Immobilization of horseradish peroxidase on Fe3O4 magnetic nanoparticles

Background: Iron magnetic nanoparticles have attracted much attention. They have been used in enzyme immobilization because of their properties such as product is easily separated from the medium by magnetic separation. The present work was designed to immobilize horseradish peroxidase on Fe3O4 magnetic nanopraticles without modification. Results: In the present study, horseradish peroxidase (HRP) was immobilized on non-modified Fe3O4 magnetic nanoparticles. The immobilized HRP was characterized by FT-IR spectroscopy, scanning electron microscopy, and energy dispersive X-ray. In addition, it retained 55% of its initial activity after 10 reuses. The optimal pH shifted from 7.0 for soluble HRP to 7.5 for the immobilized HRP, and the optimal temperature shifted from 40\ub0C to 50\ub0C. The immobilized HRP is more thermostable than soluble HRP. Various substrates were oxidized by the immobilized HRP with higher efficiencies than by soluble HRP. Km values of the soluble and immobilized HRP were 31 and 45 mM for guaiacol and 5.0 and 7.0 mM for H2O2, respectively. The effect of metals on soluble and immobilized HRP was studied. Moreover, the immobilized HRP was more stable against high concentrations of urea, Triton X-100, and isopropanol. Conclusions: Physical immobilization of HRP on iron magnetic nanoparticles improved the stability toward the denaturation induced by pH, heat, metal ions, urea, detergent, and water-miscible organic solvent

A biocatalytic system obtained via immobilization of urease onto magnetic metal/alginate nanocomposite: Improving reusability and enhancing stability

Alginate is a biomaterial that is considered suitable for enzyme immobilization. The biocompatibility and characteristics of the immobilized system can be improved by combining alginate with magnetite Fe3O4 nanoparticles. Therefore, the current study investigated the effect of magnetite Fe3O4 NPs on urease immobilization using different concentrations of magnetite Fe3O4 NPs. The morphological features for alginate/magnetite Fe3O4 NPs before and after immobilization were studied using an SEM, TGA, and FTIR. The reusability, half-life, enzymatic kinetics, and storage stability of the enzyme were all enhanced. The immobilization efficiency was determined to be 91% at optimal conditions. The immobilized urease was reused 20 times and a recovery of 59% of the initial activity. The soluble and immobilized urease was stored at 4 °C for 12 weeks and preserved 13% and 49% of the initial activities, respectively. The optimum pH for soluble and immobilized urease activity was estimated to be 7. The optimum temperature for soluble and immobilized urease activity was found to be 35 °C and 40 °C, respectively. The kinetics parameters showed the Vmax of 4.4 and 3.1 μmol/ml·min and the Km of 49.5 and 54.6 mM for the soluble and immobilized urease, respectively. Immobilized urease had a half-life of 11–20 min. The activation energy (Ea) of immobilized urease was determined to be 32 kJ K−1 mol−1, indicating that a small quantity of energy is required to produce the activated complex of substrate hydrolysis.</p

Encapsulation of HRP Enzyme onto a Magnetic Fe3O4 Np–PMMA Film via Casting with Sustainable Biocatalytic Activity

Horseradish peroxidase (HRP) enzyme was effectively encapsulated onto an Fe3O4 nanoparticle&ndash;polymethyl methacrylate (PMMA) film via the casting method. The HRP was immobilized on the 0.5% Fe3O4Np&ndash;PMMA film and characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. Moreover, the reusability, thermal stability, optimum pH, optimum temperature, the influence of metal ions, and the effects of detergent and organic solvent were investigated. After optimizing the immobilization conditions, the highest efficiency of the immobilized enzyme was 88.4% using 0.5% Fe3O4Np&ndash;PMMA. The reusability of the immobilized HRP activity was 78.5% of its initial activity after being repeatedly used for 10 cycles. When comparing the free and immobilized forms of the HRP enzyme, changes in the optimum temperature and optimum pH from 30 to 40 &deg;C and 7.0 to 7.5, respectively, were observed. The Km and Vmax for the immobilized HRP were estimated to be 41 mM, 0.89 U/mL for guaiacol and 5.84 mM, 0.66 U/mL for H2O2, respectively. The high stability of the immobilized HRP enzyme was obtained using metal ions, a high urea concentration, isopropanol, and Triton X-100. In conclusion, the applicability of immobilized HRP involves the removal of phenol in the presence of hydrogen peroxide, therefore, it could be a potential catalyst for the removal of wastewater aromatic pollutants

Immobilization of Catalase on Chitosan/ZnO and Chitosan/ZnO/Fe2O3 Nanocomposites: A Comparative Study

The strong catalytic performance, eco-friendly reaction systems, and selectivity of enzyme-based biocatalysts are extremely interesting. Immobilization has been shown to be a good way to improve enzyme stability and recyclability. Chitosan-incorporated metal oxides, among other support matrices, are an intriguing class of support matrices for the immobilization of various enzymes. Herein, the cross-linked chitosan/zinc oxide nanocomposite (CS/ZnO) was synthesized and further improved by adding iron oxide (Fe2O3) nanoparticles. The final cross-linked CS/ZnO/Fe2O3 nanocomposite was used as an immobilized support for catalase and is characterized by SEM, EDS, and FTIR. The nanocomposite CS/ZnO/Fe2O3 enhanced the biocompatibility and immobilized system properties. CS/ZnO/Fe2O3 achieved a higher immobilization yield (84.32%) than CS/ZnO (37%). After 10 repeated cycles, the remaining immobilized catalase activity of CS/ZnO and CS/ZnO/Fe2O3 was 14% and 45%, respectively. After 60 days of storage at 4 °C, the remaining activity of immobilized enzyme onto CS/ZnO and CS/ZnO/Fe2O3 was found to be 32% and 47% of its initial activity. The optimum temperature was noticed to be broad at 25–30 °C for the immobilized enzyme and 25 °C for the free enzyme. Compared with the free enzyme optimum pH (7.0), the optimum pH for the immobilized enzyme was 7.5. The Km and Vmax values for the free and immobilized enzyme on CS/ZnO, and the immobilized enzyme on CS/ZnO/Fe2O3, were found to be 91.28, 225.17, and 221.59 mM, and 10.45, 15.87, and 19.92 µmole ml−1, respectively. Catalase immobilization on CS/ZnO and CS/ZnO/Fe2O3 offers better stability than free catalase due to the enzyme’s half-life. The half-life of immobilized catalase on CS/ZnO/Fe2O3 was between 31.5 and 693.2 min

Evaluating Desert Actinomycetes for Enzyme and Antibacterial Production

A total of 13 Actinomycete strains were isolated from 70 soil samples collected from five locations across the Jeddah Province, while the other two locations located in Baljurashi province of Saudi Arabia. All 13 isolates were purified and subjected to enzymatic screening and antibacterial assays. The results indicated that two of these isolates (AC45 and AC69) produced both enzymes and exerted some antibacterial activity. Isolate AC45 produced more amylase and polygalacturonase (697.8 and 1498.59 units/ml, respectively) than isolate AC69; however, AC69 secreted more lipase than AC45 (6957 and 22127 unit/ml, respectively). Furthermore, both AC45 and AC69 exhibited good antibacterial activity against Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus subtilis. The two isolates were identified using their 16S rRNA sequences, and the results suggest that isolate AC45 shares 99.71% similarity with Streptomyces lavenduligriseus and isolate AC69 shares 99% similarity with Streptomyces sp

In Situ Coating of Polydopamine-AgNPs on Polyester Fabrics Producing Antibacterial and Antioxidant Properties

Nanoparticles are increasingly utilized as coating materials to improve the properties of polyester textiles. In this work, polyester textiles were successfully fabricated, with hydrazide groups serving as ligands for the entrapment of sliver ions and subsequent reduction to AgNPs. Polydopamine (PDA) was used in this work to impart antibacterial and antioxidant properties to the polyester textiles through its phenolic hydroxyl groups, which can convert silver ions into AgNPs. Moreover, glucose was used as a reducing agent to create AgNPs-loaded polyester hydrazide. ATR-FTIR, SEM, EDX, thermogravimetric analysis (TGA), and tensile strength were used to characterize the pristine polyester, the polyester hydrazide, the PDA-coated AgNP-loaded polyester hydrazide and the AgNP-loaded polyester hydrazide. A broth test was also used to investigate the textile’s antimicrobial activities against Escherichia coli and Staphylococcus aureus. Overall, the composite nanocoating with PDA-AgNPs demonstrated good tensile strength and antioxidant and antibacterial characteristics, implying the practicality of PDA-AgNPs coating polyester for biomedical textile applications

Synthesis and Characterization of Aminoamidine-Based Polyacrylonitrile Fibers for Lipase Immobilization with Effective Reusability and Storage Stability

Lipases are extensively utilized industrial biocatalysts that play an important role in various industrial and biotechnological applications. Herein, polyacrylonitrile (PAN) was treated with hexamethylene diamine (HMDA) and activated by glutaraldehyde, then utilized as a carrier support for Candida rugosa lipase. In this regard, the morphological structure of modified PAN before and after the immobilization process was evaluated using FTIR and SEM analyses. The immobilized lipase exhibited the highest activity at pH 8.0, with an immobilization yield of 81% and an activity of 91%. The optimal pH and temperature for free lipase were 7.5 and 40 &deg;C, while the immobilized lipase exhibited its optimal activity at a pH of 8.0 and a temperature of 50 &deg;C. After recycling 10 times, the immobilized lipase maintained 76% of its activity and, after 15 reuses, it preserved 61% of its activity. The lipase stability was significantly improved after immobilization, as it maintained 76% of its initial activity after 60 days of storage. The calculated Km values were 4.07 and 6.16 mM for free and immobilized lipase, and the Vmax values were 74 and 77 &mu;mol/mL/min, respectively. These results demonstrated that synthetically modified PAN is appropriate for immobilizing enzymes and has the potential for commercial applications

Synthesis and Characterization of Aminoamidine-Based Polyacrylonitrile Fibers for Lipase Immobilization with Effective Reusability and Storage Stability

Lipases are extensively utilized industrial biocatalysts that play an important role in various industrial and biotechnological applications. Herein, polyacrylonitrile (PAN) was treated with hexamethylene diamine (HMDA) and activated by glutaraldehyde, then utilized as a carrier support for Candida rugosa lipase. In this regard, the morphological structure of modified PAN before and after the immobilization process was evaluated using FTIR and SEM analyses. The immobilized lipase exhibited the highest activity at pH 8.0, with an immobilization yield of 81% and an activity of 91%. The optimal pH and temperature for free lipase were 7.5 and 40 °C, while the immobilized lipase exhibited its optimal activity at a pH of 8.0 and a temperature of 50 °C. After recycling 10 times, the immobilized lipase maintained 76% of its activity and, after 15 reuses, it preserved 61% of its activity. The lipase stability was significantly improved after immobilization, as it maintained 76% of its initial activity after 60 days of storage. The calculated Km values were 4.07 and 6.16 mM for free and immobilized lipase, and the Vmax values were 74 and 77 μmol/mL/min, respectively. These results demonstrated that synthetically modified PAN is appropriate for immobilizing enzymes and has the potential for commercial applications

Facile Immobilization of Enzyme via Co-Electrospinning: A Simple Method for Enhancing Enzyme Reusability and Monitoring an Activity-Based Organic Semiconductor

The stability, reusability, and monitoring of enzyme activity have been investigated to improve their efficiency for successful utilization in a broad range of industrial and medical applications. Herein, we present a simple method for fabricating an electrospun fiber/enzyme scaffold via co-electrospinning. The characterization of soluble and immobilized α-amylases with regard to pH, thermal stability, and reusability were studied. An organic light emitting material tris­(8-hydroxyquinoline)­aluminum was incorporated to monitor the enzyme activity for several reuses

Heavy Metal Accumulation is Associated with Molecular and Pathological Perturbations in Liver of Variola louti from the Jeddah Coast of Red Sea

Large amounts of waste water are discharged daily from the Jeddah Metropolitan Area into the Red Sea. Sewage draining into the Red Sea causes widespread chemical pollution that is toxic to aquatic ecosystems. The objective of this study was to investigate the extent of pollution and assess the presence of heavy metals in fish tissue and study their association with biological and biochemical alterations. The average concentrations of heavy metals found in hepatic tissues of Variola louti fish from the polluted area, namely Cd, Cr, Cu, Fe and Zn, were 1.74, 9.69, 47.48, 4020.01 and 229.47 µg/g liver, respectively, that were significantly higher than that of samples taken from reference area (0.24, 1.98, 20.12, 721.93, 129.21 µg/g liver, respectively). The fold change of heavy metals in fish from the polluted area with respect of that of the reference area followed the order Cd &gt; Fe &gt; Cr &gt; Cu &gt; Zn. Analysis of nuclear DNA revealed that hepatic tissues of fish samples from the polluted area showed a significant increase in apoptotic cells as detected by flow cytometry and formation DNA-ladder. In addition, hepatic sections from polluted area fishes showed more fibrotic changes and collagen deposition by hematoxylin-eosin staining and Masson’s trichrome staining, respectively, compared to samples taken from the reference area. Moreover, the electrophoretic patterns of proteins of liver of fishes caught at the polluted area showed different patterns of proteins from that of the reference with bands at 42, 130 and 140 kDa, which is in a good agreement with the molecular weight of collagen type III. In conclusion, there were significant changes in the tissues of fishes in the polluted area at the cellular and the molecular levels that may be associated with an accumulation of heavy metals. Assessment of fishes as a sensitive biomonitor for the pollution of surface waters that may affect general health of human and wild life is conceivable