Comparative study of catalase immobilization via adsorption on P(MMA-co-PEG500MA) structures as an effective polymer support

Biodegradation of environmental pollutants using catalase-based biocatalytic systems

The synergistic combination of biocatalysts and nanomaterials provides a new interface of a robust biocatalytic system that can effectively remediate environmental pollutants. Enzymes, such as catalase-based constructs, impart the desired candidature for catalytic transformation processes and are potential alternatives to replace conventional remediation strategies that have become laborious and somewhat inefficient. Furthermore, the controlled or uncontrolled discharge of various emerging pollutants (EPs) into water bodies is equally proportional to the fast-growing population and extensive urbanization. EPs affect the entire living being and continuously deteriorate the environmental system, directly or indirectly. The occurrence of EPs (even released after partial treatments, but still in bioactive forms) disturbs ecological integrity. Due to the ineffectiveness of in-practice traditional remediation processes, new and robust treatment measures as effective and sustainable remediation have become a meaningful goal. In this context, special attention has been shifted to engineering an enzyme (catalase)-based biodegradation system with immense prospects in environmental cleanup. The unique synergistic combination of nanomaterials (having multifunctional attributes) with enzymes of interest makes them a state-of-the-art interface that can further ameliorate bio-catalysis and biodegradation performance. This review covers current research and scientific advancement in developing and deploying catalase-based biocatalytic systems to mitigate several EPs from the environment matrices. The biocatalytic features of catalase, along with the mechanistic insight into H₂O₂ neutralization, several nano-based materials loaded with catalase, including nanoparticles (NPs), carbon nanotubes (CNTs), metal-organic frameworks (MOFs), polymeric-based composites, oxime-functionalized cryo-gel disks, electro-spun nanofibrous membranes, and other hybrid materials have also been discussed with suitable examples.

Synthesis and Characterization of a New Cryogel Matrix for Covalent Immobilization of Catalase

The advantages of cryogels for enzyme immobilization applications include their mechanical and chemical robustness, ease of production, superior porosity, and low cost. Currently, many researchers are exploring porous material-based systems for enzyme immobilization that are more efficient and economically viable. Here, poly(2-Hydroxyethyl methacrylate-co-allyl glycidyl ether) (p(HEMA-co-AGE)) cryogel matrices were synthesized via the free radical cryopolymerization method to be employed as the support material. For the immobilization of the catalase enzyme onto the p(HEMA-co-AGE) cryogel matrix (catalase@p(HEMA-co-AGE), the best possible reaction conditions were determined by altering parameters such as pH, catalase initial concentration, and flow rate. The maximum catalase immobilization amount onto the p(HEMA-co-AGE) cryogel was found to be 48 mg/g cryogel. To determine the advantages of the cryogel matrix, e.g., the stability and reusability of the cryogel matrix, the adsorption–desorption cycles for the catalase enzyme were repeated five times using the same cryogel matrix. At the end of the reusability tests, it was found that the cryogel was very stable and maintained its adsorption capacity with the recovery ratio of 93.8 ± 1.2%. Therefore, the p(HEMA-co-AGE) cryogel matrix affords repeated useability, e.g., up to five times, without decreasing its catalase binding capacities significantly and has promising potential for many industrial applications. Cryogels offer clear distinctive advantages over common materials, e.g., micro/nano particles, hydrogels, films, and composites for these applications. At present, many researchers are working on the design of more effective and economically feasible, porous material-based systems for enzyme immobilization

Modifying Thermostability and Reusability of Hyperthermophilic Mannanase by Immobilization on Glutaraldehyde Cross-Linked Chitosan Beads

In the current study, the purified β-mannanase (Man/Cel5B) from Thermotoga maritima was immobilized on glutaraldehyde cross-linked chitosan beads. The immobilization of Man/Cel5B on chitosan beads was confirmed by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. After immobilization, the protein loading efficiency and immobilization yield were found to be 73.3% and 71.8%, respectively. The optimum pH for both free and immobilized enzymes was found to be pH 5.5. However, the optimum temperature of immobilized Man/Cel5B increased by 10 °C, from 85 °C (free Man/Cel5B) to 95 °C (Immobilized). The half-life of free and immobilized enzymes was found to be 7 h and 9 h, respectively, at 85 °C owing to the higher thermostability of immobilized Man/Cel5B. The increase in thermostability was also demonstrated by an increase in the energy of deactivation (209 kJmol⁻¹) for immobilized enzyme compared to its native form (92 kJmol⁻¹), at 85 °C. Furthermore, the immobilized Man/Cel5B displayed good operational stability as it retained 54% of its original activity after 15 repeated catalytic reactions concerning its free form.

Stabilizing bienzymatic cascade catalysis via immobilization in ZIF-8/GO composites obtained by GO assisted co-growth

Enzyme catalysis has clear advantages in the process of oxidizing glucose to produce gluconic acid. In the enzyme cascade, the improvement of the cascade efficiency is desired but challenging. Graphene oxide (GO) and ZIF-8 composites as enzyme support offer the promising opportunity that not only the cascade efficiency can be improved by control the distance between two enzymes, but also the stability can be improved. Here, a new strategy of GO assisted co-growth of ZIF-8 and enzyme was carried in a one-pot synthesis. Glucose oxidase&catalase immobilized in the ZIF-8/GO composites can obtain 98% residual activity after 15 days of storage with almost no enzyme shedding. The residual activity is still higher than 75% after 5 repeated uses. The presented method of controllable growth of metal organic frameworks on 2D nanosheet can also be extended for renewable energy devices, gas storage and separation of small molecules.

A New Clark-Type Layered Double Hydroxides-Enzyme Biosensor for H2O2 Determination in Highly Diluted Real Matrices: Milk and Cosmetics

A new catalase amperometric biosensor for hydroperoxides detection has been built as part of research aimed at the development of biosensors based on layered double hydroxides (LDH) used as support for enzyme immobilization. The fabricated device differs from those developed so far, usually based on an LDH enzyme nanocomposite adsorbed on a glassy carbon (GC) electrode and cross-linked by glutaraldehyde, since it is based on an amperometric gas diffusion electrode (Clark type) instead of a GC electrode. The new biosensor, which still uses LDH synthesized by us and catalase enzyme, is robust and compact, shows a lower LOD (limit of detection) value and a linearity range shifted at lower concentrations than direct amperometric GC biosensor, but above all, it is not affected by turbidity or emulsions, or by the presence of possible soluble species, which are reduced to the cathode at the same redox potential. This made it possible to carry out accurate and efficient determination of H2O2 even in complex or cloudy real matrices, also containing very low concentrations of hydrogen peroxide, such as milk and cosmetic products, i.e., matrices that would have been impossible to analyze otherwise, using conventional biosensors based on a GC–LDH enzyme. An inaccuracy ≤ 7.7% for cosmetic samples and ≤8.0% for milk samples and a precision between 0.7 and 1.5 (as RSD%), according to cosmetic or milk samples analyzed, were achieved.

Grafted carrageenan: alginate gel beads for catalase enzyme covalent immobilization

A new matrix formulation was devised for catalase immobilization. Carrageenan-alginate beads different ratios were developed and soaked into different ratios of CaCl₂-KCl as a hardening solution. The best formulation for loading capacity was selected, treated with polyethylene imine followed by glutaraldehyde and further studied. The best concentration of catalase for immobilization was 300U/ml and the best loading time was 6 h. The catalytic properties increased after immobilization and the immobilized catalase achieved optimum activity at a temperature range of 30-50 °C that was compared to the optimum activity of free catalase which occurred at 40 °C. Higher catalytic activity of immobilized catalase occurred at alkaline pHs than the free one which achieved optimum catalytic activity at neutral pH. A comparison between the kinetic parameters of immobilized and free catalase showed variation. The K _M and Vmax of the immobilized catalase were 2.4 fold and six times higher than those of free catalase. The results of the study indicate that the formulated matrix can be used as a good matrix for catalase enzyme in various industrial applications.

Cibacron blue F3GA incorporated immobilized metal chelate affinity sorbent as a high efficient affinity immobilization materials for catalase enzyme

Catalase is a metalloenzyme commonly found in almost all plant and animal tissues and catalyzes the conversion of hydrogen peroxide to less reactive molecules. It is used for the elimination of hydrogen peroxide in biological, biomedical, food and textile applications. For this purpose, a novel affinity sorbent [poly(methacrylic acid- N-isopropyl acrylamide-CB-Fe³⁺, (p(MAA-NIPAAM)-CB-Fe³⁺)] for the determination and it was first developed using MAA and NIPAAM monomers. After characterization with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray Photoelectron Spectroscopy (XPS), adsorption parameters were determined. Reusability of p(MAA-NIPAAM)-CB-Fe³⁺ sorbent was determined after by determining the appropriate desorption agent for desorption of adsorbed catalase in the developed sorbent. It was determined that catalase adsorption could be performed with 0.01 g of sorbent in 45 min. The maximum adsorption capacity for catalase adsorption was determined as 243.17 mg/g with the use of sorbent. The operational and storage stability of the immobilized catalase was found to be high as expected. The conversion of H₂O₂ can be successfully performed by the immobilized enzyme in the prepared sorbent. It has been proven that the affinity of catalase for its substrate is increased by immobilization.