•Nano-sized meso-HOF (nmHOF) was designed for in situ enzyme immobilization.•–COOH/–NH2 residues on enzyme triggered the formation of enzyme@nmHOF.•Enzyme@nmHOF had pore size of 2.4 nm and particle ...size from 19.9 ± 6.4 to 56.4 ± 20.1 nm.•Catalytic activity of enzyme@nmHOF was close to free enzyme.•Enzyme@nmHOF exhibited excellent chemical stabilities against external stimuli.
Hydrogen-bonded organic frameworks (HOFs) are promising carriers for enzyme immobilization. HOFs suitable for enzyme reactions containing nicotinamide cofactors and/or larger molecule substrates are to be explored. Herein, we report the first example of nano-sized mesoporous HOFs (nmHOFs) for in situ enzyme immobilization. Taking tetrakis(4-amidiniumphenyl) methane (TAM) and 1,3,6,8-tetrakis(p-benzoic acid) pyrene (H4TBAPy) as building blocks, enzymes induce the assembly of TAM and H4TBAPy into enzyme-nmHOF (named enzyme@TaTb) in aqueous solution. The larger π-conjugated H4TBAPy building block and the electrostatic/hydrogen-bonding interactions between TAM in nmHOF and –COOH/–NH2 residues in enzymes trigger the formation of TaTb with pore aperture of 2.4 nm and particle size from 19.9 ± 6.4 to 56.4 ± 20.1 nm. As a demonstration, lactate dehydrogenase (LDH) that can convert pyruvate into lactate in the presence of NADH is immobilized in TaTb nmHOF. Compared with LDH@ZIF-8 and LDH@Bio-HOF-1, LDH@TaTb affords faster diffusion of NADH and pyruvate, thus exhibiting ultrahigh activity close to the free LDH. Meanwhile, the exoskeleton of TaTb nmHOF is capable of stabilizing enzymes through spatial confinement, rendering superior stability against external negative stimuli. The TaTb nmHOF is also used for immobilizing α-amylase and horseradish peroxidase. Our study may facilitate the development of HOFs into platform carriers for enzyme immobilization.
In recent years, enzyme immobilization has been presented as a powerful tool for the improvement of enzyme properties such as stability and reusability. However, the type of support material used ...plays a crucial role in the immobilization process due to the strong effect of these materials on the properties of the produced catalytic system. A large variety of inorganic and organic as well as hybrid and composite materials may be used as stable and efficient supports for biocatalysts. This review provides a general overview of the characteristics and properties of the materials applied for enzyme immobilization. For the purposes of this literature study, support materials are divided into two main groups, called Classic and New materials. The review will be useful in selection of appropriate support materials with tailored properties for the production of highly effective biocatalytic systems for use in various processes.
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•Magnetic nanoparticles synthesis and amino-functionalization.•Preparation of magnetic cross-linked laccase aggregates from Trametes hirsuta.•Easy recycling of magnetic cross-linked ...laccase aggregates.•Disability of laccase immobilization by cross-linked enzyme aggregates method.•Successful bisphenol A removal using magnetic cross-linked laccase aggregates.
Enzymatic removal of Bisphenol A (BPA), acknowledged as an environmentally friendly approach, is a promising method to deal with hard degradable contaminants. However, the application of “enzymatic treatment” has been limited due to lower operational stability and practical difficulties associated with recovery and recycling. Enzyme immobilization is an innovative approach which circumvents these drawbacks. In this study, laccase from Trametes hirsuta was used for BPA removal. Amino-functionalized magnetic Fe3O4 nanoparticles were synthesized via the co-precipitation method followed by surface modification with (3-aminopropyl)trimethoxysilane (APTMS). The as-prepared nanoparticles were utilized for the immobilization of laccase with the magnetic cross-linked enzyme aggregates method (MCLEAs). Activity recovery of 27% was achieved, while no immobilized laccase was observed in the cross-linked enzyme aggregates method. The performance of immobilized laccase was measured by analyzing the degradation of BPA pollutant. The maximum removal efficiency of 87.3% was attained with an initial concentration of 60 ppm throughout 11 h.
Immobilized laccases are widely used as green biocatalysts for bioremediation of phenolic pollutants and wastewater treatment. Metal-organic frameworks (MOFs) show potential application for ...immobilization of laccase. Their unique adsorption properties provide a synergic effect of adsorption and biodegradation. This review focuses on bioremediation of wastewater pollutants using laccase-MOF composites, and summarizes the current knowledge and future perspective of their biodegradation and the enhancement strategies of enzyme immobilization. Mechanistic strategies of preparation of laccase-MOF composites were mainly investigated via physical adsorption, chemical binding, and de novo/co-precipitation approaches. The influence of architecture of MOFs on the efficiency of immobilization and bioremediation were discussed. Moreover, as sustainable technology, the integration of laccases and MOFs into wastewater treatment processes represents a promising approach to address the challenges posed by industrial pollution. The MOF-laccase composites can be promising and reliable alternative to conventional techniques for the treatment of wastewaters containing pharmaceuticals, dyes, and phenolic compounds. The detailed exploration of various immobilization techniques and the influence of MOF architecture on performance provides valuable insights for optimizing these composites, paving the way for future advancements in environmental biotechnology. The findings of this research have the potential to influence industrial wastewater treatment and promoting cleaner treatment processes and contributing to sustainability efforts.Immobilized laccases are widely used as green biocatalysts for bioremediation of phenolic pollutants and wastewater treatment. Metal-organic frameworks (MOFs) show potential application for immobilization of laccase. Their unique adsorption properties provide a synergic effect of adsorption and biodegradation. This review focuses on bioremediation of wastewater pollutants using laccase-MOF composites, and summarizes the current knowledge and future perspective of their biodegradation and the enhancement strategies of enzyme immobilization. Mechanistic strategies of preparation of laccase-MOF composites were mainly investigated via physical adsorption, chemical binding, and de novo/co-precipitation approaches. The influence of architecture of MOFs on the efficiency of immobilization and bioremediation were discussed. Moreover, as sustainable technology, the integration of laccases and MOFs into wastewater treatment processes represents a promising approach to address the challenges posed by industrial pollution. The MOF-laccase composites can be promising and reliable alternative to conventional techniques for the treatment of wastewaters containing pharmaceuticals, dyes, and phenolic compounds. The detailed exploration of various immobilization techniques and the influence of MOF architecture on performance provides valuable insights for optimizing these composites, paving the way for future advancements in environmental biotechnology. The findings of this research have the potential to influence industrial wastewater treatment and promoting cleaner treatment processes and contributing to sustainability efforts.
•Efficient method to immobilize biomolecules to prepare several impedimetric biosensor.•Triglyceride biosensor with low detection limit and high sensitivity.•Biosensor prepared by sol-gel method and ...dip coating designed using a sequence of films.•Silica-zirconia, gold nanoparticles and silica-lipase films deposited on FTO glass.•The enzyme stays entrapped in silica film maintaining operational stability.
A novel electrochemical sensing platform was created using the formation of a sequence of films, over a conductive fluorine-doped tin oxide glass (FTO), obtained using the sol-gel method and the dip coating technique. Firstly, thin films of silica-zirconia mixed oxides were deposited, in sequence an ionic silsesquioxane film stabilizing and controlling the size of gold nanoparticles (6.5 ± 2.4 nm) was settled, and after the lipase enzyme, obtained from Candida rugosa, was entrapped into a silica film maintaining its operational stability. The films were characterized by scanning electron microscopy (SEM) with EDX, UV–Vis spectroscopy and X-ray photoelectron spectroscopy (XPS). The thickness of each film on the FTO glass was evaluated by optical profilometry. The presence of the enzyme on the platform was confirmed by cyclic voltammetry with the ρ-nitrophenyl palmitate method. This platform was applied successfully as a biosensor for tributyrin (TB) determination by electrochemical impedance spectroscopy EIS, showing low limit of detection (LD) of 1.86 μmol L−1 and high sensitivity of 5.37 μΩ μmol−1 L. The biosensor presented a low KMapp value of 22.69 μmol L− 1 and the Vmaxapp value of 85.57 μmol L−1 min−1 suggesting that the enzyme, immobilized with this method retained activity promoting a fast enzymatic reaction with the TB.
An amino-functionalized magnetic metal organic framework (MOF), Fe3O4-NH2@MIL-101(Cr), was employed for laccase immobilization for the first time. The immobilized laccase was synthesized by the ...adsorption and covalent binding method, thus exhibited high activity recovery, large immobilization capacity and good tolerance to low pH and high temperature conditions. The excellent stability enabled the immobilized laccase to retain 89% of its initial activity after storage for 28 days. When the ambient temperature reached 85 °C, the immobilized laccase showed 49.1% residual activity even after 6 h preservation. The stability of laccase in organic solvents such as methanol was also greatly improved. Application of the immobilized laccase for 2,4-dichlorophenol removal was also investigated. The adsorption by Fe3O4-NH2@MIL-101(Cr) contributed to a quick removal in the first hour, and the removal efficiency reached 87% eventually. When the reaction was completed, the immobilized laccase could be separated from the solution by a magnet. The results introduced a novel support for laccase immobilization, and the immobilized laccase had great potential in wastewater treatment.
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•A novel amino-functionalized magnetic MOF was applied for laccase immobilization.•The immobilized laccase was synthesized by the adsorption and covalent binding.•A high laccase loading and activity recovery was obtained.•The immobilized laccase showed improved thermal and storage stability.•The removal of 2,4-dichlorophenol was efficient by the immobilized laccase.
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•A new bio-catalyst was synthesized by encapsulating lipase into the ZIF-67.•The prepared catalyst was applied in transesterification of soybean oil to biodiesel.•The heterogeneous ...bio-catalyst was highly efficient, stable and reusable.
A new heterogeneous bio-catalyst was synthesized by encapsulating lipase into the microporous zeolite imidazolate framework, ZIF-67, using a bottle-around-a-ship method. The enzyme/ZIF-67 association is higher than those resulting from post-synthetic approaches. The resulting biocomposite lipase@ZIF-67 was fully characterized by UV-vis and Fourier transform infrared (FT-IR) spectroscopies, powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), Thermal gravimetric analyses (TGA), N2 adsorption–desorption and energy dispersive X-ray (EDX). The prepared bio-catalyst was successfully applied for transesterification of soybean oil to biodiesel in a solvent-free medium. The effect of different parameters, such as pH, temperature, molar ratio of methanol to oil and mass ratio of bio-catalyst to oil, was deeply investigated. Finally, the immobilized enzyme was reused during 6 cycles transesterification reaction without a significant decrease in its initial activity. This simple and efficient association procedure seems well-adapted to produce enzymatic bio-catalyst for biodiesel production.
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•Biocatalytic membrane processes produce environmentally friendly and energy-efficient processes.•Enzyme immobilization is the simplest solution to long-term operational stability, ...activity and reuse.•Modified immobilization methods improve the performance of enzymes over common immobilization methods.•Biocatalytic membranes compared with electrocatalytic and photocatalytic membrane processes.•Biocatalytic membranes have the potential to be used in antifouling and emerging pollutant degradation applications.
Biocatalytic membranes, which are fabricated by taking advantage of the synergetic effect of membranes and enzymes, have been one of the attractive treatment methods as sustainable and environmentally friendly. In biocatalytic membrane systems, enzymes can be free or immobilized, but the number of immobilized applications increases due to the advantages of immobilization. Immobilization is one of the critical points to improve the storage and operational stability of enzymes. Additionally, immobilized enzymes have a significant benefit over free enzymes in terms of reusability. This review summarizes recent advances in the preparation of biocatalytic membranes with the different immobilization methods of enzymes in/on membranes, paying particular attention to recent approaches for anti-fouling and emerging pollutant degradation applications. Also, some future outlooks were briefly presented.
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•Bioinspired coating of support layer tunes confinement strength of membrane to enzyme.•Enzyme confinement has little increment in transfer resistance for substrate and ...products.•Enzyme confinement improves storage and operating stability of biocatalytic membrane.•Biocatalytic membrane shows a stable BPA removal for 7 reuse cycles (>75%) or 36 h operation (>80%).•Enzyme mobility is proposed to reflect confinement strength and membrane performance.
Enzymes in living cells are highly dynamic but at the same time regularly confined for achieving efficient metabolism. Inspired by this phenomenon, we have prepared a novel biocatalytic membrane with high enzyme activity and stability by tuning the confinement strength of the membrane to enzyme, which was achieved via modifying the support layer of a polymeric nanofiltration (NF) membrane and reversely filtrating enzyme. A mussel-inspired coating was used to modify the support interior of the NF membrane to enhance charge and steric effects on enzyme, thus stabilizing enzyme in the membrane with little increment in mass transfer resistance for substrate and products (only 20% permeability loss with a high enzyme loading of 1.34 mg/cm2). A suitable confinement strength of the membrane to enzyme could delay the enzyme leakage and endow enzyme with certain mobility for efficient reaction. Thus, the obtained biocatalytic membrane exhibited a negligible decline in BPA removal efficiency for 7 reuse cycles (<3.5%) or 36 h continuous operation (<1%) in flow through mode, resulting in a long-term stability adequate for micropollutant removal. For the first time, enzyme mobility was defined and calculated to quantify the confinement strength of the membrane, which could be used to optimize the microenvironment for enzyme immobilization and predict the performance of the biocatalytic membrane. This work concluded that rationally regulating the enzyme mobility in the membrane and a periodic back-flushing operation for redistribution of enzymes could achieve a long-term stable removal of micropollutant in water by a biocatalytic membrane.
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