Cell‐free enzymatic catalysis (CFEC) is an emerging biotechnology that enable the biological transformations in complex natural networks to be imitated. This biomimetic approach allows industrial ...products such as biofuels and biochemical to be manufactured in a green manner. Nevertheless, the main challenge in CFEC is the poor stability, which restricts the effectiveness and lifetime of enzymes in sophisticated applications. Immobilization of the enzymes within solid carriers is considered an efficient strategy for addressing these obstacles. Specifically, putting an “armor‐like” porous metal–organic framework (MOF) exoskeleton tightly around the enzymes not only shields the enzymes against external stimulus, but also allows the selective transport of guests through the accessible porous network. Herein we present the concept of this biotechnology of MOF‐entrapped enzymes and its cutting‐edge applications.
Armorous advances: Embedding enzymes within metal–organic framework (MOF) exoskeletons improves the stability and life‐time of enzymes. This Minireview shows the progress made with MOFs‐embedded enzymes. It focuses on new embedding strategies for constructing enzyme@MOF biocomposites and the factors that influence the change in enzymatic activity. In addition, applications of enzyme@MOFs in fields such as biocatalysis, sensing, and nanocatalysis therapeutics, are presented.
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•Understanding of the enzyme immobilization is required to optimize the processes.•Immobilization parameters and courses become critical to understand the process.•Changes in enzyme ...properties during immobilization can complicate the calculations.•Likely artifacts and problems to make these calculations are discussed.•Some advices to improve the understanding of immobilization processes are given.
Biocatalytic processes continue to find increasing application in industry. Therefore enzyme immobilization has also become of increasing importance as a means of allowing enzyme containment within reactors operating in continuous mode or else separation of enzyme after use in (fed-)batch reactors, as well as potential recycle. Whilst much has been reported in the scientific literature about enzyme immobilization methods, in many cases the protocol leads to losses in enzyme activity. In this review we outline the reasons for loss of activity during immobilization and highlight suitable diagnostic tests to elucidate the precise cause and thereby methods to restore activity. The need for standardized reporting of immobilization methods is also emphasized as a means of benchmarking alternative approaches.
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•Electrospun Fe(III)-PU/AOPAN/β-CD blend nanofiber membrane was prepared.•The membrane was studied as innovative carrier/support for immobilization of laccase.•The membrane’s ...immobilization amount of laccase reached a high value of 186.34mg/g.•The immobilized laccase showed high catalytic activity and temperature/pH resistance.•Thermal/storage stability and reusability of the immobilized laccase were improved.
The aim of this study is to develop high-performance carrier/support for immobilization of enzyme (e.g., laccase). The hypothesis is that electrospun blend nanofiber membrane consisting of polyurethane (PU), amidoxime polyarcylonitrile (AOPAN), and β-cyclodextrin (β-CD) would possess the desired morphological, mechanical, and chemical properties for the coordination/chelation of Fe(III) ions and the subsequent immobilization of laccase molecules. To test this hypothesis, the Fe(III)-PU/AOPAN/β-CD nanofiber membrane has been prepared and characterized first; thereafter, the membrane’s performance as laccase immobilization carrier/support has been investigated. The results indicate that the prepared nanofiber membrane can efficiently immobilize laccase, and it also possesses excellent morphological/mechanical properties and regeneration capability. In specific, the membrane’s immobilization amount of laccase reaches a high value of 186.34mg/g; moreover, the immobilized laccase exhibits reasonably high catalytic activity and significantly improved resistance against the variations of temperature and pH value than the free laccase. Additionally, thermal stability, storage stability, and reusability of the immobilized laccase are substantially improved; and the membrane carrier/support can also be regenerated/reused for several times. Therefore, the developed electrospun PU/AOPAN/β-CD blend nanofiber membrane is a high-performance carrier/support for efficient and reusable immobilization of laccase.
In recent years, lignocellulosic wastes have gathered much attention due to increasing economic, social, environmental apprehensions, global climate change and depleted fossil fuel reserves. The ...unsuitable management of lignocellulosic materials and related organic wastes poses serious environmental burden and causes pollution. On the other hand, lignocellulosic wastes hold significant economic potential and can be employed as promising catalytic supports because of impressing traits such as surface area, porous structure, and occurrence of many chemical moieties (i.e., carboxyl, amino, thiol, hydroxyl, and phosphate groups). In the current literature, scarce information is available on this important and highly valuable aspect of lignocellulosic wastes as smart carriers for immobilization. Thus, to fulfill this literature gap, herein, an effort has been made to signify the value generation aspects of lignocellulosic wastes. Literature assessment spotlighted that all these waste materials display high potential for immobilizing enzyme because of their low cost, bio-renewable, and sustainable nature. Enzyme immobilization has gained recognition as a highly useful technology to improve enzyme properties such as catalytic stability, performance, and repeatability. The application of carrier-supported biocatalysts has been a theme of considerable research, for the past three decades, in the bio-catalysis field. Nonetheless, the type of support matrix plays a key role in the immobilization process due to its influential impact on the physicochemical characteristics of the as-synthesized biocatalytic system. In the past, an array of various organic, inorganic, and composite materials has been used as carriers to formulate efficient and stable biocatalysts. This review is envisioned to provide recent progress and development on the use of different agricultural wastes (such as coconut fiber, sugarcane bagasse, corn and rice wastes, and Brewers' spent grain) as support materials for enzyme immobilization. In summary, the effective utilization of lignocellulosic wastes to develop multi-functional biocatalysts is not only economical but also reduce environmental problems of unsuitable management of organic wastes and drive up the application of biocatalytic technology in the industry.
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•Increasing socio-economic, and environmental apprehensions stresses on valorizing lignocellulosic wastes.•Various lignocellulosic wastes as promising immobilization supports are discussed.•Research gaps – beyond our notice are discussed from the future considerations' viewpoint.
•Enzymatic endowments of immobilized carbonic anhydrase.•Current approaches and supports of carbonic anhydrase immobilization.•Studies of CO2 capture technologies ameliorated by immobilized carbonic ...anhydrase.•Advantages, issues, and limitations of enzymatic CO2 capture processes.•Industrial implementation of enzymatic CO2 capture.
Currently, amine-based solutions are considered as benchmark absorbents for CO2 capture. However, there are severe environmental concerns as well as high energy consumption. A viable option is CO2 capture utilising water as absorbent, via a biomimetic approach by the enzyme carbonic anhydrase (CA), with high selectivity, upmost performance, and environmental friendliness. However, the employment of the free form of CA in industrial applications is not rational due to the considerable amounts of enzyme required, instability and non-reusability. The immobilization of CA has attained significant interest, appearing as a promising approach to solve the problems associated with free CA. In this context, different immobilization strategies and supports have been developed to ameliorate the activity, stability, and reusability of CA enzyme, lowering the cost and increasing the process efficiency in large-scale applications. CO2 capture has been studied using immobilized CA in various technologies such as absorption columns, selective membranes, and membrane contactors. In this state-of-the-art review, the scientific literature regarding the immobilization of CA and carbon capture technologies using immobilized CA are analyzed, highlighting the benefits, issues, and limitations of processes. Moreover, modelling approaches describing the absorption of CO2 in packed-bed and membrane bioreactors with immobilized CA are presented, as well as the impact of operating parameters on bioreactors performance. The techno-economic analyses carried out on enzymatic capture processes are reviewed as well, to assess their feasibility in an industrial context. Finally, concluding remarks are made with a recommended perspective on open challenges and research priorities.
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•Mesoporous SiO2 is synthesized by spray pyrolysis using carbon nanotubes as a template.•Mesoporous SiO2 microparticles have been successfully used to immobilize enzyme.•Mesoporous ...SiO2 provides an excellent support for enzyme in biosensor or biocatalysis.
Novel mesoporous SiO2 microparticles were synthesized by spray pyrolysis using multiwalled carbon nanotubes (MCNTs) as a template. The synthesized multicompartment structure with uniform pores of 12.0 nm was used to immobilize lipase from Thermomyces lanuginosus. The total surface area of mesoporous SiO2 microparticles prepared from silica colloidal solution was increased by 26-folds compared to that of dense SiO2 particles (494 vs 19.0 m2 g−1, respectively). Mesoporous SiO2 particles showed 236% higher protein loading for lipase, than dense SiO2 particles. The maximum velocity (Vmax) and catalytic efficiencies of immobilized lipase were 3.80 and 5.90 folds higher than that of free enzyme. Contact angle analysis revealed increased hydrophobicity of the mesoporous particles, which is advantageous for lid opening at the active center, and increased activity after immobilization. We next developed a lipase/SiO2/glassy carbon electrode (GCE) biosensors. Cyclic voltammetric results showed linear responses of the lipase/SiO2/GCE bioelectrode towards tributyrin (50–300 mg dL−1) as a surface-limited reaction in Tris-HCl buffer. After 12 repetitive uses, dense SiO2- and mesoporous SiO2-bound lipase retained 74.2 and 95.4% of its original activities, respectively. Thus, given their desirable characteristics and industrial utility, greatly porous SiO2 particles may provide an excellent support for enzyme immobilization in biosensor development or biocatalysis in organic media.
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•Novel poly(methyl methacrylate)/Fe3O4 electrospun material was obtained.•The laccase immobilization by covalent binding and encapsulation was carried out.•The biocatalysts are ...characterized by improvement stability and reusability.•Removal of tetracycline by immobilized enzyme at wide range of pH and temperature.•Oxidation, dehydrogenation and demethylation governed conversion of tetracycline.
In the presented study poly(methyl methacrylate) (PMMA) and magnetite nanoparticles were used to prepare novel PMMA/Fe3O4 electrospun nanofibers. The obtained materials were characterized, and then modified and used as supports for covalent binding and encapsulation of laccase from Trametes versicolor. High enzyme loading (63.2 mg of laccase per 1 cm2 of support) was recorded for the system after covalent binding, and the formation of stable interactions was confirmed, as leaching of the enzyme from the support did not exceed 12%. Furthermore, the obtained biocatalytic systems exhibited excellent pH, thermal and storage stability as well as reusability: after 40 days of storage and 5 successive biocatalytic cycles they retained 80% of their initial properties. Experiments on the removal of antibiotic showed that both immobilized laccases possess high ability to convert tetracycline. Under optimal process conditions (pH 5, temperature 25 °C, tetracycline solution concentration 1.0 mg L−1) the removal efficiency reached 100% and 94% for covalently bonded and encapsulated laccase. Finally, the degradation products were examined to investigate the degradation mechanism. The data showed that oxidation, dehydrogenation and demethylation are major reactions in the degradation of tetracycline using immobilized laccase. The findings demonstrate clearly that laccase immobilized by covalent binding and encapsulation using electrospun materials has the potential for application in environmental protection processes for the removal of antibiotics.
Enzymes have been incorporated into a wide variety of fields and industries as they catalyze many biochemical and chemical reactions. The immobilization of enzymes on carbon nanotubes (CNTs) for ...generating nano biocatalysts with high stability and reusability is gaining great attention among researchers. Functionalized CNTs act as excellent support for effective enzyme immobilization. Depending on the application, the enzymes can be tailored using the various surface functionalization techniques on the CNTs to extricate the desirable characteristics. Aiming at the preparation of efficient, stable, and recyclable nanobiocatalysts, this review provides an overview of the methods developed to immobilize the various enzymes. Various applications of carbon nanotube-based biocatalysts in water purification, bioremediation, biosensors, and biofuel cells have been comprehensively reviewed.
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•CNTs act as stable support material for enzyme immobilization.•Enhancement of chemical properties of CNTs through surface functionalization.•Achievement of target specificity via enzyme immobilization.•Enzyme immobilized CNTs for biomedical and environmental applications.
Immobilized enzymes have received incredible interests in industry, pharmaceuticals, chemistry and biochemistry sectors due to their various advantages such as ease of separation, multiple ...reusability, non-toxicity, biocompatibility, high activity and resistant to environmental changes. This review in between various immobilized enzymes focuses on lipase as one of the most practical enzyme and chitosan as a preferred biosupport for lipase immobilization and provides a broad range of studies of recent decade. We highlight several aspects of lipase immobilization on the surface of chitosan support containing various types of lipase and immobilization techniques from physical adsorption to covalent bonding and cross-linking with their benefits and drawbacks. The recent advances and future perspectives that can improve the present problems with lipase and chitosan such as high-price of lipase and low mechanical resistance of chitosan are also discussed. According to the literature, optimization of immobilization methods, combination of these methods with other techniques, physical and chemical modifications of chitosan, co-immobilization and protein engineering can be useful as a solution to overcome the mentioned limitations.
Biocatalytic nanofiltration (NF) membranes incorporated with enzymes show high capacity for micropollutants (MPs) removal. However, there remains significant challenges such as the lack of ...molecular-level tailoring for skin layer design and effective strategy for enzyme immobilization. In this work, layer-by-layer (LBL) assembly based biocatalytic NF membranes were fabricated for bisphenol (BPA) removal by immobilizing laccase into the skin layer during the LBL polyelectrolytes assembly with controlled crosslinking and immobilization. This strategy enables simultaneous enzyme immobilization and NF skin layer formation. Three laccase immobilization strategies (i.e., post immobilization, post crosslinking, and post crosslinking and immobilization) on skin layer were explored to prepare NF membrane for evaluating BPA removal efficiency. The post immobilization was identified as the optimal strategy, which endowed the biocatalytic NF membrane with a pure water permeability of 10.9 ± 0.4 LMH/bar and MgCl2 rejection of 97.2 ± 0.3% under 2 bar pressure, alongside competitive laccase loading (238.8 ± 3.5 μg/cm2) and laccase activity (0.6 U/cm2). The optimal biocatalytic NF membrane exhibited an improvement in BPA removal of 79.5% under an incubation mode and 92.5% under a full recycling mode. The removal efficiencies were ~240% higher than that of the unmodified LBL membrane and clearly comparable to other reported biocatalytic membranes. This performance was attributed to the synergistic effect of membrane rejection, adsorption and laccase catalysis. The optimal biocatalytic NF membrane was found to be robust after six cycles within 14 days, while maintaining a relatively high BPA removal efficiency and salt rejection. Overall, our results open up a new avenue for enzyme immobilization into the skin layer of membranes for designing high-efficient biocatalytic NF membranes for MPs removal.
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•Laccase-decorated LBL skin layer is prepared on lumen side of hollow fiber membrane.•Effects of different laccase immobilization strategies on BPA removal are explored.•Post immobilization strategy endows the membrane with a competitive NF performance.•Desired BPA removal efficiency is achieved with optimal biocatalytic membrane.•The long-term reusability and stability for BPA removal are confirmed.
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