Trends in the development of innovative nanobiocatalysts and their application in biocatalytic transformations

Immobilization of recombinant serine protease from Virgobacillus natechei FarDT on amino graphene-chitosan biocompatible nanohybrid for enhancing pH and thermal stability

The serine protease gene was heterologously expressed in Escherichia coli BL21 (DE3) using the PET 28a vector. The purified enzyme was immobilized on a nanohybrid of amino graphene and chitosan. The characterization of synthesized nanohybrids and immobilized enzymes was confirmed by Fourier transform infrared (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), and field emission scanning electron microscopy (FE-SEM). Immobilization increased the temperature optimum from 60 to 70 °C for both free and immobilized enzymes, while the optimal pH of the enzymes did not change post-immobilization (pH 8). The immobilized biocatalyst significantly enhanced thermal stability, as well as enzyme stability at significant pH ranges. After 30 days of storage, the immobilized enzymes exhibited approximately 83 % of their relative activity, while the free protease retained only 56 % of its initial activity. Stabilization also altered the kinetic parameters (increasing Km, decreasing Kcat/Km, and Vmax) and thermodynamic parameters (increasing enzyme half-life and activation energy). The study's outcomes represent a significant advancement in the realm of enzyme synthesis and its stabilization using several combined technologies, including enzyme production with recombinant DNA technology based on gene synthesis, and its stabilization using a hybrid substrate synthesized from nanomaterials. Based on these findings, the immobilized recombinant enzyme has high potential for industrial use as an efficient and stable biocatalyst.

Enzyme immobilization with nanomaterials for hydrolysis of lignocellulosic biomass: Challenges and future Perspectives

Enzyme immobilization has emerged as a prodigious strategy in the enzymatic hydrolysis of lignocellulosic biomass (LCB) promising enhanced efficacy and stability of the enzymes. Further, enzyme immobilization on magnetic nanoparticles (MNPs) facilitates the easy recovery and reuse of biocatalysts. This results in the development of a nanobiocatalytic system, that serves as an eco-friendly and inexpensive LCB deconstruction approach. This review provides an overview of nanomaterials used for immobilization with special emphasis on the nanomaterial-enzyme interactions and strategies of immobilization. After the succinct outline of the immobilization procedures and supporting materials, a comprehensive assessment of the catalysis enabled by nanomaterial-immobilized biocatalysts for the conversion and degradation of lignocellulosic biomasses is provided by gathering state-of-the-art examples. The challenges and future directions associated with this technique providing a potential solution in the present article. Insight on the recent advancements in the process of nanomaterial-based immobilization for the hydrolysis of lignocellulosic biomass has also been highlighted in the article.

Green nanobiocatalysts: enhancing enzyme immobilization for industrial and biomedical applications

Nanobiocatalysts (NBCs), which merge enzymes with nanomaterials, provide a potent method for improving enzyme durability, efficiency, and recyclability. This review highlights the use of eco-friendly synthesis methods to create sustainable nanomaterials for enzyme transport. We investigate different methods of immobilization, such as adsorption, ionic and covalent bonding, entrapment, and cross-linking, examining their pros and cons. The decreased environmental impact of green-synthesized nanomaterials from plants, bacteria, and fungi is emphasized. The review exhibits the various uses of NBCs in food industry, biofuel production, and bioremediation, showing how they can enhance effectiveness and eco-friendliness. Furthermore, we explore the potential impact of NBCs in biomedicine. In general, green nanobiocatalysts are a notable progression in enzyme technology, leading to environmentally-friendly and effective biocatalytic methods that have important impacts on industrial and biomedical fields.

Biocatalytic Performance of β-Glucosidase Immobilized on 3D-Printed Single- and Multi-Channel Polylactic Acid Microreactors

Microfluidic devices have attracted much attention in the current day owing to the unique advantages they provide. However, their application for industrial use is limited due to manufacturing limitations and high cost. Moreover, the scaling-up process of the microreactor has proven to be difficult. Three-dimensional (3D) printing technology is a promising solution for the above obstacles due to its ability to fabricate complex structures quickly and at a relatively low cost. Hence, combining the advantages of the microscale with 3D printing technology could enhance the applicability of microfluidic devices in the industrial sector. In the present work, a 3D-printed single-channel immobilized enzyme microreactor with a volume capacity of 30 μL was designed and created in one step via the fused deposition modeling (FDM) printing technique, using polylactic acid (PLA) as the printing material. The microreactor underwent surface modification with chitosan, and β-glucosidase from Thermotoga maritima was covalently immobilized. The immobilized biocatalyst retained almost 100% of its initial activity after incubation at different temperatures, while it could be effectively reused for up to 10 successful reaction cycles. Moreover, a multi-channel parallel microreactor incorporating 36 channels was developed, resulting in a significant increase in enzymatic productivity.

Synthesis and analysis of silica nanocarriers for pectinase immobilization: Enhancing enzymatic stability for continuous industrial applications

Pectinolytic enzymes are among the important group of industrial enzymes that have wide applications in different food industries. In this study, pectinase-based silica nanocarriers were synthesized using co-precipitation and cross-linking techniques. The resulting silica nanoparticles were investigated using scanning electron microscopy (SEM), energy-dispersive electron microscopy (EDEX), and X-ray diffraction (XRD) for determination of its morphology, elemental composition, and crystalline pattern. Under the optimal immobilization conditions like 1.5 % glutaraldehyde, 3000 IU/mg pectinase concentration, 90 min immobilization time and 40 °C immobilization temperature, pectinase showed maximum immobilization yield. The immobilization of pectinase onto the silica nanocarriers led to enhanced catalytic characteristics, displaying higher enzymatic activity across various temperature and pH levels compared to soluble pectinase. Moreover, the immobilization substantially improved the temperature stability of pectinase, exhibiting 100 % of its initial activity even after 120 h of pre-incubation at 50 °C. Additionally, the silica nanocarrier pectinase retained 100 % of its original activity even after being reused 10 times in a single batch of reactions. These findings indicate that the immobilization of silica nanocarriers effectively enhances pectinase's industrial capabilities, making it economically feasible for industrial use and an efficient system for various biotechnological applications.

Optimization of asymmetric bioreduction conditions of 1-indanone by Leuconostoc mesenteroides N6 using a face-centered design-based multi-objective optimization model

There has been an increasing interest in biocatalysts over the past few decades in order to obtain high efficiency, high yield, and environmentally benign procedures aiming at the manufacture of pharmacologically relevant chemicals. Lactic Acid Bacteria (LAB), a microbial group, can be employed as biocatalysts while performing asymmetric reduction of prochiral ketones. In this study, Leuconostoc mesenteroides N6 was used for the asymmetric bioreduction 1-indanone. And then, a novel and innovative face-centered design-based multi-objective optimization model was used to optimize experimental conditions. Also, the experimental design factors were defined as agitation speed, incubation period, pH, and temperature for optimization to acquire the maximum enantiomeric excess (ee) and conversion rate (cr) values. When using the face-centered design-based multi-objective optimization model, the optimum culture conditions corresponded to 96.34 and 99.42%, ee and cr responses, respectively, were pH = 5.87, incubation temperature = 35 °C, incubation period = 50.88 h, and agitation speed = 152.60 rpm. Notably, the validation experiment under the optimum model conditions confirmed the model results. This study demonstrated the importance of the optimization and the efficiency of the face-centered design-based multi-objective model.

Preparation of porous chitin beads from waste crayfish shell and application in the co-immobilization of PLP and its dependent enzyme

In this study, co-immobilization of PLP and its dependent enzyme were investigated using a novel type of porous chitin bead (PCB). Crayfish shell was used to prepare PCB via dissolution of it to form beads, followed by the removal of CaCO3 and protein in-situ. Scanning electron microscopy, Fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller method showed that the PCB had abundant porous structures with deacetylation degree of 33 % and the specific surface area of 35.87 m2/g. Then, the beads are used to co-immobilize pyridoxal 5-phosphate (PLP) and l-lysine decarboxylase fused with chitin-binding protein (SpLDC-ChBD). Laser scanning confocal microscopy revealed that the beads could co-immobilize PLP and SpLDC-ChBD successfully. In addition, a packed bed was also constructed using the PCB containing co-immobilized SpLDC-ChBD and PLP. The substrate conversion remained at 91.09 % after 48 h with 50 g/L l-lysine, which showed good continuous catalysis ability. This study provides a novel method for co-immobilization of enzyme and PLP, as well as develops a new application of waste crustacean shells.

Cellulase-immobilized chitosan-coated magnetic nanoparticles for saccharification of lignocellulosic biomass

Devising and consolidating cost-effective and greener technologies for sustainable energy production pertain to some of the most pressing needs of the present times. Bioconversion of abundantly available lignocellulosic materials into fermentable sugars to produce biofuels involves the cost-extensive requirement of hydrolytic enzymes called cellulases. Cellulases are highly selective and eco-friendly biocatalysts responsible for deconstruction of complex polysaccharides into simple sugars. Currently, immobilization of cellulases is being carried out on magnetic nanoparticles functionalized with suitable biopolymers such as chitosan. Chitosan, a biocompatible polymer, exhibits high surface area, chemical/thermal stability, functionality, and reusability. The chitosan-functionalized magnetic nanocomposites (Ch-MNCs) present a nanobiocatalytic system that enables easy retrieval, separation, and recycling of cellulases, thereby offering a cost-effective and sustainable approach for biomass hydrolysis. These functional nanostructures show enormous potential owing to certain physicochemical and structural features that have been discussed in a comprehensive manner in this review. It provides an insight into the synthesis, immobilization, and application of cellulase immobilized Ch-MNCs for biomass hydrolysis. This review aims to bridge the gap between sustainable utilization and economic viability of employing replenishable agro-residues for cellulosic ethanol production by incorporating the recently emerging nanocomposite immobilization approach.

Novel biocatalysts based on enzymes in complexes with nano- and micromaterials

In today's world, there is a wide array of materials engineered at the nano- and microscale, with numerous applications attributed to these innovations. This review aims to provide a concise overview of how nano- and micromaterials are utilized for enzyme immobilization. Enzymes act as eco-friendly biocatalysts extensively used in various industries and medicine. However, their widespread adoption faces challenges due to factors such as enzyme instability under different conditions, resulting in reduced effectiveness, high costs, and limited reusability. To address these issues, researchers have explored immobilization techniques using nano- and microscale materials as a potential solution. Such techniques offer the promise of enhancing enzyme stability against varying temperatures, solvents, pH levels, pollutants, and impurities. Consequently, enzyme immobilization remains a subject of great interest within both the scientific community and the industrial sector. As of now, the primary goal of enzyme immobilization is not solely limited to enabling reusability and stability. It has been demonstrated as a powerful tool to enhance various enzyme properties and improve biocatalyst performance and characteristics. The integration of nano- and microscale materials into biomedical devices is seamless, given the similarity in size to most biological systems. Common materials employed in developing these nanotechnology products include synthetic polymers, carbon-based nanomaterials, magnetic micro- and nanoparticles, metal and metal oxide nanoparticles, metal-organic frameworks, nano-sized mesoporous hydrogen-bonded organic frameworks, protein-based nano-delivery systems, lipid-based nano- and micromaterials, and polysaccharide-based nanoparticles.

Structural insights, biocatalytic characteristics, and application prospects of lignin-modifying enzymes for sustainable biotechnology-A review

Lignin modifying enzymes (LMEs) have gained widespread recognition in depolymerization of lignin polymers by oxidative cleavage. LMEs are a robust class of biocatalysts that include lignin peroxidase (LiP), manganese peroxidase (MnP), versatile peroxidase (VP), laccase (LAC), and dye-decolorizing peroxidase (DyP). Members of the LMEs family act on phenolic, non-phenolic substrates and have been widely researched for valorization of lignin, oxidative cleavage of xenobiotics and phenolics. LMEs implementation in the biotechnological and industrial sectors has sparked significant attention, although its potential future applications remain underexploited. To understand the mechanism of LMEs in sustainable pollution mitigation, several studies have been undertaken to assess the feasibility of LMEs in correlating to diverse pollutants for binding and intermolecular interactions at the molecular level. However, further investigation is required to fully comprehend the underlying mechanism. In this review we presented the key structural and functional features of LMEs, including the computational aspects, as well as the advanced applications in biotechnology and industrial research. Furthermore, concluding remarks and a look ahead, the use of LMEs coupled with computational frameworks, built upon artificial intelligence (AI) and machine learning (ML), has been emphasized as a recent milestone in environmental research.

Engineering and application of polysaccharides and proteins-based nanobiocatalysts in the recovery of toxic metals, phosphorous, and ammonia from wastewater: A review

Global waste production is anticipated reach to 2.59 billion tons in 2030, thus accentuating issues of environmental pollution and health security. 37 % of waste is landfilled, 33 % is discharged or burned in open areas, and only 13.5 % is recycled, which makes waste management poorly efficient in the context of the circular economy. There is therefore a need for methods to recycle waste into valuable materials through resource recovery process. Progress in the field of recycling is strongly dependent on the development of efficient, stable, and reusable, yet inexpensive catalysts. In this case, a growing attention has been paid to development and application of nanobiocatalysts with promising features. The main purpose of this review paper is to: (i) introduce nanobiomaterials and describe their effective role in the preparation of functional nanobiocatalysts for the recourse recovery aims; (ii) provide production methods and the efficiency improvement of nanobaiocatalysts; (iii) give comprehensive description of valued resource recovery for reducing toxic chemicals from the contaminated environment; (iv) describe various technologies for the valued resource recovery; (v) state the limitation of the valued resource recovery; (vi) and finally economic importance and current scenario of nanobiocatalysts strategies applicable for the resource recovery processes.

Strategies to improve the mass transfer in the CO2 capture process using immobilized carbonic anhydrase

High carbon dioxide (CO₂) concentration in the atmosphere urgently requires eco-friendly mitigation strategies. Carbonic anhydrase (CA) is a high-quality enzyme protein, available from a wide range of sources, which has an extremely high catalytic efficiency for the hydration of CO₂ compared with other catalytic CO₂ conversion systems. While free CA is costly and weakly stable, CA immobilization can significantly improve its stability and allow enzyme recycling. However, gaseous CO₂ is significantly different from traditional liquid substrates. Additionally, due to the presence of enzyme carriers, there is limited mass transfer between CO₂ and the active center of immobilized CA. Most of the available reviews provide an overview of the improvement in catalytic activity and stability of CA by different immobilization methods and substrates. However, they do not address the limited mass transfer between CO₂ and the active center of immobilized CA. Therefore, by focusing on the mass transfer process, this review presents CA immobilization strategies that are more efficient and of greater environmental tolerance by categorizing the methods of enhancing the mass transfer process at each stage of the enzymatic CO₂ capture reaction. Such improvements in this green and environmentally friendly biological carbon capture process can increase its efficiency for industrial applications.

Tyrosinase Magnetic Cross-Linked Enzyme Aggregates: Biocatalytic Study in Deep Eutectic Solvent Aqueous Solutions

In the field of biocatalysis, the implementation of sustainable processes such as enzyme immobilization or employment of environmentally friendly solvents, like Deep Eutectic Solvents (DESs) are of paramount importance. In this work, tyrosinase was extracted from fresh mushrooms and used in a carrier-free immobilization towards the preparation of both non-magnetic and magnetic cross-linked enzyme aggregates (CLEAs). The prepared biocatalyst was characterized and the biocatalytic and structural traits of free tyrosinase and tyrosinase magnetic CLEAs (mCLEAs) were evaluated in numerous DES aqueous solutions. The results showed that the nature and the concentration of the DESs used as co-solvents significantly affected the catalytic activity and stability of tyrosinase, while the immobilization enhanced the activity of the enzyme in comparison with the non-immobilized enzyme up to 3.6-fold. The biocatalyst retained the 100% of its initial activity after storage at -20 °C for 1 year and the 90% of its activity after 5 repeated cycles. Tyrosinase mCLEAs were further applied in the homogeneous modification of chitosan with caffeic acid in the presence of DES. The biocatalyst demonstrated great ability in the functionalization of chitosan with caffeic acid in the presence of 10% v/v DES [Bet:Gly (1:3)], enhancing the antioxidant activity of the films.

Efficient decolorization and detoxification of triarylmethane and azo dyes by porous-cross-linked enzyme aggregates of Pleurotus ostreatus laccase

In this preset study, porous-cross-linked enzyme aggregates (CLEAs) of Pleurotus ostreatus laccase were utilized for the spontaneous decolorization and detoxification of triarylmethane and azo dyes, reactive blue 2 (RB) and malachite green (MG). The specific surface area and pore radius of the porous-CLEAs are 136.3 m2/g and 19.47 Ao, and the higher specific surface indicated greater biocatalytic efficiency, as increased mass transfer and dye interaction with the CLEAs laccase. CLEAs laccase decolorized 500 ppm of MG and RB with 98.12-58.33% efficiency after 120 min, at pH 5.0 and 50°C, without a mediator. Furthermore, the biotransformation of the MG and RB with immobilized laccase was confirmed with the help of UV-visible spectroscopy, high-performance liquid chromatography, and Fourier transform infrared spectroscopy. The reusability potential of CLEAs was assessed in batch mode for 10 cycles of dye decolorization. The decolorization activities for the immobilized laccase were 89% and 12% at the 6th cycle for MG and RB, respectively. This immobilized enzyme could effectively remove dyes from aqueous solution, and demonstrated significant detoxification in experimental plants (Triticum aestivum and Phaseolus mungo) and plant growth-promoting rhizobacteria (Azospirillum brasilense, Bacillus megaterium, Rhizobium leguminosarum, Bacillus subtilis, and Pseudomonas fluorescens). In conclusion, porous CLEAs laccase could be useful as a potential bioremediation tool for the detoxification and decolorization of dyeing wastewater in future.

Development of Pectinase Based Nanocatalyst by Immobilization of Pectinase on Magnetic Iron Oxide Nanoparticles Using Glutaraldehyde as Crosslinking Agent

To increase its operational stability and ongoing reusability, B. subtilis pectinase was immobilized on iron oxide nanocarrier. Through co-precipitation, magnetic iron oxide nanoparticles were synthesized. Scanning electron microscopy (SEM) and energy dispersive electron microscopy (EDEX) were used to analyze the nanoparticles. Pectinase was immobilized using glutaraldehyde as a crosslinking agent on iron oxide nanocarrier. In comparison to free pectinase, immobilized pectinase demonstrated higher enzymatic activity at a variety of temperatures and pH levels. Immobilization also boosted pectinase's catalytic stability. After 120 h of pre-incubation at 50 °C, immobilized pectinase maintained more than 90% of its initial activity due to the iron oxide nanocarrier, which improved the thermal stability of pectinase at various temperatures. Following 15 repetitions of enzymatic reactions, immobilized pectinase still exhibited 90% of its initial activity. According to the results, pectinase's catalytic capabilities were enhanced by its immobilization on iron oxide nanocarrier, making it economically suitable for industrial use.

Nanomaterial Constructs for Catalytic Applications in Biomedicine: Nanobiocatalysts and Nanozymes

Nanomaterials possess superior advantages due to their special geometries, higher surface area, and unique mechanical, optical, and physicochemical properties. Their characteristics make them great contributors to the development of many technological and industrial sectors. Therefore, novel nanomaterials have an increasing interest in many research areas including biomedicine such as chronic inflammations, disease detection, drug delivery, and infections treatment. Their relevant role is, in many cases, associated with an effective catalytic application, either as a pure catalyst (acting as a nanozyme) or as a support for catalytically active materials (forming nanobiocatalysts). In this review, we analyze the construction of nanozymes and nanobiocatalyst by different existing forms of nanomaterials including carbon-based nanomaterials, metal-based nanomaterials, and polymer-based nanocomposites. Then, we examine successful examples of such nanomaterials employed in biomedical research. The role played by nanomaterials in catalytic applications is analyzed to identify possible research directions toward the development of the field and the achievement of real practicability.

Graphical Abstract

Development of a Multi-Enzymatic Biocatalytic System through Immobilization on High Quality Few-Layer bio-Graphene

In this work, we report the green production of few-layer bio-Graphene (bG) through liquid exfoliation of graphite in the presence of bovine serum albumin. Microscopic characterization evaluated the quality of the produced nanomaterial, showing the presence of 3-4-layer graphene. Moreover, spectroscopic techniques also confirmed the quality of the resulted bG, as well as the presence of bovine serum albumin on the graphene sheets. Next, for the first time, bG was used as support for the simultaneous covalent co-immobilization of three enzymes, namely β-glucosidase, glucose oxidase, and horseradish peroxidase. The three enzymes were efficiently co-immobilized on bG, demonstrating high immobilization yields and activity recoveries (up to 98.5 and 90%, respectively). Co-immobilization on bG led to an increase of apparent K_M values and a decrease of apparent V_max values, while the stability of the nanobiocatalysts prevailed compared to the free forms of the enzymes. Co-immobilized enzymes exhibited high reusability, preserving a significant part of their activity (up to 72%) after four successive catalytic cycles at 30 °C. Finally, the tri-enzymatic nanobiocatalytic system was applied in three-step cascade reactions, involving, as the first step, the hydrolysis of p-Nitrophenyl-β-D-Glucopyranoside and cellobiose.

Development of 3D Printed Enzymatic Microreactors for Lipase-Catalyzed Reactions in Deep Eutectic Solvent-Based Media

In this study, 3D printing technology was exploited for the development of immobilized enzyme microreactors that could be used for biocatalytic processes in Deep Eutectic Solvent (DES)-based media. 3D-printed polylactic acid (PLA) microwell plates or tubular microfluidic reactors were modified with polyethylenimine (PEI) and lipase from Candida antarctica (CALB) was covalently immobilized in the interior of each structure. DESs were found to have a negligible effect on the activity and stability of CALB, and the system proved highly stable and reusable in the presence of DESs for the hydrolysis of p-nitrophenyl butyrate (p-NPB). A kinetic study under flow conditions revealed an enhancement of substrate accessibility in the presence of Betaine: Glycerol (Bet:Gly) DES, while the system was not severely affected by diffusion limitations. Incubation of microreactors in 100% Bet:Gly preserved the enzyme activity by 53% for 30 days of storage at 60 °C, while the buffer-stored sample had already been deactivated. The microfluidic enzyme reactor was efficiently used for the trans-esterification of ethyl ferulate (EF) with glycerol towards the production of glyceryl ferulate (GF), known for its antioxidant potential. The biocatalytic process under continuous flow conditions exhibited 23 times higher productivity than the batch reaction system. This study featured an effective and robust biocatalytic system with immobilized lipase that can be used both in hydrolytic and synthetic applications, while further optimization is expected to upgrade the microreactor system performance.

Biocatalysis: A smart and green tool for the preparation of chiral drugs

Over the last decades, biocatalysis has achieved growing interest thanks to its potential to enable high efficiency, high yield, and eco-friendly processes aimed at the production of pharmacologically relevant compounds. Particularly, biocatalysis proved an effective and potent tool in the preparation of chiral molecules, and the recent innovations of biotechnologies and nanotechnologies open up a new era of further developments in this field. Different strategies are now available for the synthesis of chiral drugs and their intermediates. Enzymes are green tools that offer several advantages, associated both to catalysis and environmentally friendly reactants. Specifically, the use of enzymes isolated from biological sources or of whole-cell represents a valuable approach to obtain pharmaceutical products. The sustainability, the higher efficiency, and cost-effectiveness of biocatalytic reactions result in improved performance and properties that can be translated from academia to industry. In this review, we focus on biocatalytic approaches for synthesizing chiral drugs or their intermediates. Aiming to unveil the potentialities of biocatalysis systems, we discuss different examples of innovative biocatalytic approaches and their applications in the pharmaceutical industry.

Immobilization of enzymes for bioremediation: A future remedial and mitigating strategy

Over the years, extensive urbanization and industrialization have led to xenobiotics contamination of the environment and also posed a severe threat to human health. Although there are multiple physical and chemical techniques for xenobiotic pollutants management, bioremediation seems to be a promising technology from the environmental perspective. It is an eco-friendly and low-cost method involving the application of microbes, plants, or their enzymes to degrade xenobiotics into less toxic or non-toxic forms. Moreover, bioremediation involving enzymes has gained an advantage over microorganisms or phytoremediation due to better activity for pollutant degradation with less waste generation. However, the significant disadvantages associated with the application of enzymes are low stability (storage, pH, and temperature) as well as the low possibility of reuse as it is hard to separate from reaction media. The immobilization of enzymes without affecting their activity provides a possible solution to the problems and allows reusability by easing the process of separation with improved stability to various environmental factors. The present communication provides an overview of the importance of enzyme immobilization in bioremediation, carrier selection, and immobilization methods, as well as the pros and cons of immobilization and its prospects.

Development of a Multi-Enzymatic Approach for the Modification of Biopolymers with Ferulic Acid

A series of polymers, including chitosan (CS), carboxymethylcellulose (CMC) and a chitosan-gelatin (CS-GEL) hybrid polymer, were functionalized with ferulic acid (FA) derived from the enzymatic treatment of arabinoxylan through the synergistic action of two enzymes, namely, xylanase and feruloyl esterase. Subsequently, the ferulic acid served as the substrate for laccase from Agaricus bisporus (AbL) in order to enzymatically functionalize the above-mentioned polymers. The successful grafting of the oxidized ferulic acid products onto the different polymers was confirmed through ultraviolet-visible (UV-Vis) spectroscopy, attenuated total reflectance (ATR) spectroscopy, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) spectroscopy. Additionally, an enhancement of the antioxidant properties of the functionalized polymers was observed according to the DDPH and ABTS protocols. Finally, the modified polymers exhibited strong antimicrobial activity against bacterial populations of Escherichia coli BL21DE3 strain, suggesting their potential application in pharmaceutical, cosmeceutical and food industries.

Synergetic integration of catalase and Fe3O4 magnetic nanoparticles with metal organic framework for colorimetric detection of phenol

Toxic phenol pollutants pose a great threat to the environment, it is urgent to develop an efficient and recyclable method to monitor phenol. Herein, we reported the synthesis of catalase-Fe₃O₄@ZIF-8 (CAT-Fe₃O₄@ZIF-8) through a novel amino-acid-boosted one-pot embedding strategy that synergically integrated catalase and magnetic Fe₃O₄ nanoparticles with ZIF-8. As expected, CAT-Fe₃O₄@ZIF-8 exhibited enhanced catalytic activity compared with Fe₃O₄@ZIF-8, CAT@ZIF-8 and catalase. Depending on the satisfactory performance of CAT-Fe₃O₄@ZIF-8, a colorimetric detection platform for phenol based on CAT-Fe₃O₄@ZIF-8 was constructed. The corresponding detection limit was as low as 0.7 μM, and a wide linear range of 5-100 μM was obtained. Besides, CAT-Fe₃O₄@ZIF-8-based colorimetric detection platform has been verified to possess high stability and recyclability. The proposed method was proven to have potential practical applications in the field of water treatment, which would advance efficient, recyclable monitoring of water quality.

Enzyme Immobilization and Co-Immobilization: Main Framework, Advances and Some Applications

Enzymes are outstanding (bio)catalysts, not solely on account of their ability to increase reaction rates by up to several orders of magnitude but also for the high degree of substrate specificity, regiospecificity and stereospecificity. The use and development of enzymes as robust biocatalysts is one of the main challenges in biotechnology. However, despite the high specificities and turnover of enzymes, there are also drawbacks. At the industrial level, these drawbacks are typically overcome by resorting to immobilized enzymes to enhance stability. Immobilization of biocatalysts allows their reuse, increases stability, facilitates process control, eases product recovery, and enhances product yield and quality. This is especially important for expensive enzymes, for those obtained in low fermentation yield and with relatively low activity. This review provides an integrated perspective on (multi)enzyme immobilization that abridges a critical evaluation of immobilization methods and carriers, biocatalyst metrics, impact of key carrier features on biocatalyst performance, trends towards miniaturization and detailed illustrative examples that are representative of biocatalytic applications promoting sustainability.

Recent Advances in the Development of Laccase-Based Biosensors via Nano-Immobilization Techniques

Monitoring phenolic compounds is critical in the environmental, food, and medical sectors. Among many recent advanced detection platforms, laccase-based biosensing platforms gave very rapid, effective, online, and in situ sensing of phenolic compounds. In laccase-based biosensors, laccase immobilization techniques have a vital role. However, a detailing of the advancements in laccase immobilization techniques employed in laccase-based biosensors is lacking in the literature. Thus, in this review, we assessed how the nano-immobilization techniques shaped the laccase biosensing platforms. We discussed novel developments in laccase immobilization techniques such as entrapment, adsorption, cross-linking, and covalent over new nanocomposites in laccase biosensors. We made a comprehensive assessment based on the current literature for future perspectives of nano-immobilized laccase biosensors. We found the important key areas toward which future laccase biosensor research seems to be heading. These include 1. A focus on the development of multi-layer laccase over electrode surface, 2. The need to utilize more covalent immobilization routes, as they change the laccase specificity toward phenolic compounds, 3. The advancement in polymeric matrices with electroconductive properties, and 4. novel entrapment techniques like biomineralization using laccase molecules. Thus, in this review, we provided a detailed account of immobilization in laccase biosensors and their feasibility in the future for the development of highly specific laccase biosensors in industrial, medicinal, food, and environmental applications.

Immobilization of Laccase on Hybrid Super-Structured Nanomaterials for the Decolorization of Phenolic Dyes

In the present work, hybrid super-structured nanomaterials were synthesized by the combination of smectite nanoclays with various carbon-based nanomaterials (graphene oxide, carbon nanotubes and adamantylamine) and were used as nanosupports for the covalent and non-covalent immobilization of laccase from Trametes versicolor (TvL). TvL was successfully immobilized on these hybrid nanomaterials, achieving high immobilization yields (up to 85%), while its conformation remained unaltered upon immobilization. The apparent kinetic constants Vmax and Km of the immobilized enzymes strongly depended on the immobilization procedure and the composition of hybrid nanomaterials. Immobilized TvL preserved up to 50% of its initial activity after 24 h of incubation at 60 °C, while free enzyme was totally deactivated. The TvL-hybrid nanomaterials bioconjugates were efficiently applied for the degradation of various synthetic dyes, exhibiting excellent decolorization capacity, as well as high reusability (up to 11 successive catalytic cycles), providing insights into the use of these bionanoconjugates on applications with environmental, and industrial interest.

Characterization of Gentisate 1,2-Dioxygenase from Pseudarthrobacter phenanthrenivorans Sphe3 and Its Stabilization by Immobilization on Nickel-Functionalized Magnetic Nanoparticles

The aim of this study was the biochemical and kinetic characterization of the gentisate 1,2-dioxygenase (GDO) from Pseudarthrobacter phenanthrenivorans Sphe3 and the development of a nanobiocatalyst by its immobilization on Ni2+-functionalized Fe3O4-polydopamine magnetic nanoparticles (Ni2+-PDA-MNPs). This is the first GDO to be immobilized. The gene encoding the GDO was cloned with an N-terminal His-tag and overexpressed in E. coli. The nanoparticles showed a high purification efficiency of GDO from crude cell lysates with a maximum activity recovery of 97%. The immobilized enzyme was characterized by Fourier transform infrared spectroscopy (FTIR). The reaction product was identified by 1H NMR. Both free and immobilized GDO exhibited Michaelis–Menten kinetics with Km values of 25.9 ± 4.4 and 82.5 ± 14.2 μM and Vmax values of 1.2 ± 0.1 and 0.03 ± 0.002 mM*s−1, respectively. The thermal stability of the immobilized GDO was enhanced at 30 °C, 40 °C, and 50 °C, compared to the free GDO. Stored at −20 °C, immobilized GDO retained more than 60% of its initial activity after 30 d, while the free enzyme completely lost its activity after 10 d. Furthermore, the immobilized nanoparticle–enzyme conjugate retained more than 50% enzyme activity up to the fifth cycle.

Thermostable Cellulases / Xylanases From Thermophilic and Hyperthermophilic Microorganisms: Current Perspective

The bioconversion of lignocellulose into monosaccharides is critical for ensuring the continual manufacturing of biofuels and value-added bioproducts. Enzymatic degradation, which has a high yield, low energy consumption, and enhanced selectivity, could be the most efficient and environmentally friendly technique for converting complex lignocellulose polymers to fermentable monosaccharides, and it is expected to make cellulases and xylanases the most demanded industrial enzymes. The widespread nature of thermophilic microorganisms allows them to proliferate on a variety of substrates and release substantial quantities of cellulases and xylanases, which makes them a great source of thermostable enzymes. The most significant breakthrough of lignocellulolytic enzymes lies in lignocellulose-deconstruction by enzymatic depolymerization of holocellulose into simple monosaccharides. However, commercially valuable thermostable cellulases and xylanases are challenging to produce in high enough quantities. Thus, the present review aims at giving an overview of the most recent thermostable cellulases and xylanases isolated from thermophilic and hyperthermophilic microbes. The emphasis is on recent advancements in manufacturing these enzymes in other mesophilic host and enhancement of catalytic activity as well as thermostability of thermophilic cellulases and xylanases, using genetic engineering as a promising and efficient technology for its economic production. Additionally, the biotechnological applications of thermostable cellulases and xylanases of thermophiles were also discussed.

Nanobiocatalysts: Advancements and applications in enzyme technology

Nanobiocatalysts are one of the most promising biomaterials produced by synergistically integrating advanced biotechnology and nanotechnology. These have a lot of potential to improve enzyme stability, function, efficiencyand engineering performance in bioprocessing. Functional nanostructures have been used to create nanobiocatalystsbecause of their specific physicochemical characteristics and supramolecular nature. This review covers a wide range of nanobiocatalysts including polymeric, metallic, silica and carbon nanocarriers as well as their recent developments in controlling enzyme activity. The enormous potential of nanobiocatalysts in bioprocessing in designing effective laboratory trials forapplications in various fields such as food, pharmaceuticals, biofuel, and bioremediation is also discussed extensively.

Multicatalytic Hybrid Materials for Biocatalytic and Chemoenzymatic Cascades—Strategies for Multicatalyst (Enzyme) Co-Immobilization

During recent decades, the use of enzymes or chemoenzymatic cascades for organic chemistry has gained much importance in fundamental and industrial research. Moreover, several enzymatic and chemoenzymatic reactions have also served in green and sustainable manufacturing processes especially in fine chemicals, pharmaceutical, and flavor/fragrance industries. Unfortunately, only a few processes have been applied at industrial scale because of the low stabilities of enzymes along with the problematic processes of their recovery and reuse. Immobilization and co-immobilization offer an ideal solution to these problems. This review gives an overview of all the pathways for enzyme immobilization and their use in integrated enzymatic and chemoenzymatic processes in cascade or in a one-pot concomitant execution. We place emphasis on the factors that must be considered to understand the process of immobilization. A better understanding of this fundamental process is an essential tool not only in the choice of the best route of immobilization but also in the understanding of their catalytic activity.