatives without sensory penalties, and chitin-derived chitosan films extend the bread shelf life by three days. Comparative life-cycle data indicate 45–80% lower greenhouse gas emissions and land use than equivalent animal-derived ingredients. Collectively, the evidence positions insect-based ingredients as versatile, safe, and climate-smart tools to enhance food quality and sustainability, while outlining research gaps in allergen mitigation, consumer acceptance, and regulatory harmonization. Full article

Eco-enzymatic stoichiometry provides a basis for understanding soil ecosystem functions, with implications for land management and ecological protection. Long-term climatic factors and human interferences have caused significant land-use transformations in the Qinghai–Tibet Plateau region, affecting various ecological functions, such as soil nutrient cycling and chemical element balance. It is currently unclear how large-scale land-use conversion affects soil ecological stoichiometry. In this study, 763 soil samples were collected across three land-use types: farmland, grassland, and forest land. In addition, changes in soil physicochemical properties and enzyme activity and stoichiometry were determined. The soil available phosphorus (SAP) and total phosphorus (TP) concentrations were the highest in farmland soil. Bulk density, pH, SAP, TP, and NO₃⁻-N were lower in forest soil, whereas NH₄⁺-N, available nitrogen, soil organic carbon (SOC), available potassium, and the soil nutrient ratio increased. Land-use conversion promoted soil β-1,4-glucosidase, N-acetyl-β-glucosaminidase, and alkaline phosphatase activities, mostly in forest soil. The eco-enzymatic C:N ratio was higher in farmland soils but grassland soils had a higher enzymatic C:P and N:P. Soil microorganisms were limited by P nutrients in all land-use patterns. C limitation was the highest in farmland soil. The redundancy analysis indicated that the ecological stoichiometry in farmland was influenced by TN, whereas grass and forest soils were influenced by SOC. Overall, the conversion of cropland or grassland to complex land-use types can effectively enhance soil nutrients, enzyme activities, and ecosystem functions, providing valuable insights for ecological restoration and sustainable land management in alpine regions. Full article

This study proposes an integrated framework for sustainable tropical agriculture by combining biochemical waste valorization with spatial carbon footprint estimation in ‘Phulae’ pineapple production. Peel and eye residues from fresh-cut processing were enzymatically converted into rare sugar, achieving average conversion efficiencies of 35.28% for peel and 37.51% for eyes, with a benefit–cost ratio of 1.56 and an estimated unit cost of USD 0.17 per gram. A complementary zero-waste pathway produced functional gummy products using vinegar fermented from pineapple eye waste, with the preferred formulation scoring a mean of 4.32 out of 5 on a sensory scale with 158 untrained panelists. For spatial carbon modeling, the Bare Land Referenced Algorithm (BRAH) and Otsu thresholding were applied to multi-temporal Sentinel-2 and THEOS imagery to estimate plantation age, which strongly correlated with field-measured emissions (r = 0.996). This enabled scalable mapping of plot-level greenhouse gas emissions, yielding an average footprint of 0.2304 kg CO₂ eq. per kilogram of fresh pineapple at the plantation gate. Together, these innovations form a replicable model that aligns tropical fruit supply chains with circular economy goals and carbon-related trade standards. The framework supports waste traceability, resource efficiency, and climate accountability using accessible, data-driven tools suitable for smallholder contexts. By demonstrating practical value addition and spatially explicit carbon monitoring, this study shows how integrated circular and geospatial strategies can advance sustainability and market competitiveness for the ‘Phulae’ pineapple industry and similar perennial crop systems. Full article

Esterification is a key transformation in the production of lubricants, pharmaceuticals, and fine chemicals. Conventional processes employing homogeneous acid catalysts suffer from limitations such as corrosive byproducts, energy-intensive separation, and poor catalyst reusability. This review provides a comprehensive overview of heterogeneous catalytic systems, including ion exchange resins, zeolites, metal oxides, mesoporous materials, and others, for improved ester synthesis. Recent advances in membrane-integrated reactors, such as pervaporation and nanofiltration, which enable continuous water removal, shifting equilibrium and increasing conversion under milder conditions, are reviewed. Dual-functional membranes that combine catalytic activity with selective separation further enhance process efficiency and reduce energy consumption. Enzymatic systems using immobilized lipases present additional opportunities for mild and selective reactions. Future directions emphasize the integration of pervaporation membranes, hybrid catalyst systems combining biocatalysts and metals, and real-time optimization through artificial intelligence. Modular plug-and-play reactor designs are identified as a promising approach to flexible, scalable, and sustainable esterification. Overall, the interaction of catalyst development, membrane technology, and digital process control offers a transformative platform for next-generation ester synthesis aligned with green chemistry and industrial scalability. Full article

The functional role of MAPKK genes in potato (Solanum tuberosum L.) under high-temperature stress remains unexplored, despite their critical importance in stress signaling and yield protection. We characterized StMAPKK1, a novel group D MAPKK localized to plasma membrane/cytoplasm. Quantitative real-time polymerase chain reaction (qRT-PCR) revealed cultivar-specific upregulation in potato (‘Atlantic’ and ‘Desiree’) leaves under heat stress (25 °C, 30 °C, and 35 °C). Transgenic lines overexpressing (OE) StMAPKK1 exhibited elevated antioxidant enzyme activity, including ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD), mitigating oxidative damage. Increased proline and chlorophyll accumulation and reduced oxidative stress markers, hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), indicate improved cellular redox homeostasis. The upregulation of key antioxidant and heat stress-responsive genes (StAPX, StCAT1/2, StPOD12/47, StFeSOD2/3, StMnSOD, StCuZnSOD1/2, StHSFA3 and StHSP20/70/90) strengthened the enzymatic defense system, enhanced thermotolerance, and improved photosynthetic efficiency, with significant improvements in net photosynthetic rate (Pn), transpiration rate (E), and stomatal conductance (Gs) under heat stress (35 °C) in StMAPKK1-OE plants. Superior growth and biomass (plant height, plant and its root fresh and dry weights, and tuber yield) accumulation, confirming the positive role of StMAPKK1 in thermotolerance. Conversely, RNA interference (RNAi)-mediated suppression of StMAPKK1 led to a reduction in enzymatic activity, proline content, and chlorophyll levels, exacerbating oxidative stress. Downregulation of antioxidant-related genes impaired ROS scavenging capacity and declines in photosynthetic efficiency, growth, and biomass, accompanied by elevated H₂O₂ and MDA accumulation, highlighting the essential role of StMAPKK1 in heat stress adaptation. These findings highlight StMAPKK1’s potential as a key genetic target for breeding heat-tolerant potato varieties, offering a foundation for improving crop resilience in warming climates. Full article

Uncaria rhynchophylla, a medicinal plant extensively used in traditional Chinese medicine, is an important plant source of terpenoid indole alkaloids (TIAs), but the mechanism of TIA biosynthesis at molecular level remains unclear. Geraniol synthase (GES) serves as a crucial enzyme in catalyzing the formation of geraniol from geranyl pyrophosphate (GPP) in various plants, but the functional characterization of the GES gene in U. rhynchophylla has not been investigated. In this study, a GES was identified and characterized through genome mining and bioinformatic analysis. Functional validation was performed via a protein catalysis experiment, transient expression in Nicotiana benthamiana, and methyl jasmonate (MeJA) induction experiments. The full-length UrGES gene was 1761 bp, encoding a protein product of 586 amino acids with an estimated 67.5 kDa molecular weight. Multiple sequence alignments and phylogenetic analysis placed UrGES within the terpene synthase g (TPS-g) subfamily, showing high similarity to known GESs from other plants. Enzymatic assays confirmed that recombinant UrGES catalyzed GPP conversion to a single product of geraniol. The transient expression of UrGES resulted in geraniol accumulation in N. benthamiana, further confirming its function in vivo. UrGES expression was observed in leaves, stems, and roots, where leaves had the highest transcript levels. Moreover, MeJA treatment significantly upregulated UrGES expression, which positively correlated with an increase in alkaloid content. This study functionally characterizes UrGES as a geraniol synthase in U. rhynchophylla, contributing to the current knowledge of the TIA biosynthetic pathway. These findings may offer insights for future metabolic engineering aiming to enhance TIA yields for pharmaceutical and industrial applications. Full article

Anaerobic acidogenic fermentation presents a promising approach for sustainable carbon emission mitigation in livestock waste management, addressing critical environmental challenges in agriculture. This study systematically investigated the synergistic effects of composting-assisted pretreatment coupled with micro-aeration and methanogenesis suppression to enhance volatile fatty acid (VFA) production from swine manure supplemented with wheat straw, valorizing agricultural waste while reducing greenhouse gas emissions. The experimental protocol involved sequential optimization of pretreatment conditions (12 h composting followed by 10 min thermal pretreatment at 85 °C), operational parameters (300 mL micro-aeration and 30 mmol/L 2-bromoethanesulfonate (BES) supplementation), and their synergistic integration. The combined strategy achieved peak VFA production (5895.92 mg/L, p < 0.05), with butyric acid constituting the dominant fraction (2004.42 mg/L, p < 0.05). Enzymatic analysis demonstrated significantly higher activities of key hydrolytic enzymes (protease, α-glucosidase) and acidogenic enzymes (butyrate kinase, acetate kinase) in the synergistic treatment group compared to individual BES-supplemented or micro-aeration-only groups (p < 0.05). This integrated approach provides a technically feasible and environmentally sustainable pathway for circular resource recovery, contributing to low-carbon agriculture and waste-to-value conversion. Full article

Background: Heparan sulfate (HS) is widely implicated as a receptor for Chlamydia cell attachment and infectivity. However, the enzymatic modification of HS modified by the 3-O sulfotransferase-3 (3-OST-3) enzyme in chlamydial cell entry remains unknown. Methodology: To rule out the possibility that host cell 3-O sulfated heparan sulfate (3-OS HS) plays a significant role in C. muridarum entry, a Chinese hamster ovary (CHO-K1) cell model lacking endogenous 3-OST-3 was used. In addition, we further tested the efficacy of the phage-display-derived cationic peptides recognizing heparan sulfate (G1 peptide) and the moieties of 3-O sulfated heparan sulfate (G2 peptide) against C. muridarum entry using human cervical adenocarcinoma (HeLa 229) and human vaginal epithelial (VK2/E6E7) cell lines. Furthermore, molecular dynamics simulations were conducted to investigate the interactions of the Chlamydia lipid bilayer membrane with the G1 and G2 peptides, focusing on their binding modes and affinities. Results: The converse effect of 3-OST-3 expression in the CHO-K1 cells had no enhancing effect on C. muridarum entry. The G2 peptide significantly (>80%) affected the cell infectivity of the elementary bodies (EBs) at all the tested concentrations, as evident from the reduced fluorescent staining in the number of inclusion bodies. The observed neutralization effect of G2 peptide on C. muridarum entry suggests the possibility of sulfated-like domains being present on the EBs. In addition, data generated from our in silico computational structural modeling indicated that the G2 peptide ligand had significant affinity towards the C. muridarum lipid bilayer. Conclusions: Taken together, our findings show that the pretreatment of C. muridarum with 3-O sulfated heparan sulfate recognizing G2 peptide significantly prevents the entry of EBs into host cells. Full article

In enzymatic reaction glucose detection chips, the enzyme can easily dislodge from the electrode, which harms both the chip and test stability. Additionally, enzyme activity significantly decreases at low temperatures. Consequently, immobilizing the enzyme at the appropriate substrate and ambient temperature is a critical step for improving the chip. To address this issue, an electrochemical detection chip was modified using the nanomaterial MXene, known for its large specific surface area, excellent adsorption, good dispersion, and high conductivity. Meanwhile, AgNO₃ solution was added to the Ti₃C₂T_x MXene nanosheet solution, and the AgNP@MXene material was prepared by heating in a water bath. This process further enhances photothermal conversion efficiency due to the localized surface plasmon resonance effect of silver nanoparticles and MXene. This MXene-based photothermally enhanced paper chip exhibits outstanding photothermal conversion performance and sensitive photoelectrochemical responsiveness, along with good cycling stability. Moreover, improved glucose detection sensitivity at low winter temperatures has been achieved, and the ambient temperature range of the paper chip has been expanded to 25–37 °C. Full article

This study investigates the structural effects of dilute acid and alkali treatments on cotton fibers, aiming to understand the influence of chemical pretreatment on cellulose morphology. Cotton samples were exposed to 1% sulfuric acid and 1% sodium hydroxide at 90 °C, and the resulting changes were evaluated using scanning electron microscopy and nonlinear optical imaging techniques. The results indicate that sulfuric acid causes significant fiber degradation, leading to fragmentation and reduced fiber thickness. In contrast, sodium hydroxide treatment results in a roughened, flaky surface while preserving the overall structural integrity, with fibers appearing fluffier and more accessible to enzymatic processes. Untreated cotton fibers maintained a smooth and uniform surface, confirming the chemical specificity of the observed changes. These findings are crucial for optimizing biomass pretreatment methods, demonstrating that dilute chemical treatments primarily affect macrostructural features without significantly disrupting the cellulose microfibrils. The study provides valuable insights for the development of efficient biorefining processes and sustainable bio-based materials, highlighting the importance of selecting appropriate chemical conditions to enhance enzymatic hydrolysis and biomass conversion while maintaining the core structure of cellulose. This research contributes to advancing the understanding of cellulose’s structural resilience under mild chemical pretreatment conditions. Full article

The enzymatic formation of kynurenic acid (KYNA), a neuromodulator metabolite of the kynurenine pathway (KP) of tryptophan metabolism, in the mammalian brain is widely attributed to kynurenine aminotransferase II (KATII). However, an alternative biosynthetic route, involving the conversion of D-kynurenine (D-KYN) to KYNA by D-amino acid oxidase (D-AAO), may play a role as well. In the present study, we first confirmed that purified D-AAO efficiently converted D-KYN—but not L-KYN—to KYNA. We then examined KYNA formation from D-KYN (100 µM) in vitro, using tissue homogenates from several human brain regions. KYNA was generated in all areas, with D-AAO-specific production being most effective by far in the cerebellum. Next tested in homogenates from rat cerebellum, KYNA neosynthesis was significantly reduced by D-AAO inhibition, whereas KATII inhibition had no effect. Finally, KYNA production was assessed by in vivo microdialysis in rat cerebellum. Local D-KYN perfusion, alone and in combination with inhibitors of D-AAO (kojic acid) or aminotransferases (AOAA), caused a substantive increase in extracellular KYNA levels. This effect was attenuated dose-dependently by micromolar concentrations of kojic acid, whereas co-perfusion of AOAA (1 mM) was ineffective. Together, our findings indicate that D-AAO should be considered a major contributor to KYNA production in the cerebellum, highlighting region-specific qualitative differences in cerebral KYNA metabolism. Full article

Icariside I, a bioactive flavonoid derivative derived from Herba epimedii, demonstrates better pharmacological properties compared to its precursor icariin. Enzymatic conversion of icariin to icariside I using α-L-rhamnosidase represents an efficient biotechnological approach. In this study, we characterized a GH78 family α-L-rhamnosidase from Dictyoglomus thermophilum (DthRha) with promising biocatalytic properties. The recombinant DthRha displayed optimal activity at 55 °C and pH 6.0, with remarkable thermostability (retaining > 80% activity after 1 h at 45–65 °C) and pH stability (pH 5.0–7.0). The kinetic parameters K_m, k_cat and k_cat/K_m values for pNPR of 0.44 mM, 7.99 s⁻¹ and 18.16 s⁻¹ mM⁻¹, respectively. Notably, DthRha exhibited good organic solvent tolerance, retaining > 50% activity after 4 h in 10% DMSO. Applied in a DMSO cosolvent system, DthRha achieved 92.3% conversion of icariin to icariside I within 4 h under optimized conditions. Interestingly, elevating the substrate concentration to 10 mM resulted in a consistently high icariin conversion of 95.8%. The enzymatic hydrolysis method can be applied to the industrial production of Icariside I. Furthermore, DthRha not only cleaves the α-1,2 glycosidic bond between glucoside and rhamnoside in compounds like naringin, but also exhibits tolerance to organic solvents, making it suitable for the hydrolysis of other poorly soluble flavonoids. Full article

Ornithine decarboxylase (ODC) is the rate-limiting enzyme in the biosynthesis of polyamines and plant alkaloids, including medicinal tropane alkaloids (TAs). Due to its key role, ODC has been utilized as an effective molecular tool in metabolic engineering. However, to date, only a limited number of plant ODCs have been characterized. Among the reported ODCs, Erythroxylum coca ODC (EcODC) exclusively has ODC activity, while Nicotiana glutinosa ODC (NgODC) exhibits dual ODC and lysine decarboxylase (LDC) activities. The potential LDC activity of ODCs from TA-producing plants remains unknown. Here, we characterized AlODC and DsODC from Anisodus luridus and Datura stramonium, along with two previously reported ODCs from Atropa belladonna (AbODC) and Hyoscyamus niger (HnODC), in Escherichia coli to investigate their enzyme kinetics and substrate specificity. Enzymatic assays revealed that both AlODC and DsODC catalyzed the conversion of ornithine to putrescine, confirming their ODC activity, with AlODC exhibiting a higher catalytic efficiency, comparable to established ODCs. Furthermore, all four ODCs also displayed LDC activity, albeit at significantly lower efficiency (<1% of ODC activity). This study provides a comprehensive analysis of the enzyme kinetics of ODCs from TA-producing plants, identifying promising candidate genes for metabolic engineering for the biomanufacturing of putrescine-derived alkaloids. Moreover, this is the first report of LDC activity in ODCs from Solanaceae TA-producing plants, shedding light on the evolutionary relationship between ODC and LDC. Full article