Development of highly sensitive and accurate biosensors still faces a great challenge. Herein, glucose oxidase (GOx) is efficiently immobilized on the AuCu hydrogels owing to their porous structure ...and interfacial interaction, demonstrating enhanced catalytic activity, satisfactory stability and recyclability. Besides, by integration of AuCu@GOx and electrochromic material of Prussian blue, a sensitive and stable biosensing platform based on the excellent electrochromic property of Prussian blue and the enhanced enzyme activity of AuCu@GOx is developed, which enables the electrochemical and visual dual-mode detection of glucose. The as-constructed biosensing platform possesses a wide linear range, and good selectivity for glucose detection with a limit of detection of 0.82 μM in visual mode and 0.84 μM in electrochemical mode. This easy-to-operate biosensing platform opens a door for the practical application of the multi-mode strategy for glucose detection.
The current advancements in nanotechnology had exquisite impacts on biocatalysis. Enzymes are exceptional biocatalysts because of their excellent substrate selectivity, regio- and stereo-specificity, ...and capacity to accelerate the reaction rate up to several orders of magnitude. One of the significant challenges in biotechnology is the utilization and development of enzymes as reliable biocatalysts. Applications of enzymes have drawn a lot of attention as demand for environmentally friendly and sustainable operations increases. Enzymes are promising biocatalysts with a wide range of uses, including as a biosensor, in food, agricultural, and pharmaceutical industries. The distinctive catalytic chemistry of enzyme-linked compatible nanostructures put forward many applications, including biocatalysis. The most recent advancements in enzyme immobilization organic
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inorganic supports—including carbon-based, polymeric or hybrid, metal–organic framework—as well as various nanomaterials comprised of metals and metal oxides are discussed. The methods for immobilizing enzymes onto carriers and their stability and catalytic properties are also highlighted. The synergistic coupling of nanotechnology with biotechnology covers a broad range of tremendous applications. Nanostructures have specific characteristics that can balance parameters like effective encapsulation of enzymes, porosity, etc., which present peculiar prospects for designing an ideal biocatalyst. For synthetic chemistry and bio-manufacturing, photo-enzymes are potentially attractive biocatalysts. This review highlights that efforts are underway to bring the benefits of combining two research-intensive fields, biocatalysis and photo-biocatalysis, in a meaningful way.
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•Recent progress in enzymatic remediation of phenolic wastewaters have been reviewed.•Homogenous and heterogeneous enzymatic remediation processes have been addressed.•The impact of the key ...operational factors have been highlighted.•The key limitations and obstacles still faced by the process have been discussed.•Proposals for future research to address the unresolved challenges are included.
Water pollution is one of the serious environmental problems threatening the sustainable development of human civilization. Many phenolic compounds are hazardous, toxic, endocrine disrupting, mutagenic, teratogenic, and/or carcinogenic. They also cause severe damages to marine ecosystem. Accordingly, their removal from polluted wastewaters prior to its discharge to the environment is a mandatory task. Several processes have been proposed for treating phenol-contaminated waters. Among the proposed treatment processes is the enzymatic method. Thus, the key objective of this review article is to present the recent progress in utilizing peroxidases and laccases for the remediation of phenolic wastewaters. Both homogenous and heterogeneous enzymatic processes to remove different phenolic pollutants from wastewaters will be reviewed. Recent studies on the effects of the key operational factors (i.e., temperature and pH) will also be presented. Additionally, emerging trends in enzymatic wastewater treatment will be addressed. The obstacles and challenges facing the large scale applications of enzymatic remediation of phenolic wastewaters will be highlighted. More importantly, several ideas for addressing the limitations of the process and improving its efficiency and viability will be provided. These ideas might form the basis for future studies on developing a more effective enzymatic process for treating wastewaters contaminated with phenolic pollutants, which is a growing environmental problem worldwide.
•A novel 3-layer EMR is designed for the intermediate-sized oligodextran production.•The EMR configuration greatly affect the production performance.•Dextranase immobilized on the electrospun fibers ...had high enzyme activity.•Hydrophilic RC10 membrane is good at antifouling and thus had the best performance.
Enzymatic conversion processes face challenges in controlling oligosaccharide molecular weight (Mw). Enzymatic membrane reactors (EMRs) with immobilized enzymes address this, but direct enzyme immobilization on the membrane surface can lead to deactivation and reduced hydrolysis efficiency. This study proposes a novel EMR configuration: a three-layer structure. An electrospun porous fibrous layer, modified with PDA, TA, and APTES, serves as a mechanical support layer. A commercial separation membrane is positioned below. This configuration enhances enzyme activity and selectivity. Using a “fouling-induced” technique, immobilized activity of the enzyme (i.e. dextranase) significantly increased to 11.5 µmol-isomaltose/min, surpassing incubation-immobilized dextranase (0.075 µmol-isomaltose/min). The additional layer preserves catalytic patterns, reducing fouling and ensuring high selectivity. The EMR configuration excels in producing low Mw oligosaccharides. The catalytic layer achieves 11.3 µmol-isomaltose/min, while the membrane exhibits exceptional selectivity and stability. The hydrophilic RC10 membrane with small pores performs best. This study highlights the potential of the EMR system for efficient production of stable low Mw oligosaccharides. Insights into optimizing enzyme immobilization strategies and membrane selection benefit enzymatic conversion processes.
•A new activated hNF-lipase was synthesized.•Ca2+ not only induced self-assemble of nanoflowers, but also activated the lipase from A. oryzae.•Tween-80 acts as an excellent activator for lipase from ...A. oryzae.•The activated hNF-lipase exerted enhanced enzymatic and stability.
Lipase-inorganic hybrid nanoflowers were prepared using Ca3(PO4)2 as the inorganic component and lipase from Aspergillus oryzae (A. oryzae) as the organic component. The influences of metal ions with different valence, various additives (surfactant), and synthesis conditions on the activity of the lipase hybrid nanoflowers were systematically investigated. Results revealed that the valence state of metal ions played an important role on the shape and activity of lipase hybrid nanoflowers. The synthesized lipase hybrid nanoflowers using bivalence metal ions (Ca2+, Mn2+, and Zn2+) as the inorganic components exhibited relative high activity. However, very low activities were observed in the lipase hybrid nanoflowers using univalent metal ions (Ag+) or trivalent metal ions (Al3+, Fe3+). More importantly, Ca2+ not only induced self-assemble of lipase hybrid nanoflowers, but also activated the enzyme activity by inducing conformational changes in lipase from A. oryzae. As a result, lipase/Ca3(PO4)2 hybrid nanoflowers (hNF-lipase) exhibited the high activity. The hNF-lipase displayed 9, 12, and 61 folds higher activity than lipase/Ag3PO4 hybrid nanoflowers, lipase/AlPO4 hybrid nanoflowers, and lipase/FePO4 nanoflowers, respectively. Compared with free lipase, the hNF-lipase displayed 172 % increase in activities by using 0.15 mM Tween-80 as an activity inducer (activated hNF-lipase). Furthermore, the hNF-lipase and activated hNF-lipase exhibited increased stability against high temperature and denaturant, and had good storage stability and reusability.
Enzyme immobilization is a well-known method for the improvement of enzyme reusability and stability. To achieve very high effectiveness of the enzyme immobilization, not only does the method of ...attachment need to be optimized, but the appropriate support must be chosen. The essential necessities addressed to the support applied for enzyme immobilization can be focused on the material features as well as on the stability and resistances in certain conditions. Ceramic membranes and nanoparticles are the most widespread supports for enzyme immobilization. Hence, the immobilization of enzymes on ceramic membrane and nanoparticles are summarized and discussed. The important properties of the supports are particle size, pore structure, active surface area, volume to surface ratio, type and number of reactive available groups, as well as thermal, mechanical, and chemical stability. The modifiers and the crosslinkers are crucial to the enzyme loading amount, the chemical and physical stability, and the reusability and catalytical activity of the immobilized enzymes. Therefore, the chemical and physical methods of modification of ceramic materials are presented. The most popular and used modifiers (e.g. APTES, CPTES, VTES) as well as activating agents (GA, gelatin, EDC and/or NHS) applied to the grafting process are discussed. Moreover, functional groups of enzymes are presented and discussed since they play important roles in the enzyme immobilization via covalent bonding. The enhanced physical, chemical, and catalytical properties of immobilized enzymes are discussed revealing the positive balance between the effectiveness of the immobilization process, preservation of high enzyme activity, its good stability, and relatively low cost.
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•Properties of good ceramic support for immobilization of enzymes are described.•Challenges and factors affecting immobilization efficiency are characterized.•The immobilization procedures of enzyme on ceramic support are discussed.•The uses of immobilized enzymes in water treatment and sensing are reviewed.•Future perspectives for the immobilized enzyme membranes are presented.
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•Endo-hydrolytic activity of free dextranase is transformed to exo-hydrolytic after covalent immobilization.•Noncovalent immobilization of dextranase maintains its endo-hydrolysis ...behavior.•Matching target products generation and separation efficiency can control product molecular weight and mitigate fouling.•A desirable enzyme membrane reactor requires highly active enzyme, strong internal mass transfer and high permselective membrane.•Immobilization is not necessary in enzyme membrane reactor if enzyme has good shear resistance and acceptable stability.
Enzyme membrane reactor (EMR) provides an effective strategy for controlling molecular weight (Mw) of oligodextrans. However, the synergistic effect between dextran hydrolysis and product separation as well as continuous operation stability remains still unclear. We observed that covalently immobilized dextranase exhibited more obvious exo-hydrolysis behavior compared to free enzymes probably due to enzyme conformational alterations. Using non-covalently immobilized enzyme, suitable ultrafiltration membrane, optimal substrate/enzyme ratio and matched permeate flux, the yield of the target product reached 62.8%. However, the non-covalently immobilized dextranase exhibited reduced hydrolytic activity and more obvious membrane fouling (caused by high-Mw dextran). When free dextranase with high activity was used together with suitable permeate flux and high shear rate, the yield increased to 72.0%. The obtained EMR maintained stable for 8 h with slight fouling formation because enzymatic hydrolysis and membrane separation were well matched. The polydispersity index of the target product reached 1.3 (analytical grade) following diafiltration purification.
Biomolecules, such as nutrients in the bloodstream and lymph, are important indicators of overall health and body function. Biomolecule detection using low-cost and disposable sensor devices could ...help improve health monitoring and treatment outcomes. Point-of-care testing is expected to be a rapid and economical diagnostic tool compared with conventional laboratory-based testing. Recently, the integration of microfluidics and enzyme immobilization technology has enabled the development of low-cost, time-efficient, and high-accuracy analytical biosensors for detecting biomolecules. Herein, we reviewed recent advancements in enzyme-immobilized microfluidic devices for biomolecule measurement, and summarized techniques for the preparation of immobilized enzymes for use as biosensors and in biomolecule detection techniques. Additionally, the advantages, limitations, and future perspectives of enzyme-immobilized microfluidic devices are discussed.
•Recent advancements in enzyme-immobilized microfluidic devices for biomolecule measurement are discussed.•Techniques for the preparation of immobilized enzymes for use in biomolecule detection techniques are summarized.•Advantages, limitations, and future perspectives of enzyme-immobilized microfluidic devices are discussed.
The enzymatic processes are increasingly highlights, especially in the synthesis of chemical products with high added value. The enzyme immobilization can improve industrial biocatalytic processes. ...The immobilization of enzymes provides the production of efficient, stable biocatalysts, possibility of reuse and easy purification of the products, when compared to the free enzymes. There is a growing research for more efficient methods of enzyme immobilization. In this context, the choice of support and immobilization strategy can significantly improve the final enzymatic properties. In this review paper, we aimed to discuss the versatility of biocatalysts immobilized enzymes design, focusing on the opportunities and disadvantages for each method presented. They discussed the recent development of enzyme immobilization methods and applications relating the final properties of the produced biocatalysts with the desired goals.
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