Retention Of Activity Research Articles

Oxidative stability of optimized nanostructured lipid carriers containing thymoquinone‐rich oil

AbstractLipid‐based nanodelivery systems are now widely used in the pharmaceutical and food industries to enhance the delivery of bioactive compounds by leveraging the properties of lipids. Nanostructured lipid carriers (NLC), as one of the lipid‐based nano‐delivery systems, employs a blend of solid and liquid lipids, which improves the solubility, stability, and bioavailability of bioactive substances. This study aimed to optimize the NLC containing thymoquinone‐rich oil (NLC‐TQO) formulation using the Box–Behnken design; assess its antioxidant activity and oxidative stability by measuring 2,2‐diphenyl−1‐picrylhydrazyl (DPPH) radical scavenging activity, thymoquinone (TQ), and tocopherol contents over 28‐day storage; and evaluate the impact of incorporating beta‐carotene as singlet oxygen quencher on the oxidative stability of the NLC‐TQO. The optimized formulation involved 4.16% lipids (glyceryl monostearate and TQO), 5.85% Tween 80 as the surfactant, and 8.20 min of ultrasonication. NLC formulations demonstrated better DPPH activity retention than the emulsions, with cold and dark storage conditions being the most effective for preserving antioxidant activity. TQ stability in the NLC was observed at elevated temperatures without light, with around 50% remaining intact. However, TQ degraded rapidly under light, almost entirely by day 7. Gamma‐tocopherol exhibited better stability than alpha‐tocopherol, especially under light. The addition of beta‐carotene enhanced NLC‐TQO's oxidative stability. These findings revealed the potential of the NLC formulation as an effective delivery system for TQ with better oxidative protection compared to emulsions, making it a promising option for pharmaceutical and food industry applications.

From Enzyme Encapsulation to Environmental Solutions: Photostable Laccase in Dopc Vesicles

AbstractOur results demonstrate that DOPC vesicles effectively encapsulate the laccase enzyme, maintaining its activity within the vesicles. Moreover, the substrate syringaldazine, a model compound for laccase activity studies, was able to permeate through the bilayer. Notably, encapsulated laccase exhibited significantly higher retention of enzymatic activity (REA) post‐irradiation compared to the free enzyme. In conclusion, both unilamellar and multilamellar vesicles provide substantial photoprotection for laccase against UVB light. This protective effect is attributed to the enzyme's confinement within a system that scatters high‐energy photons. Furthermore, the simplicity and ease of large‐scale production of multilamellar vesicles present an advantageous option for various applications, including bioremediation.

Effect of lipid-polysaccharide edible coatings on enhancing shelf life and quality of guava (Arka Kiran)

The physicochemical properties of guava (Arka Kiran) fruits were examined in relation to pre- and post-harvest treatments, both individually and in combination, using various edible compounds, including hexanal, chitosan, and salicylic acid. The fruits were treated with different concentrations of hexanal (2%), chitosan (1%), and salicylic acid (500 ppm) and assessed for various physico–chemical parameters. In the storage study, guava fruits treated with these edible compounds were stored under both ambient conditions (30°C ± 1°C) and cold storage conditions (10 ± 2°C). The fruits treated with 2% hexanal demonstrated the most significant improvements in quality-related parameters under cold storage and ambient conditions. The combination of pre-harvest spray and post-harvest treatments using 2% hexanal in cold storage significantly delayed physiological weight loss (24.55%), preserved total soluble solids (10.25 ºBrix), and maintained ascorbic acid content (135.05µg) by the 18th day of the storage period. Furthermore, pre-and post-harvest treatment with chitosan under cold storage conditions significantly enhanced the retention of antioxidant activity and phenolic content in guava fruit. Overall, the treatment with 2% hexanal proved to be the most effective in regulating physicochemical changes and improving the storage quality of guava fruits.

Improving enzyme immobilization: A new carrier-based magnetic polymer for enhanced covalent binding of laccase enzyme

In the quest for effective enzyme immobilization methods, this study focuses on synthesizing carrier-based magnetic polymer to enhance the covalent binding of T. versicolor laccase. Utilizing chitosan (CS) and alginate (ALG) composites, modified with Fe3O4 magnetic nanoparticles (MNPs), we aimed to improve the enzyme's stability, reusability, and performance under varying conditions. The ionic gelation method was employed to prepare CS-ALG and CS-ALG-Fe3O4 MNPs composites, resulting in an 84 % and 91 % immobilization efficiency. The immobilized enzyme demonstrated superior thermal stability, retaining 48 % activity for CS-ALG-laccase and 67 % for CS-ALG-Fe3O4 MNPs-laccase at 70 °C, compared to 29 % for the free enzyme. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the composites, revealing significant morphological changes and successful enzyme integration. Kinetic studies indicated that immobilization increased the Vmax to 141 μmol/min for CS-ALG-laccase and 111 μmol/min for CS-ALG-Fe3O4 MNPs-laccase, while slightly reducing substrate affinity (Km) to 1.42 mM−1 and 1.32 mM−1, respectively. The immobilized laccase retained higher activity after ten reaction cycles (81 % activity for CS-ALG-Fe3O4 MNPs-laccase) and during prolonged storage (75 % activity retention), showcasing its potential for industrial applications. Additionally, the enzyme exhibited increased resistance to various organic solvents, enhancing its practical utility.

In-situ aqueous phase encapsulation immobilized lipase assisted by acidic ionic liquids for the synthesis of isoamyl acetate

In this study, two acidic ionic liquids were innovatively selected to replace traditional acetic acid as catalysts and templates for the preparation of covalent organic frameworks (COFs) materials in aqueous phase at room temperature. At the same time, the synthesized COFs carrier achieved in-situ encapsulation and immobilization of Candida rugosa lipase (CRL) in aqueous phase at room temperature. The optimum immobilized lipases COF-COOH-M and COF-SO3H-M were obtained by adjusting the reaction conditions. Their enzyme loadings were 210.17 mg/g and 258.47 mg/g, respectively, and the specific activity retention compared to free lipase was 67.11% and 78.42%, respectively. The carrier and immobilized lipase were characterized by FT-IR, XRD, BET and TG. The catalytic performance and operational stability of the immobilized lipase were investigated. The results showed that both immobilized lipases showed better stability than free lipases, and COF-SO3H-M had the best performance. The relative activity retention of COF-SO3H-M after incubation at 60 °C for 60 minutes was 4.35 times that of free lipase. After 28 days of storage at 4 °C, the relative activity of COF-SO3H-M remained 75.10%, while that of free lipase was only 24.61%. The COF-SO3H-M was applied as biocatalyst for isoamyl acetate preparation at 50 °C for 7 hours, and the yield of isoamyl acetate was as high as 86.94%, which was 22.12% higher than that of free lipase.

Enhancing the Stability and Activity of Enzymes through Layer-by-Layer Immobilization with Nanocomposite Hydrogel

In this study, a layer-by-layer immobilization strategy was meticulously designed to enhance the stability and activity of enzymes. The approach utilized calcium magnesium carbonate (CaMg(CO3)2) nanoparticles as an immobilization template for abundant binding sites for enzyme attachment but also provide a microenvironment conducive to maintaining enzyme conformation with their unique physicochemical properties. Subsequently, the polymerization of poly(2-hydroxyethyl methacrylate) (pHEMA) to form the nanocomposite hydrogel poly(2-hydroxyethyl methacrylate)-calcium magnesium carbonate (pHEMA-CaMg(CO3)2) introduces a layered architecture, enabling the spatially immobilized enzymes. The pHEMA-CaMg(CO3)2 nanocomposite hydrogel immobilized carbonyl reductase retained over 80% catalytic activity after one month and 81% after 10 cycles of aryl ketone reduction. Similarly, the immobilized lipase within the pHEMA-CaMg(CO3)2 nanocomposite hydrogel exhibited over 80% catalytic activity after one month and demonstrated an impressive 85% activity retention after 10 reuse cycles in glycerol trioctanoate hydrolysis reactions. The FTIR spectra and energy-dispersive X-ray (EDX) spectroscopy mapping showed after multiple repeated uses indicating that the secondary structure of the immobilized enzyme was well preserved, further validating the superiority of our immobilization strategy in safeguarding enzymes integrity and functionality over extended periods and repeated applications.

Testing of Marine Fouling‐Inhibiting Enzymes in a Water‐Based Methacrylate Polymer Matrix

AbstractCommonly used antifouling coatings rely on the continuous release of biocidal ingredients and are becoming increasingly restricted by legislation. The resulting demand for nonbiocidal technologies involves the search for alternative ingredients and in particular enzymes have received increasing attention. While screening of the antifouling activity of active compounds in solution is well established, the analysis of their activity and in particular anti‐biofouling activity when embedded into a coating and even more so in an activated leachate layer is very demanding. Among the challenges is the even distribution throughout the coating and retention of the enzymatic activity. Here a water‐based HEMA‐methacrylate polymer matrix is presented that aims to mimic the leachate layer and to incorporate active compounds. This technology is used to incorporate several hydrolytically active enzymes‐cellulase, protease, and lipase‐in a grafting‐through approach. After immersion, the enzymes are released in a controlled way during several days. The enzyme‐loaded polymer films reduced the attachment of fouling organisms through a combination of their hydrophilic nature and activity of the enzymes. The active contribution of the enzymes became visible in a significant suppression of the accumulation of diatoms and green algal spores compared to the enzyme‐free and heat‐denatured control coatings.

Integrated Catalyst ZnNC⊂PtZn for High‐performance Ethanol Electrooxidation and DEFC

We report here an electrocatalyst that exhibits superior performance in the electrooxidation of ethanol. The reactive centers of the catalyst have a nest‐type configuration with outer Zn‐NxC nest covering inner PtZn intermetallic compound nanoparticle loaded on carbon support (ZnNC⊂PtZn/C). The high‐energy stepped facets of the inner PtZn nanoparticle confined and shaped by the outer Zn‐NxC nest is highly active for the critical C‐C bond cleavage of ethanol in oxidation, confirmed by experimental characterizations and density functional theory calculations. The catalyst shows a rare high‐performance and demonstrates a mass activity of 3.7 A mgPt‐1 and a Faradaic efficiency of 78.2%, following the C1 pathway of reaction and the retention of initial activity remains 97% after 5,000 cycles. The unique configuration, also mitigating the concentration polarization, endows the catalyst with innate ethanol electrooxidation property by inner‐outer synergic interactions, leading to unexpected power output of an acidic direct ethanol fuel cell.

Potted garden pea grown in presence of pre-emergence herbicides: Impacts on soil enzymes and human health

Pre-emergence herbicide residues in pea cultivation can pose significant health risks to nontarget organisms, including humans. To assess the impact of these residues on soil and human health, garden peas were grown in an agricultural soil (MAT) and potting mix (POM) treated with dimethenamid-P, metazachlor, and pyroxasulfone. Dehydrogenase activity in MAT soil was not significantly affected by these herbicides. However, in POM, herbicide application resulted in significantly higher dehydrogenase levels, likely due to the higher organic matter content promoting microbial activity and moisture retention. In contrast, phosphatase activity levels remained relatively consistent across untreated and treated samples of both MAT and POM. Herbicide residues in pea pods, shoots and roots were measured to evaluate potential human health hazards. The detected residue levels were at or above the European Union’s maximum residue levels. The calculated non-cancer acute health hazard index of (aHI <100 %) and hazard quotient of (HQ <1) suggested that consuming peas grown in potting medium treated with these herbicides at recommended doses does not pose a health hazard to humans. This study is the first to provide insights into the environmental impact of pre-emergence herbicide residues in soil, aiding the development of safer and more sustainable vegetable farming practices.

Antimicrobial Peptide SAAP-148-Functionalized Hydrogels from Photocrosslinkable Polymers with Broad Antibacterial Activity.

Antimicrobial peptides (AMPs) are promising alternatives to traditional antibiotics for treating skin wound infections. Nonetheless, their short half-life in biological environments restricts clinical applicability. Covalent immobilization of AMPs onto suitable substrates offers a comprehensive solution, creating contact-killing surfaces with long-term functionality. Here, a copolymer of poly[(hydroxy ethyl acrylamide)-co-(4-benzophenone acrylamide)-co-(pentafluorophenyl acrylate)-co-(ECOSURF EH-3 acrylate)], in short poly(HEAAm-co-BPAAm-co-PFPA-co-EH3A), is synthesized by free radical polymerization. Subsequent modification of active ester groups with the amine groups of SAAP-148, results in a copolymer, that is non-cytotoxic to human lung fibroblasts. UV photocrosslinking of the benzophenone units yields a polymer network that forms a hydrogel after swelling with aqueous medium. Both the SAAP-148-modified polymer in solution and the photocrosslinked hydrogels show good antimicrobial activity against strains of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii, including multidrug-resistant strains, frequently found in wound infections. The covalent attachment of SAAP-148 prevents leaching, ensuring sustained antimicrobial activity for at least 48 h in diluted human blood plasma and 14 days in PBS. This prolonged retention of antimicrobial activity in human blood plasma significantly enhances its clinical potential. Overall, this study shows the potential of the AMP-functionalized photocrosslinkable polymer as antimicrobial wound dressings, providing an effective alternative to antibiotics.

Ultra-High Activity and Durability of Low-Platinum Fuel Cells Enabled by Encapsulation of L10-PtCo and L12-Pt3Co Intermetallic Compounds.

Developing high-performance, durable, and ultralow-loading platinum (Pt) catalysts for the oxygen reduction reaction (ORR) is crucial for advancing fuel cells. Here, a novel structured alloy catalyst is reported, characterized by Pt-Co intermetallic compounds with a Pt-skin, encapsulated by a covalent organic framework (COF) derived carbon support. This unique structure, combining alloy-induced strain effects and protective encapsulation, leads to exceptional catalytic activity and stability at an ultralow Pt loading of 0.02 mgPt cm-2. To be specific, this catalyst exhibits peak power densities of 1.77W cm-2 in fuel cell tests. It demonstrates a state-of-the-art mass activity of 2.15 A mgPt -1 (@0.9 V), which is 5.38 times that of commercial Pt/C (0.40 A mgPt -1). More importantly, the fuel cell assembled with this novel catalyst displays exceptional durability, with a voltage degradation of only 9.9mV after 100,000 cycles at 0.8 A cm-2 and a mass activity retention of 85% (1.83 A mgPt -1), far exceeding the 2025 initial mass activity (MA) target (0.44 A mgPt -1) of DOE by 4.2 times. Notably, the current density at 0.6 V under hydrogen-air conditions shows only a slight decline after more than 230 h.

Conformational and processing properties of a high-active ingredient involving soy protein isolates bound with anthocyanins and its application in cake baking

Soybean protein is of plant origin and is commonly appropriate for improving the processing characteristics of foods. This study aimed to explore a novel functional ingredient that contained soybean protein isolate (SPI) and blueberry anthocyanins (BANs). The spatial conformation and secondary structure of SPI-BANs complexes were analyzed using circular dichroism and fluorescence spectroscopy, the processing properties were investigated as well as the retention of antioxidant activity during thermal treatments. Results showed that the contents of free sulfhydryl and free amino groups in complexes increased to 3.50 and 1.19 folds than those of SPI, respectively, while the surface hydrophobicity decreased by 74.23%. Compared with SPI, the BANs-modified SPI had a smaller particle size of 29.12 nm and a lower zeta-potential of -8.73 mV and on the other hand, the complexes possessed higher solubility (83.08%) and foaming and emulsifying properties (115.08% and 54.03 m2/g). After fortification with SPI-BANs, the baking loss rate and adhesiveness of chiffon cake were reduced by 10.82% and improved to 0.24 N.mm, respectively. The high antioxidant activities of SPI-BANs under heat led to the cake’s bioactivities largely enhanced by 1.99 ~ 12.71 folds, being 345.19 µg Trolox/g for the DPPH radical scavenging activity. This study developed the functional food ingredients as antioxidants and a substitute for animal-based proteins in bakery products, which was safe and sustainable by using the dietary components from plant resources.Graphical

Catalase-peroxidase StKatG2 from Salinicola tamaricis: a versatile Mn(II) oxidase that decolorizes malachite green.

Manganese (Mn) oxidation processes have garnered significant attention recently due to their potential for degrading organic pollutants. These processes are primarily catalyzed by Mn(II) oxidases. Salinicola tamaricis F01, an endophytic bacterium derived from wetland plants, has demonstrated Mn(II)-oxidizing capacity. In this study, a catalase-peroxidase, StKatG2, was cloned and overexpressed in Escherichia coli from the strain F01. The purified recombinant StKatG2 exhibited Mn(II)-oxidizing activity with K m and K cat values of 2.529 mmol/L and 2.82 min-1, respectively. Optimal catalytic conditions for StKatG2 were observed at pH 7.5 and 55°C, with 45.1% activity retention after an 8-h exposure to 80°C. The biogenic manganese oxides produced by StKatG2 exhibited mixed-valence states with Mn(II), including Mn(III), Mn(IV), and Mn(VII). Furthermore, StKatG2 demonstrated superior decolorization efficiency for malachite green (MG), achieving decolorization rates of 73.38% for 20 mg/L MG and 60.08% for 50 mg/L MG, while degrading MG into 4-(dimethylamino)benzophenone. Therefore, the catalase-peroxidase StKatG2 exhibits multifunctionality in Mn(II)-oxidizing activity and has the potential to serve as an environmentally friendly enzyme for MG removal.

Surface Reconstruction of Single-Twinned AgPdIr Nanoalloy during the Formate Oxidation and Dehydrogenation Reactions.

Formate has emerged as a promising energy carrier to generate electrons via formate oxidation reaction (FOR) and hydrogen via formate dehydrogenation reaction (FDR), and it is desirable but difficult to design a novel bifunctional (electro)catalyst to improve reaction kinetics. Herein, we construct the single-twinned AgPdIr (t-AgPdIr) nanoalloy to improve the catalytic activity and stability for the formate oxidation and dehydrogenation processes. The t-AgPdIr nanoalloy, characterized by a distinctive twinned structure with strains and a downshift of the d-band center, demonstrates an improved peak current density of 4.6 A·mgPd -1, a diminished onset potential of 0.45 V, a superior activity retention of 55.7% after 600 cycles, and a current density of 0.73 A·mgPd -1 following potentiostatic polarization for 3600 s. Additionally, the t-AgPdIr catalyst shows an enhanced turnover frequency value of 407.3 h-1, a higher volume of generated H2 gas up to 51.8 mL after 120 min of reaction, and an activity recovery of 90.7% after five reaction cycles. Impressively, compared with the as-prepared nanoalloy, the postreaction catalyst shows a stable strain state along the twin boundaries and a surface segregation of Pd and Ir elements after the formate oxidation and dehydrogenation reactions.

Synergistic effects of CNT-bridged dual-phase MoS2 on MXene as a ternary hybrid electrode for rapid sensing of chloramphenicol in aqueous media

The fabrication of a hybridized electrochemical sensor denoted CNT/MoS2/MXene for chloramphenicol (CAP) detection is described based on growing MoS2 nanoflakes on stacked Ti3C2Tx MXene and bridging the structure obtained with carbon nanotubes (CNTs). Herein, we introduce an acid-etched stacked Ti3C2Tx MXene as an interlayered structure to accommodate solvothermally grown layered MoS2 and a bridged CNT network for the efficient electrocatalytic sensing of CAP. The successful growth of MoS2 on the MXene surface prevented restacking of layered MXene and increased conductivity. Interconnected CNTs over the MoS2 nanoflake array served as an electron transport highway, accelerating the electron transport pathway and maintaining the structural stability of the MXene/MoS2 heterostructure. Morphologically, CNT/MoS2/MXene was found to have a functionalized multilayered structure and to have a greater electron transfer rate, and a larger electrochemically active surface area than the binary feature. Modifying the surface area of MXene with MoS2 and CNTs synergistically enhanced the transportation of kinetic barrier electrons and well-defined the redox cycle in the ferricyanide system. Further, the electrochemical detection of CAP using a CNT/MoS2/MXene electrode by cyclic voltammetry (CV) produced greater electrochemical responses than bare GCE, MXene, CNT-MoS2, and MoS2-MXene. In addition, scanning rates, the effects of different concentrations, and pH electrolyte tests showed that the GCE-CNT/MoS2/MXene electrode was suitable for the electrochemical sensing of CAP. Amperometric response, as determined by i-t profiles, showed the CNT/MoS2/MXene electrode had superior electrochemical sensing performance for CAP detection, a wide linear range (8 to 152 nM), a remarkably low detection limit (0.32 nM), a high sensitivity of 14.22 μA nM−1cm−2, and superior stability (96 % activity retention after four weeks). The synergistic effect of the ternary three-dimensional assembly with CNT bridging over hierarchical MoS2/MXene increased surface-active sites and electron transportation rates and enhanced CAP detection performance. Moreover, the proposed sensor demonstrated high selectivity and satisfactory recovery for milk, eye drops, and pork.

Ultrasonic Fabrication of Catechin Nanoemulsions from Green Tea with Enhanced Stability and Antioxidant Activity Optimized by Box-Behnken Design

Nanoemulsions are emulsions, either O/W (oil in water) or W/O (water in oil), with droplet diameters typically ranging from 50 to 1,000 nm. Research indicates that nanoemulsions are highly effective in enhancing the bioavailability, bioactivity, digestibility, stability, safety, quality and sensory attributes of food components. The study aimed to determine the optimum formulation and ultrasonic condition for fabricating catechin nanoemulsion (Ca-NE) from green tea with improved physical stability and antioxidant activity using response surface methodology. The effects of Medium Chain Triglyceride oil concentration (7.5 - 12.5 % w/w), Tween® 80 concentration (1 - 5 % w/w) and sonication time (5 - 15 min) on the droplet size, polydispersity index (PDI) and antioxidant activity presented by DPPH value of the Ca-NE were investigated using Box-Behnken design (BBD). The results found that droplet size and antioxidant activity of the Ca-NE were significantly (p &lt; 0.05) affected by the proposed parameters, whereas the PDI value was slightly affected by those factors. The BBD results suggested that the Ca-NE fabrication condition was optimized with 7.5 % (w/w) oil concentration, 5 % (w/w) Tween® 80 concentration and a sonication time of 10.87 min. The optimum nanoemulsion showed good physical stability in terms of droplet size and PDI and had higher antioxidant activity than unencapsulated catechins when stored at 4 and 30 °C for 90 days. This study showed that catechin nanoemulsions fabricated by ultrasonication had good stability and antioxidant activity and, hence, had high potential for food and beverage applications in the food industry. HIGHLIGHTS The optimum nanoemulsion had good physical stability regarding droplet size and PDI when stored at 4 and 30 °C for 90 days. The ultrasonic fabrication of Ca-NE results in better retention of antioxidant activity than unencapsulated catechins. The ultrasonic fabrication provided the Ca-NE with good stability and high antioxidant activity. The results suggest that the obtained nanoemulsion of catechins has great potential in food or pharmaceutical applications. GRAPHICAL ABSTRACT

Chitin membrane for efficient laccase immobilization and synergistic removal of 17α-ethynylestradiol from water-based solutions

A unique chitin–laccase membrane was fabricated as an environmentally friendly biocatalytic platform, utilizing 1-butyl-3-methylimidazolium acetate as the solvent for chitin. Observations using scanning electron microscopy showed that the chitin-laccase membrane possessed a uniform and densely packed structure. Based on the presence of FT-IR signals at 1020 cm−1 and changes in the intensity of signals at 1540 cm−1 and 1645 cm−1, the effectiveness of laccase immobilization was confirmed. FT-IR mapping revealed that the enzyme is evenly distributed on the surface of the membrane. The catalytic activity of the native enzyme and laccase immobilized using the membrane was determined based on a model reaction, and the retention of high activity was confirmed using real solutions. Laccase immobilized using the chitinous membrane retained over 60 % of its initial activity after 30 days of storage at 4 °C. By contrast, the free enzyme retained <40 % of its initial activity. Moreover, the activity of chitin-laccase system remained at 85 % after 5 cycles. This novel chitin–laccase combination was tested in the 17α-ethynylestradiol (EE2) removal from water-based solutions. It was found that EE2 underwent synergistic degradation through concurrent adsorption and biocatalytic transformation, with enzymatic conversion as the dominant mechanism.

Precise Immobilization Strategy Combined with Rational Design to Improve β-Agarase Stability.

Recently, the orientational immobilization of enzymes has attracted extensive attention. In this study, we report the development of a strategy combined with rational design to achieve precise site-specific covalent immobilization of β-agarase. We first rationally screened six surface sites that can be mutated to cysteine by combining molecular dynamics simulation and energy calculation. Site-specific immobilization was successfully achieved by Michael addition reaction of mutant enzymes and maleimide-modified magnetic nanoparticles (MAL-MNPs). The enzyme activity retention rate of R66C-MAL-MNPs and K588C-MAL-MNPs was greater than 96%. The thermal deactivation kinetics study revealed that the site-specific immobilization strategy significantly improved the thermal stability of Aga50D, resulting in a substantial increase in its antidenaturation activity at elevated temperatures, and the highest t1/2 of the immobilized mutant enzymes was increased by an impressive 21.25-fold at 40 °C. The immobilized mutant enzymes also showed significantly enhanced tolerance to metal ions and organic reagents. For instance, all of the immobilized enzymes maintained over 90% of their enzymatic activity in the 50% (v/v) acetone/water solution. The present work may pave the way for the design of precisely immobilized enzymes, which can help promote green manufacturing.

Effect of Different Drying Methods on Colour, Total Phenolic Content, Flavonoid Content, and Antioxidant Activity Retention of Strobilanthes crispus Leaves

Strobilanthes crispus, a medicinal herb, is recognised for its abundant phytochemicals, notably in its leaves, contributing to its high antioxidant activity. However, the crucial step of drying, aimed at extending shelf life, can impact the stability of these bioactive compounds. This study evaluates the impact of different drying methods, which include oven, microwave, freeze drying, and air drying, on the colour, phenolic and flavonoid content, and antioxidant activities of S. crispus leaves. The colour analysis of the fresh and dried leaves was assessed using the chromameter. Total phenolic content (TPC) and total flavonoid content (TFC) were determined using Folin-Ciocalteu’s and aluminium chloride colourimetric assays, respectively. Antioxidant capacities were analysed via ferric-reducing antioxidant power (FRAP) and a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The results showed that microwave-dried S. crispus leaves exhibited minimal alterations in colour attributes L*, a*, and b*, closely resembling the fresh leaves (p &gt; 0.05). Microwave drying significantly preserved TPC (145.42 ± 1.61 mg GAE/g), TFC (117.27 ± 5.10 mg QE/g), FRAP activity (258.92 ± 0.15 µg TE/g extract), and displayed the most potent DPPH scavenging half-maximal inhibitory concentration (7.58 ± 0.48 µg/ml) compared to other methods (p &lt; 0.05). Notably, the DPPH scavenging potency surpassed that of the synthetic antioxidant butylated hydroxytoluene. In conclusion, microwave drying appeared to be an efficient method for preserving the colour and antioxidant properties of S. crispus leaves. It highlights its potential as a favourable drying technique for conserving bioactive compounds in medicinal plant materials, offering promising applications in the nutraceutical and pharmaceutical fields.

An acceptability and feasibility investigation of a community-based motor program for autistic children with moderate and high support needs

BackgroundGeneral motor impairments are ubiquitous in Autism and are positively correlated with autism symptom severity. This study assessed the feasibility and acceptability of a 13-week community-based motor program for autistic children with moderate and high support needs (MHS). MethodIn this exploratory single arm within-subject study, 10 autistic children with MHS, ages 4–10 years, completed a community-based motor program delivered in a one-on-one format by therapists. Feasibility was determined through recruitment, retention, attendance, enjoyment, engagement and useability of motor, physical activity (PA), and behavioural assessment tools. Thematic analysis evaluated post-intervention semi-structured parent interviews. ResultsHigh program attendance and retention were demonstrated, and therapists reported child engagement and enjoyment were high. Identified themes revealed parents perceived unexpected substantial positive impacts including improvements in social, motor, and behavioural outcomes. They highly valued both the program and the therapeutic relationships fostered within it. Although parents of the children with the higher support needs reported the most substantial improvements, these children were unable to score on motor assessments due to difficulties following instructions and off-task behaviours. Additionally, only four participants wore an accelerometer-based PA monitor. ConclusionsThis community-based motor program was considered feasible and acceptable by the children’s parents, and qualitative findings provided valuable insights into clinical practice for children with MHS. However, recruitment challenges and assessment tools being unfeasible for children with higher support needs led to low participant numbers. Future evaluations should explore alternative assessment measures and study designs, given the challenges associated with studying such a heterogenous and complex group.