Enzyme immobilization: an overview on techniques and support materials

Encapsulation of Candida antarctica lipase B in metal-organic framework under ultrasound and using it to one-pot synthesis of 1,3,4,5-tetrasubstituted pyrazoles

Encapsulating the enzyme in metal-organic frameworks (MOFs) is a convenient method to prepare MOF-enzyme biocomposite. In this study, Candida antarctica lipase B (CAL-B) was chosen to immobilize in Cu-BTC MOF under ultrasound irradiation. CAL-B was immobilized in Cu-BTC under ultrasound at 21 kHz and 11.4 W/cm2 and incubation. 98% of CAL-B was immobilized in Cu-BTC with 99 U/mg activity (threefold more active than the free CAL-B). The prepared biocomposite was characterized using FT-IR, XRD, TGA, SEM, EDX, and BET. The thermal and solvent stability of CAL-B@Cu-BTC was investigated. It was found that at a temperature of 55 ℃, CAL-B@Cu-BTC maintains its activity even after 2 h of incubation. Furthermore, in the presence of 20% and 50% concentrations of MeCN, THF, and DMF, CAL-B@Cu-BTC was found to have an activity of over 80%. A prepared biocatalyst was used to synthesize 1,3,4,5-tetrasubstituted pyrazole derivatives (50-75%) in a one-pot vessel, by adding phenyl hydrazine hydrochlorides, benzaldehydes, and dimethyl acetylenedicarboxylate.

Polydopamine-functionalized polyethersulfone membrane: A paradigm advancement in the field of α-amylase stability and immobilization

Biocatalytic membranes have great potential in various industrial sectors, with the immobilization of enzymes being a crucial stage. Immobilizing enzymes through covalent bonds is a complex and time-consuming process for large-scale applications. Polydopamine (PDA) offers a more sustainable and eco-friendly alternative for enzyme immobilization. Therefore, surface modification with polydopamine as mussel-inspired antifouling coatings has increased resistance to fouling. In this study, α-amylase enzyme was covalently bound to a bioactive PDA-coated polyethersulfone (PES) membrane surface using cyanuric chloride as a linker. The optimal activity of α-amylase enzyme immobilized on PES/PDA membrane was obtained at temperature and pH of 55°C and 6.5, respectively. The immobilized enzyme can be reused up to five reaction cycles with 55 % retention of initial activity. Besides, it maintained 60 % of its activity after being stored for five weeks at 4°C. Additionally, the immobilized enzyme demonstrated increased Michaelis constant and maximum velocity values during starch hydrolysis. The results of the biofouling experiment of various membranes in a dead-end cell demonstrated that the PES membrane's water flux increased from 6722.7 Lmh to 7560.2 Lmh after PDA modification. Although α-amylase immobilization reduced the flux to 7458.5 Lmh due to enhanced hydrophilicity, compared to unmodified membrane. The findings of this study demonstrated that the membrane produced through co-deposition exhibited superior hydrophilicity, enhanced coating stability, and strong antifouling properties, positioning it as a promising candidate for industrial applications.

In-situ stabilized lipase in calcium carbonate microparticles for activation in solvent-free transesterification for biodiesel production

Biodiesel serves as a crucial biofuel alternative to petroleum-based diesel fuels, achieved through enzymatic transesterification of oil substrates. This study aims to investigate stabilized lipase (LP) within calcium carbonate (CaCO3) microparticles as a catalyst for solvent-free transesterification in biodiesel synthesis. The specific hydrolysis activity of the in-situ immobilized LP was 66% of that of free LP. However, the specific transesterification activity of immobilized LP in the solvent-free phase for biodiesel production was 2.29 times higher than that of free LP. These results suggest that the interfacial activation of LP molecules is facilitated by the inorganic CaCO3 environment. The immobilized LP demonstrated higher biodiesel production levels with superior stability compared to free LP, particularly regarding methanol molar ratio and temperature. To the best of our knowledge, there are no previous reports on the in-situ immobilization of LP in a CaCO3 carrier without any crosslinker as an interfacial-activated biocatalyst for biodiesel production.

Enhancing Performances of Enzyme/Metal-Organic Polyhedra Composites by Mixed-Protein Co-Immobilization

Protein immobilization using water-soluble ionic metal-organic polyhedra (MOPs) acting as porous spacers has recently been demonstrated as a potent strategy for the preparation of biocatalysts. In this article, we describe a mixed-protein approach to achieve biocomposites with adjustable enzyme contents and excellent immobilization efficiencies, in a systematic and well-controlled manner. Self-assembly of either cationic or anionic MOPs with bovine serum albumin or egg white lysozyme combined with enzymes (alkaline phosphatase, laccase or cytochrome c) led to solid-state catalysts with a high retention of enzyme activity. Furthermore, for all these systems, the dilution of enzymes within the solid-state composite led to noticeably improved catalytic performances, with both higher specific activity and affinity for substrate.

Immobilization of HRP enzyme on polymeric microspheres and its use in decolourisation of organic dyes

In this study, horseradish peroxidase (HRP) enzyme was immobilized on Pd(II) containing polymeric microspheres by adsorption method and used for the decolourisation of Methyl Orange (MO) and Rhodamine B (RB) dyes. The synthesized microspheres were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy-Energy Dispersive X-ray (SEM/EDX), Thermal Gravimetric Analysis (TGA). The effects of pH, dye concentration, temperature, and H2O2 concentration on the decolourisation of MO and RB were determined. According to the results of various parameters studied, when 2-AEPS-napht-HRP support was used, MO and RB were biodegraded to 69.72% and 80.65%, respectively, within 60 min. When 2-AEPS-napht-Pd-HRP support was used, MO and RB were biodegraded to 58.35% and 90.81%, respectively, under optimum conditions. When the reproducibility results of the immobilized supports were examined, it was observed that they remained efficient during the first five reusability cycles and even reached 65% decolourisation efficiency after the 9th reuse. The immobilized enzyme (2AEPS-npht-HRP and 2AEPS-npht-Pd-HRP) showed remarkable resistance to higher temperatures compared to the free enzyme.

Disposable electrochemical biosensors for the detection of bacteria in the light of antimicrobial resistance

Persistent and inappropriate use of antibiotics is causing rife antimicrobial resistance (AMR) worldwide. Common bacterial infections are thus becoming increasingly difficult to treat without the use of last resort antibiotics. This has necessitated a situation where it is imperative to confirm the infection to be bacterial, before treating it with antimicrobial speculatively. Conventional methods of bacteria detection are either culture based which take anywhere between 24 and 96 hor require sophisticated molecular analysis equipment with libraries and trained operators. These are difficult propositions for resource limited community healthcare setups of developing or less developed countries. Customized, inexpensive, point-of-care (PoC) biosensors are thus being researched and developed for rapid detection of bacterial pathogens. The development and optimization of disposable sensor substrates is the first and crucial step in development of such PoC systems. The substrates should facilitate easy charge transfer, a high surface to volume ratio, be tailorable by the various bio-conjugation chemistries, preserve the integrity of the biorecognition element, yet be inexpensive. Such sensor substrates thus need to be thoroughly investigated. Further, if such systems were made disposable, they would attain immunity to biofouling. This article discusses a few potential disposable electrochemical sensor substrates deployed for detection of bacteria for environmental and healthcare applications. The technologies have significant potential in helping reduce bacterial infections and checking AMR. This could help save lives of people succumbing to bacterial infections, as well as improve the overall quality of lives of people in low- and middle-income countries.

Efficient and easible biocatalysts: Strategies for enzyme improvement. A review

Owing to the environmental friendliness and vast advantages that enzymes offer in the biotechnology and industry fields, biocatalysts are a prolific investigation field. However, the low catalytic activity, stability, and specific selectivity of the enzyme limit the range of the reaction enzymes involved in. A comprehensive understanding of the protein structure and dynamics in terms of molecular details enables us to tackle these limitations effectively and enhance the catalytic activity by enzyme engineering or modifying the supports and solvents. Along with different strategies including computational, enzyme engineering based on DNA recombination, enzyme immobilization, additives, chemical modification, and physicochemical modification approaches can be promising for the wide spread of industrial enzyme usage. This is attributed to the successful application of biocatalysts in industrial and synthetic processes requires a system that exhibits stability, activity, and reusability in a continuous flow process, thereby reducing the production cost. The main goal of this review is to display relevant approaches for improving enzyme characteristics to overcome their industrial application.

Catalase immobilization: Current knowledge, key insights, applications, and future prospects - A review

Catalase (CAT), a ubiquitous enzyme in all oxygen-exposed organisms, effectively decomposes hydrogen peroxide (H2O2), a harmful by-product, into water and oxygen, mitigating oxidative stress and cellular damage, safeguarding cellular organelles and tissues. Therefore, CAT plays a crucial role in maintaining cellular homeostasis and function. Owing to its pivotal role, CAT has garnered considerable interest. However, many challenges arise when used, especially in multiple practical processes. "Immobilization", a widely-used technique, can help improve enzyme properties. CAT immobilization offers numerous advantages, including enhanced stability, reusability, and facilitated downstream processing. This review presents a comprehensive overview of CAT immobilization. It starts with discussing various immobilization mechanisms, support materials, advantages, drawbacks, and factors influencing the performance of immobilized CAT. Moreover, the review explores the application of the immobilized CAT in various industries and its prospects, highlighting its essential role in diverse fields and stimulating further research and investigation. Furthermore, the review highlights some of the world's leading companies in the field of the CAT industry and their substantial potential for economic contribution. This review aims to serve as a discerning, source of information for researchers seeking a comprehensive cutting-edge overview of this rapidly evolving field and have been overwhelmed by the size of publications.

Towards cost-effective drug discovery: Reusable immobilized enzymes for neurological disease research

Enzyme handling and utilization bears many challenges such as their limited stability, intolerance of organic solvents, high cost, or inability to reuse. Most of these limitations can be overcome by enzyme immobilization on the surface of solid support. In this work, the recombinant form of human cholinesterases and monoamine oxidases as important drug targets for neurological diseases were immobilized on the surface of magnetic non-porous microparticles by a non-covalent bond utilizing the interaction between a His-tag terminus on the recombinant enzymes and cobalt (Co2+) ions immobilized on the magnetic microparticles. This type of binding led to targeted enzyme orientation, which completely preserved the catalytic activity and allowed high reproducibility of immobilization. In comparison with free enzymes, the immobilized enzymes showed exceptional stability in time and the possibility of repeated use. Relevant Km, Vmax, and IC50 values using known inhibitors were obtained using particular immobilized enzymes. Such immobilized enzymes on magnetic particles could serve as an excellent tool for a sustainable approach in the early stage of drug discovery.

Engineered Proteins and Materials Utilizing Residue-Specific Noncanonical Amino Acid Incorporation

The incorporation of noncanonical amino acids into proteins and protein-based materials has significantly expanded the repertoire of available protein structures and chemistries. Through residue-specific incorporation, protein properties can be globally modified, resulting in the creation of novel proteins and materials with diverse and tailored characteristics. In this review, we highlight recent advancements in residue-specific incorporation techniques as well as the applications of the engineered proteins and materials. Specifically, we discuss their utility in bio-orthogonal noncanonical amino acid tagging (BONCAT), fluorescent noncanonical amino acid tagging (FUNCAT), threonine-derived noncanonical amino acid tagging (THRONCAT), cross-linking, fluorination, and enzyme engineering. This review underscores the importance of noncanonical amino acid incorporation as a tool for the development of tailored protein properties to meet diverse research and industrial needs.

Enhancing Enzyme Stability and Functionality: Covalent Immobilization of Trypsin on Magnetic Gum Arabic Modified Fe3O4 Nanoparticles

This study aimed to fabricate gum Arabic (GA)-coated Fe3O4 nanoparticles bearing numerous active aldehyde groups on their surface, followed by an assessment of their capability as a magnetic support for the covalent immobilization of the trypsin enzyme for the first time. FT-IR, XRD, TGA, and SEM results demonstrated the successful synthesis of GA-coated Fe3O4 nanoparticles, along with the covalent immobilization of the enzyme onto the support. Immobilization enhanced the relative enzymatic activity across a range of aqueous solution pH levels (ranging from 4 to 11) and temperatures (ranging from 20 to 80 °C) without altering the optimum pH and temperature for trypsin activity. Kinetic studies using Michaelis-Menten plots revealed changes in kinetic parameters, including a lower Vmax and higher Km for immobilized trypsin compared to the free enzyme. The immobilization onto magnetic gum Arabic nanoparticles resulted in an improved stability of trypsin in the presence of various solvents, maintaining a stability order comparable to that of the free enzyme due to the stabilizing effect of the support. The reusability results showed that the immobilized enzyme can retain over 93% of its activity for up to 15 cycles.

A systematic study on the characteristics and applications of laccases produced by fungi: insights on their potential for biotechnologies

Laccases are polyphenol oxidase enzymes and form the enzyme complex known for their role in wood decomposition and lignin degradation. The present study aimed to systematically review the state-of-the-art trends in scientific publications on laccase enzymes of the last 10 years. The main aspects checked included the laccase-producing fungal genera, the conditions of fungal growth and laccase production, the methods of immobilization, and potential applications of laccase. After applying the systematic search method 177 articles were selected to compound the final database. Although various fungi produce laccase, most studies were Trametes and Pleurotus genera. The submerged fermentation (SmF) has been the most used, however, the use of solid-state fermentation (SSF) appeared as a promising technique to produce laccase when using agro-industrial residues as substrates. Studies on laccase immobilization showed the covalent bonding and entrapment methods were the most used, showing greater efficiency of immobilization and a high number of enzyme reuses. The main use of the laccase was in bioremediation, especially in the discoloration of dyes from the textile industry and the degradation of pharmaceutical waste. Implications and consequences of all these findings in biotechnology and environment, as well as the trends and gaps of laccase research were discussed.

Bioremoval of tannins and heavy metals using immobilized tannase and biomass of Aspergillus glaucus

BACKGROUND

The presence of inorganic pollutants and heavy metals in industrial effluents has become a serious threat and environmental issues. Fungi have a remarkable ability to exclude heavy metals from wastewater through biosorption in eco-friendly way. Tannase plays an important role in bioconversion of tannin, a major constituent of tannery effluent, to gallic acid which has great pharmaceutical applications. Therefore, the aim of the current study was to exploit the potential of tannase from Aspergillus glaucus and fungal biomass waste for the bioremediation of heavy metals and tannin.

RESULTS

Tannase from A. glaucus was partially purified 4.8-fold by ammonium sulfate precipitation (80%). The enzyme was optimally active at pH 5.0 and 40 °C and stable at this temperature for 1 h. Tannase showed high stability at different physiological conditions, displayed about 50% of its activity at 60 °C and pH range 5.0-6.0. Immobilization of tannase was carried out using methods such. as entrapment in Na-alginate and covalent binding to chitosan. The effects of Na-alginate concentrations on the beads formation and enzyme immobilization revealed that maximum immobilization efficiency (75%) was obtained with 3% Na-alginate. A potential reusability of the immobilized enzyme was showed through keeping 70% of its relative activity up to the fourth cycle. The best bioconversion efficiency of tannic acid to gallic acid by immobilized tannase was at 40 °C with tannic acid concentration up to 50 g/l. Moreover, bioremediation of heavy metal (Cr3+, Pb2+, Cu2+, Fe3+, and Mn2+) from aqueous solution using A. glaucus biomass waste was achieved with uptake percentage of (37.20, 60.30, 55.27, 79.03 and 21.13 respectively). The biomass was successfully used repeatedly for removing Cr3+ after using desorbing agent (0.1 N HCl) for three cycles.

CONCLUSION

These results shed the light on the potential use of tannase from locally isolated A. glaucus in the bioremediation of industrial tanneries contained heavy metals and tannin.

Biocatalytic Method for Producing an Affinity Resin for the Isolation of Immunoglobulins

Affinity chromatography is a widely used technique for antibody isolation. This article presents the successful synthesis of a novel affinity resin with a mutant form of protein A (BsrtA) immobilized on it as a ligand. The key aspect of the described process is the biocatalytic immobilization of the ligand onto the matrix using the sortase A enzyme. Moreover, we used a matrix with primary amino groups without modification, which greatly simplifies the synthesis process. The resulting resin shows a high dynamic binding capacity (up to 50 mg IgG per 1 mL of sorbent). It also demonstrates high tolerance to 0.1 M NaOH treatment and maintains its effectiveness even after 100 binding, elution, and sanitization cycles.

Recent Advances and Perspectives on Food-Grade Immobilisation Systems for Enzymes

The use of enzyme immobilisation is becoming increasingly popular in beverage processing, as this method offers significant advantages, such as enhanced enzyme performance and expanded applications, while allowing for easy process termination via simple filtration. This literature review analysed approximately 120 articles, published on the Web of Science between 2000 and 2023, focused on enzyme immobilisation systems for beverage processing applications. The impact of immobilisation on enzymatic activity, including the effects on the chemical and kinetic properties, recyclability, and feasibility in continuous processes, was evaluated. Applications of these systems to beverage production, such as wine, beer, fruit juices, milk, and plant-based beverages, were examined. The immobilisation process effectively enhanced the pH and thermal stability but caused negative impacts on the kinetic properties by reducing the maximum velocity and Michaelis-Menten constant. However, it allowed for multiple reuses and facilitated continuous flow processes. The encapsulation also allowed for easy process control by simplifying the removal of the enzymes from the beverages via simple filtration, negating the need for expensive heat treatments, which could result in product quality losses.

Carboxy-Functionalized Covalent Organic Framework as a Carrier for Lipase Immobilization and Its Application in Inhibitors Screening

Covalent organic frameworks (COFs) with large specific surface areas, high porosity, good stability, and designable structure are promising carriers for immobilized enzymes. It is important to explore lipase inhibitors from natural foods as lipase inhibitors are closely related to the treatment of obesity. In this work, a carboxyl functionalized covalent organic framework (TpBD-3COOH) was prepared by solvothermal method for covalent immobilization of porcine pancreatic lipase (PPL) and obtained the enzyme-decorated COF (PPL@COF). The immobilized lipase showed wider pH and temperature tolerance with the same optimal pH and temperature of 7.5 and 50 ℃ compared to free lipase. After 6 successive reuses, the PPL@COF maintained 53.0% of its original activity. Immobilized lipase also displayed enhanced storage stability (55.4% after 14 days at 4 ℃). When p-nitrophenyl acetate was applied as the substrate, the calculated Michaelis constant was 3.57 mM and the half maximal inhibitory concentration of orlistat was 3.20 μM. Finally, the PPL@COF was used for enzyme inhibitors screening from natural foods combined with UV spectrophotometry, and Hawthorn was screened for excellent lipase inhibitory activity.

Bioremediation and bioscavenging for elimination of organophosphorus threats: An approach using enzymatic advancements

Organophosphorus compounds (OP) are highly toxic pesticides and nerve agents widely used in agriculture and chemical warfare. The extensive use of these chemicals has severe environmental implications, such as contamination of soil, water bodies, and food chains, thus endangering ecosystems and biodiversity. Plants absorb pesticide residues, which then enter the food chain and accumulate in the body fat of both humans and animals. Numerous human cases of OP poisoning have been linked to both acute and long-term exposure to these toxic OP compounds. These compounds inhibit the action of the acetylcholinesterase enzyme (AChE) by phosphorylation, which prevents the breakdown of acetylcholine (ACh) neurotransmitter into choline and acetate. Thus, it becomes vital to cleanse the environment from these chemicals utilizing various physical, chemical, and biological methods. Biological methods encompassing bioremediation using immobilized microbes and enzymes have emerged as environment-friendly and cost-effective approaches for pesticide removal. Cell/enzyme immobilized systems offer higher stability, reusability, and ease of product recovery, making them ideal tools for OP bioremediation. Interestingly, enzymatic bioscavengers (stoichiometric, pseudo-catalytic, and catalytic) play a vital role in detoxifying pesticides from the human body. Catalytic bioscavenging enzymes such as Organophosphate Hydrolase, Organophosphorus acid anhydrolase, and Paraoxonase 1 show high degradation efficiency within the animal body as well as in the environment. Moreover, these enzymes can also be employed to decontaminate pesticides from food, ensuring food safety and thus minimizing human exposure. This review aims to provide insights to potential collaborators in research organizations, government bodies, and industries to bring advancements in the field of bioremediation and bioscavenging technologies for the mitigation of OP-induced health hazards.

Termostable and effective immobilized invertase for sucrose determination in fruit juices

In this study, immobilization of invertase enzyme was performed on a previously synthesized and characterized poly(N-vinylpyrrolidone-co-butylacrylate-co-N hydroxymethylacrylamide) terpolymer membranes by covalent bonding method. Glutaraldehyde(GA) was used as the crosslinker and Bovine Serum Albumin(BSA) was used as the binding agent. Optimum pH, temperature, amount of polymer, substrate concentration, amount of BSA and amount of GA values were determined for both free and immobilized enzyme. Optimum pH and temperature values were found as pH = 5.0, T = 55 °C, pH = 7.0 and T = 80 °C for free and immobilized enzyme, respectively. In particular, the optimum temperature of 80 °C for the immobilized enzyme provides its potential to be used commercially. The kinetic parameters of the free enzyme and the immobilized enzyme were determined using the well known Lineweaver-Burk method. The Vmax values for free (13.4 μM/min) and immobilized enzyme (12.2 μM/min) were found as close to each other, while the Km value of the immobilized enzyme (8.33 mM) was much lower than that of the free enzyme (29.41 mM). In reuse studies conducted with peach and orange juices, it was determined that the immobilized enzyme retained approximately 90% of its activity even after 30 reuses within 1 month.

Industrial Approach to Invertase Production from Fruit Waste for Enhanced Efficiency and Conservation

This study investigates the commercial viability of repurposing fruit waste for enzyme production, specifically focusing on the invertase enzyme derived from Saccharomyces cerevisiae. By utilizing fruit pulp that incorporates mulberry, carob, Figure, and grape pulp as a nutrient source, it is observed that the culture medium containing carob pulp exhibits the highest invertase activity. Specifically, the invertase activity in this medium is approximately 2.5 times greater (12.90 U/mg protein) than that observed in the peptone medium (5.98 U/mg protein). The extract undergoes several purification steps, including ultrafiltration, ammonium sulfate precipitation, dialysis, and ion-exchange chromatography (purification ratio: 12.11 times, yield: 26.93%). The purified enzyme is immobilized using alginate beads, improving pH and thermal stability. The immobilized enzyme exhibits optimal activity between pH 3.50 and pH 7.00, thereby broadening the enzyme's high-activity pH range. The thermal stability of the immobilized invertase enzyme is significantly improved, especially at 65 °C. Activity studies in the presence of metal ions and certain chemicals have been conducted. The immobilized enzyme's activity increases by approximately 40% in the presence of Ca2+ and Mg2+, and the immobilized enzyme maintains its activity in the presence of detergents such as SDS, Tween-20, and organic solvents like ethanol and methanol. The potential for the reuse of immobilized invertase was investigated under standard assay conditions. After 20 cycles, the immobilized enzyme was found to retain 80% of its initial activity. Overall, the study establishes the commercial potential of fruit pulp, typically discarded in fruit juice production, as a valuable source for obtaining an invertase enzyme. Furthermore, this study also aims to develop a suitable purification process for invertase in the fruit juice industry. By harnessing fruit waste and implementing innovative enzyme production strategies, industries can enhance their efficiency, reduce their environmental footprint, and optimize resource utilization.

Polyurethane degradation by extracellular urethanase producing bacterial isolate Moraxella catarrhalis strain BMPPS3

Plastic waste has become a global issue and a threat to the ecosystem. The present study isolated polyurethane (PU) degrading bacterial species from soil dumped with plastic wastes. Four bacterial isolates, RS1, RS6, RS9 and RS13 were obtained and their ability to degrade PU in a synthetic medium with PU as a sole source of carbon was assessed individually. After thirty days of incubation, the highest PU weight loss of 67.36 ± 0.32% was recorded in the medium containing RS13 isolate. The results of FTIR revealed the occurrence of carbonyl peaks. The putative isolate RS13 confirmed with the genus Moraxella according to 16S rRNA gene sequencing and the isolate was specified as Moraxella catarrhalis strain BMPPS3. The restriction analysis of Moraxella catarrhalis strain BMPPS3 revealed that the GCAT content to 51% and 49% correspondingly. Moraxella catarrhalis strain BMPPS3 was able to colonize on PU surface and form a biofilm as revealed by SEM investigation. Fatty acids and alkanes were found to be the degradation products by GC-MS analysis. The presence of these metabolites facilitated the growth of strain RS13 and suggested that ester hydrolysis products had been mineralized into CO2 and H2O. Extracellular biosurfactant synthesis has also been found in Moraxella catarrhalis strain BMPPS13 inoculated with synthetic media and mineral salt media containing PU and glucose as carbon sources, respectively with a significant level of cell-surface hydrophobicity (32%). The production and activity of extracellular esterase showed consistent increase from day 1-15 which peaked (1.029 mM/min/mg) on day 24 significantly at P < 0.001. Crude biosurfactants were lipopeptide-based, according to the characteristic investigation. According to this study findings, Moraxella catarrhalis produces biosurfactants of the esterase, urethanase and lipase (lipopeptide) types when carbon source PU is present.

Application of Immobilized β-Glucosidase from Candida boidinii in the Hydrolysis of Delignified Sugarcane Bagasse

Candida boidinii is a methylotrophic yeast with wide geographical distribution. In the present study, the microorganism was isolated from the Bahian semiarid and the enzymatic extract containing β-glucosidase was obtained through submerged fermentation. Response surface methodology was employed to optimize of fermentation medium. The higher production of β-glucosidase was obtained after 71 h of fermentation in an optimized medium composed of 3.35% glucose, 1.78% yeast extract and 1% peptone. The optimum pH and temperature of enzymatic activity were 6.8 (citrate-phosphate buffer) and 71.7 °C, respectively. Salts tested (10 mM) CaCl2, Na2SO4 and ZnSO4 promotes the increase of 91%, 45% and 80% of activity, respectively. The enzyme retained 64% ± 2.3 of its initial activity after 1 h heating at 90 °C. The production of reducing sugars was 95.94% after 24 h of hydrolysis and, with the addition of metal ions, this value increased more than 2 times. Among the supports analyzed for immobilization, chitosan showed higher residual activity during reuse. The immobilized enzyme showed higher activity at 60 °C with pH 6 and preserved almost 100% of the initial activity after 30 min at 70 °C.

Advances in surface design and biomedical applications of magnetic nanoparticles

Despite significant efforts by scientists in the development of advanced nanotechnology materials for smart diagnosis devices and drug delivery systems, the success of clinical trials remains largely elusive. In order to address this biomedical challenge, magnetic nanoparticles (MNPs) have gained attention as a promising candidate due to their theranostic properties, which allow the simultaneous treatment and diagnosis of a disease. Moreover, MNPs have advantageous characteristics such as a larger surface area, high surface-to-volume ratio, enhanced mobility, mass transference and, more notably, easy manipulation under external magnetic fields. Besides, certain magnetic particle types based on the magnetite (Fe3O4) phase have already been FDA-approved, demonstrating biocompatible and low toxicity. Typically, surface modification and/or functional group conjugation are required to prevent oxidation and particle aggregation. A wide range of inorganic and organic molecules have been utilized to coat the surface of MNPs, including surfactants, antibodies, synthetic and natural polymers, silica, metals, and various other substances. Furthermore, various strategies have been developed for the synthesis and surface functionalization of MNPs to enhance their colloidal stability, biocompatibility, good response to an external magnetic field, etc. Both uncoated MNPs and those coated with inorganic and organic compounds exhibit versatility, making them suitable for a range of applications such as drug delivery systems (DDS), magnetic hyperthermia, fluorescent biological labels, biodetection and magnetic resonance imaging (MRI). Thus, this review provides an update of recently published MNPs works, providing a current discussion regarding their strategies of synthesis and surface modifications, biomedical applications, and perspectives.

Lipase in-situ immobilized in covalent organic framework: Enzymatic properties and application in the preparation of 1, 3-dioleoyl-2-palmitoylglycerol

In this study, the critical importance of designing an appropriate immobilized carrier and method for free lipase to ensure exceptional biological catalytic activity and stability was emphasized. Covalent organic frameworks (COF-1) were synthesized as a novel porous carrier with an azine structure (-CN-NC-) through the condensation of hydrazine hydrate and benzene-1,3,5-tricarbaldehyde at room temperature. Simultaneously, Rhizomucor miehei lipase (RML) was immobilized within the COF-1 carrier using an in-situ aqueous phase method. Characterization of the carrier and RML@COF-1 and evaluation of the lipase properties of RML and RML@COF-1 through p-Nitrophenyl palmitate hydrolysis were conducted. Additionally, application in the synthesis of 1, 3-dioleoyl-2-palmitoylglycerol (OPO) was explored. The results showed that RML@COF-1 exhibited a high enzymatic loading of 285.4 mg/g. Under 60℃ conditions, the activity of RML@COF-1 was 2.31 times higher than that of free RML, and RML@COF-1 retained 77.25% of its original activity after 10 cycles of repeated use, indicating its excellent thermal stability and repeatability. Under the optimal conditions (10%, 1:8 PPP/OA, 45℃, 5 h), the yield of OPO reached 47.35%, showcasing the promising application prospects of the novel immobilized enzyme synthesized via in-situ aqueous phase synthesis for OPO preparation.

Advancements in enzyme immobilization on magnetic nanomaterials: toward sustainable industrial applications

Enzymes are widely used in biofuels, food, and pharmaceuticals. The immobilization of enzymes on solid supports, particularly magnetic nanomaterials, enhances their stability and catalytic activity. Magnetic nanomaterials are chosen for their versatility, large surface area, and superparamagnetic properties, which allow for easy separation and reuse in industrial processes. Researchers focus on the synthesis of appropriate nanomaterials tailored for specific purposes. Immobilization protocols are predefined and adapted to both enzymes and support requirements for optimal efficiency. This review provides a detailed exploration of the application of magnetic nanomaterials in enzyme immobilization protocols. It covers methods, challenges, advantages, and future perspectives, starting with general aspects of magnetic nanomaterials, their synthesis, and applications as matrices for solid enzyme stabilization. The discussion then delves into existing enzymatic immobilization methods on magnetic nanomaterials, highlighting advantages, challenges, and potential applications. Further sections explore the industrial use of various enzymes immobilized on these materials, the development of enzyme-based bioreactors, and prospects for these biocatalysts. In summary, this review provides a concise comparison of the use of magnetic nanomaterials for enzyme stabilization, highlighting potential industrial applications and contributing to manufacturing optimization.

Effective Soybean Oil Degumming by Immobilized Phospholipases A2 from Walterinnesia aegyptia Venom

Enzymatic degumming utilizing phospholipase enzymes could be used in ecologically friendly procedures with enhanced oil recovery yields. In this study, two phospholipases A2 of group I and II, WaPLA2-I and WaPLA2-II, from the snake venom of Saudi Walterinnesia aegyptia were evaluated for soybean oil degumming after being immobilized on three different support materials (calcium alginate (CA), CA-gelatin (CAG), and CA-chitosan (CAC), and cross-linked with glutaraldehyde). Higher yields of CAC-immobilized PLA2-I (85 ± 3%) and PLA2-II (87 ± 3.6%) compared to CAG (77.3 ± 2.1 and 79 ± 2.6%, respectively) and CA beads (55.7 ± 2.5% and 57.3 ± 3.1%, respectively) were observed. In addition, the optimal temperature of immobilized WaPLA2-I and WaPLA2-II increased from 45 to 55 °C and from 55 to 65 °C, respectively. Their stability at high temperatures was also significantly enhanced covering a larger range (70-80 °C). Likewise, the pH/activity profile of WaPLA2 was greatly expanded upon immobilization with the pH-optima being shifted by 0.5 to 1 pH unit to the basic side. Similarly, the stability of WaPLA2s in the presence of organic solvents was also significantly improved, while the affinity for calcium and bile salt was the same for both free and immobilized enzymes. Interestingly, the remaining activity of immobilized WaPLA2 onto different supports was more than 50 or 60% after eight recycles or 120 days of storage at 4 °C, respectively. CAC-WaPLA2-II was the best immobilized enzyme complex for the oil degumming process by reducing its final residual phosphorus content from 168 mg/kg to less than 10 mg/kg in only 4 h. Overall, CAC-WaPLA2-II showed the most attractive profiles of temperature, pH, and reaction duration as well as significant storage stability and reusability.

Microbial electrosynthesis of valuable chemicals from the reduction of CO2: a review

The present energy demand of the world is increasing but the fossil fuels are gradually depleting. As a result, the need for alternative fuels and energy sources is growing. Fuel cells could be one alternative to address the challenge. The fuel cell can convert CO2 to value-added chemicals. The potential of bio-fuel cells, specifically enzymatic fuel cells and microbial fuel cells, and the importance of immobilization technology in bio-fuel cells are highlighted. The review paper also includes a detailed explanation of the microbial electrosynthesis system to reduce CO2 and the value-added products during microbial electrosynthesis. Future research in bio-electrochemical synthesis for CO2 conversion is expected to prioritize enhancing biocatalyst efficiency, refining reactor design, exploring novel electrode materials, understanding microbial interactions, integrating renewable energy sources, and investigating electrochemical processes for carbon capture and selective CO2 reduction. The challenges and perspectives of bio-electrochemical systems in the application of CO2 conversion are also discussed. Overall, this review paper provides valuable insights into the latest developments and criteria for effective research and implementation in bio-fuel cells, immobilization technology, and microbial electro-synthesis systems.

One-Pot Synthesis of 1,3,5-Trisubstitued Pyrazoles via Immobilized Thermomyces lanuginosus Lipase (TLL) on a Metal-Organic Framework

A regioselective enzyme-catalyzed system is selected for the synthesis of 1,3,5-trisubstituted pyrazole derivatives by adding phenyl hydrazines, nitroolefins, and benzaldehydes. The reaction is performed in a one-pot vessel with a yield ranging from 49 to 90%. TLL@MMI, immobilized Thermomyces lanuginosus lipase (TLL) on a multivariate of MOF-5/IRMOF-3 (MMI), showed good performance for the catalysis of this reaction. The prepared biocatalyst was characterized by FTIR, XRD, SEM, and EDX. The thermal and solvent stability of TLL@MMI was investigated in MeOH and EtOH after 24 h incubation. In the presence of 100% concentrations of EtOH, TLL@MMI has 80% activity.

Proteases: Importance, Immobilization Protocols, Potential of Activated Carbon as Support, and the Importance of Modifying Supports for Immobilization

Although enzymes have been used for thousands of years, their application in industrial processes has gained importance since the 20th century due to technological and scientific advances in several areas, including biochemistry [...].

Enzymatic Performance of Aspergillus oryzae α-Amylase in the Presence of Organic Solvents: Activity, Stability, and Bioinformatic Studies

Enzymatic reactions can be modulated by the incorporation of organic solvents, leading to alterations in enzyme stability, activity, and reaction rates. These solvents create a favorable microenvironment that enables hydrophobic reactions, facilities enzyme-substrate complex formation, and reduces undesirable water-dependent side reactions. However, it is crucial to understand the impact of organic solvents on enzymatic activity, as they can also induce enzyme inactivation. In this study, the enzymatic performance of Aspergillus oryzae α-amylase (Taka-amylase) in various organic solvents both experimentally and computationally was investigated. The results demonstrated that ethanol and ether sustain Taka-amylase activity up to 20% to 25% of the organic solvents, with ether providing twice the stability of ethanol. Molecular dynamics simulations further revealed that Taka-amylase has a more stable structure in ether and ethanol relative to other organic solvents. In addition, the analysis showed that the loop located near the active site in the AB-domain is a vulnerable site for enzyme destabilization when exposed to organic solvents. The ability of Taka-amylase to preserve the secondary loop structure in ether and ethanol contributed to the enzyme's activity. In addition, the solvent accessibility surface area of Taka-amylase is distributed throughout all enzyme structures, thereby contributing to the instability of Taka-amylase in the presence of most organic solvents.

Rapid and Mechanically Robust Immobilization of Proteins on Silica Studied at the Single-Molecule Level by Force Spectroscopy and Verified at the Macroscopic Level

Typical methods for stable immobilization of proteins often involve time-consuming surface modification of silicon-based materials to enable specific binding, while the nonspecific adsorption method is faster but usually unstable. Herein, we fused a silica-binding protein, Si-tag, to target proteins so that the target proteins could attach directly to silica substrates in a single step, markedly streamlining the immobilization process. The adhesion force between the Si-tag and glass substrates was determined to be approximately 400-600 pN at the single-molecule level by atomic force microscopy, which is greater than the unfolding force of most proteins. The adhesion force of the Si-tag exhibits a slight increase when pulled from the C-terminus compared to that from the N-terminus. Furthermore, the Si-tag's adhesion force on a glass surface is marginally higher than that on a silicon nitride probe. The binding properties of the Si-tag are not obviously affected by environmental factors, including pH, salt concentration, and temperature. In addition, the macroscopic adhesion force between the Si-tag-coated hydrogel and glass substrates was ∼40 times higher than that of unmodified hydrogels. Therefore, the Si-tag, with its strong silica substrate binding ability, provides a useful tool as an excellent fusion tag for the rapid and mechanically robust immobilization of proteins on silica and for the surface coating of silica-binding materials.

Immobilization of microbial multienzyme preparation on calcium alginate beads as well as lyophilization with mosambi peel matrix improved its shelf-life and stability

The purpose of the current study was to evaluate the functional activity and storage viability (at 4 °C and 35 °C) of an immobilized as well as lyophilized multienzyme, viz., pectinase, cellulase, and amylase (PCA) that was produced by Bacillus subtilis NG105 under solid state fermentation (SSF) at 35 ℃ for 10 days using mosambi peel as a substrate. After SSF, the culture media was divided into two aliquots. From the first aliquot, the produced ME was extracted, precipitated, and further immobilized on calcium alginate beads (MEICA). In order to immobilize on mosambi peel matrix, the second aliquot was mixed with acetone and subsequently lyophilized (MELMP). Thus, ready MEICA and MELMP extracted 87.5 and 91.5% juice from mango pulp, respectively. In the reusability study, after 5 cycles, MEICA exhibited 23.8%, 24.4%, and 36.5% PCA activity, respectively. The PCA activity of MEICA and MELMP was examined after 60 days of storage at 4 ℃. The result revealed that the PCA for MEICA declined from 100 to 66%, 58.2%, and 64.5%, respectively, while for MELMP, it dropped from 100 to 84.2%, 82.1%, and 69.7%, respectively. Further, after 60 days of storage, the reduction of total protein content (TPC) in free multienzyme (FME), MEICA, and MELMP was 92.2%, 91.5%, and 36.3% observed, respectively. In the localization study, the maximum levels of multienzyme activity were found in cell exudates. This study demonstrated that immobilizing of multienzyme through lyophilization on waste substrates like mosambi peel boosted its stability and shelf-life along with greatly reducing the cost of products.

Engineering functional materials through bacteria-assisted living grafting

Functionalizing materials with biomacromolecules such as enzymes has broad applications in biotechnology and biomedicine. Here, we introduce a grafting method mediated by living cells to functionalize materials. We use polymeric scaffolds to trap engineered bacteria and micron-sized particles with chemical groups serving as active sites for grafting. The bacteria synthesize the desired protein for grafting and autonomously lyse to release it. The released functional moieties are locally grafted onto the active sites, generating the materials engineered by living grafting (MELGs). MELGs are resilient to perturbations because of both the bonding and the regeneration of functional domains synthesized by living cells. The programmability of the bacteria enables us to fabricate MELGs that can respond to external input, decompose a pollutant, reconstitute synthetic pathways for natural product synthesis, and purify mismatched DNA. Our work establishes a bacteria-assisted grafting strategy to functionalize materials with a broad range of biological activities in an integrated, flexible, and modular manner. A record of this paper's transparent peer review process is included in the supplemental information.

Magnetic Multienzyme@Metal-Organic Material for Sustainable Biodegradation of Insoluble Biomass

Biodegradation of insoluble biomass such as cellulose via carbohydrase enzymes is an effective approach to break down plant cell walls and extract valuable materials therein. Yet, the high cost and poor reusability of enzymes are practical concerns. We recently proved that immobilizing multiple digestive enzymes on metal-organic materials (MOMs) allows enzymes to be reused via gravimetric separation, improving the cost efficiency of cereal biomass degradation [ACS Appl. Mater. Interfaces 2021, 13, 36, 43085-43093]. However, this strategy cannot be adapted for enzymes whose substrates or products are insoluble (e.g., cellulose crystals). Recently, we described an alternative approach based on magnetic metal-organic frameworks (MOFs) using model enzymes/substrates [ACS Appl. Mater. Interfaces 2020, 12, 37, 41794-41801]. Here, we aim to prove the effectiveness of combining these two strategies in cellulose degradation. We immobilized multiple carbohydrase enzymes that cooperate in cellulose degradation via cocrystallization with Ca2+, a carboxylate ligand (BDC) in the absence and presence of magnetic nanoparticles (MNPs). We then compared the separation efficiency and enzyme reusability of the resultant multienzyme@Ca-BDC and multienzyme@MNP-Ca-BDC composites via gravimetric and magnetic separation, respectively, and found that, although both composites were effective in cellulose degradation in the first round, the multienzyme@MNP-Ca-BDC composites displayed significantly enhanced reusability. This work provides the first experimental demonstration of using magnetic solid supports to immobilize multiple carbohydrase enzymes simultaneously and degrade cellulose and promotes green/sustainable chemistry in three ways: (1) reusing the enzymes saves energy/sources to prepare them, (2) the synthetic conditions are "green" without generating unwanted wastes, and (3) using our composites to degrade cellulose is the first step of extracting valuable materials from sustainable biomasses such as plants whose growth does not rely on nonregeneratable resources.

A Protocol for Custom Biomineralization of Enzymes in Metal-Organic Frameworks (MOFs)

Enzyme immobilization offers a number of advantages that improve biocatalysis; however, finding a proper way to immobilize enzymes is often a challenging task. Implanting enzymes in metal-organic frameworks (MOFs) via co-crystallization, also known as biomineralization, provides enhanced reusability and stability with minimal perturbation and substrate selectivity to the enzyme. Currently, there are limited metal-ligand combinations with a proper protocol guiding the experimental procedures. We have recently explored 10 combinations that allow custom immobilization of enzymes according to enzyme stability and activity in different metals/ligands. Here, as a follow-up of that work, we present a protocol for how to carry out custom immobilization of enzymes using the available combinations of metal ions and ligands. Detailed procedures to prepare metal ions, ligands, and enzymes for their co-crystallization, together with characterization and assessment, are discussed. Precautions for each experimental step and result analysis are highlighted as well. This protocol is important for enzyme immobilization in various research and industrial fields. Key features • A wide selection of metal ions and ligands allows for the immobilization of enzymes in metal-organic frameworks (MOFs) via co-crystallization. • Step-by-step enzyme immobilization procedure via co-crystallization of metal ions, organic linkers, and enzymes. • Practical considerations and experimental conditions to synthesize the enzyme@MOF biocomposites are discussed. • The demonstrated method can be generalized to immobilize other enzymes and find other metal ion/ligand combinations to form MOFs in water and host enzymes.

Enzyme immobilization on α-1,3-glucan: development of flow reactor with fusion protein of α-1,3-glucan binding domains and histamine dehydrogenase

α-1,3-Glucanase Agl-KA from Bacillus circulans KA-304 consists of a discoidin domain (DS1), a carbohydrate binding module family 6 (CBM6), a threonine-proline-rich-linker (TP linker), a discoidin domain (DS2), an uncharacterized domain, and a catalytic domain. The binding of DS1, CBM6, and DS2 to α-1,3-glucan can be improved in the presence of two of these three domains. In this study, DS1, CBM6, and TP linker were genetically fused to histamine dehydrogenase (HmDH) from Nocardioides simplex NBRC 12069. The fusion enzyme, AGBDs-HmDH, was expressed in Escherichia coli Rosetta 2 (DE3) and purified from the cell-free extract. AGBDs-HmDH bound to 1% micro-particle of α-1,3-glucan (diameter: less than 1 μm) and 7.5% coarse-particle of α-1,3-glucan (less than 200 μm) at about 97 % and 70% of the initial amounts of the enzyme, respectively. A reactor for flow injection analysis filled with AGBDs-HmDH immobilized on the coarse-particle of α-1,3-glucan was successfully applied to determine histamine. A linear calibration curve was observed in the range for about 0.1 to 3.0 mM histamine. These findings suggest that the combination of α-1,3-glucan and α-1,3-glucan binding domains is a candidate for novel enzyme immobilization.

Exploration of the structural mechanism of hydrogen (H2)-promoted horseradish peroxidase (HRP) activity via multiple spectroscopic and molecular dynamics simulation techniques

Horseradish peroxidase (HRP) is an enzyme that is widely used in various fields. In this study, the effects of molecular hydrogen (H2) on the activity and structural characteristics of HRP were investigated by employing multiple spectroscopic techniques, atomic force microscopy (AFM) and molecular dynamics (MD) simulations. The results demonstrated that H2 could enhance HRP activity, especially in 1.5 mg/L hydrogen-rich water (HRW). The structural analysis results showed that H2 might alter HRP activity by affecting the active sites, secondary structure, hydrogen bonding network, CS groups, and morphological characteristics. The MD results also confirmed that H2 could increase the FeN bond distance in the active site, affect the secondary structure, and increase the number of hydrogen bonds. The MD results further suggested that H2 could increase the number of salt bridges, and lengthen the SS bonds in HRP. This study primarily revealed the mechanism by which H2 enhances the HRP activity, providing insight into the interactions between gas and macromolecular proteins. However, some of the results obtained via MD simulations still need to be verified experimentally. In addition, our study also provided a new convenient strategy to enhance enzyme activity.

Region-Directed Enzyme Immobilization through Engineering Protein Surface with Histidine Clusters

Enzyme immobilization is a key enabling technology for a myriad of industrial applications, yet immobilization science is still too empirical to reach highly active and robust heterogeneous biocatalysts through a general approach. Conventional protein immobilization methods lack control over how enzymes are oriented on solid carriers, resulting in negative conformational changes that drive enzyme deactivation. Site-selective enzyme immobilization through peptide tags and protein domains addresses the orientation issue, but this approach limits the possible orientations to the N- and C-termini of the target enzyme. In this work, we engineer the surface of two model dehydrogenases to introduce histidine clusters into flexible regions not involved in catalysis, through which immobilization is driven. By varying the position and the histidine density of the clusters, we create a small library of enzyme variants to be immobilized on different carriers functionalized with different densities of various metal chelates (Co2+, Cu2+, Ni2+, and Fe3+). We first demonstrate that His-clusters can be as efficient as the conventional His-tags in immobilizing enzymes, recovering even more activity and gaining stability against some denaturing agents. Furthermore, we find that the enzyme orientation as well as the type and density of the metal chelates affect the immobilization parameters (immobilization yield and recovered activity) and the stability of the immobilized enzymes. According to proteomic studies, His-clusters enable a different enzyme orientation as compared to His-tag. Finally, these oriented heterogeneous biocatalysts are implemented in batch reactions, demonstrating that the stability achieved by an optimized orientation translates into increased operational stability.

Role of Clay Substrate Molecular Interactions in Some Dairy Technology Applications

The use of clay materials in dairy technology requires a multidisciplinary approach that allows correlating clay efficiency in the targeted application to its interactions with milk components. For profitability reasons, natural clays and clay minerals can be used as low-cost and harmless food-compatible materials for improving key processes such as fermentation and coagulation. Under chemical stability conditions, clay materials can act as adsorbents, since anionic clay minerals such as hydrotalcite already showed effectiveness in the continuous removal of lactic acid via in situ anion exchange during fermentation and ex situ regeneration by ozone. Raw and modified bentonites and smectites have also been used as adsorbents in aflatoxin retention and as acidic species in milk acidification and coagulation. Aflatoxins and organophilic milk components, particularly non-charged caseins around their isoelectric points, are expected to display high affinity towards high silica regions on the clay surface. Here, clay interactions with milk components are key factors that govern adsorption and surface physicochemical processes. Knowledge about these interactions and changes in clay behavior according to the pH and chemical composition of the liquid media and, more importantly, clay chemical stability is an essential requirement for understanding process improvements in dairy technology, both upstream and downstream of milk production. The present paper provides a comprehensive review with deep analysis and synthesis of the main findings of studies in this area. This may be greatly useful for mastering milk processing efficiency and envisaging new prospects in dairy technology.

Cyclic extraction of phosphate from soybean meal using immobilized Aspergillus oryzae SBS50 phytase

Phytase enzyme found in plants, animals, and microorganisms is mainly involved in catalyzing the systematic removal of a phosphate group from phytic acid. Enzyme immobilization is one of the cost-effective methods for the wide usage of enzymes in the industrial sector. This paper reports the covalent immobilization of phytase on glutaraldehyde-activated aluminum oxide beads. The immobilization yield, efficiency, and activation energy were found to be 47.8%, 71.5%, and 15.78 J/mol, respectively. The bound enzyme displayed a shift in pH optima from 5.5 to 4.5, which is more beneficial to increase digestibility in comparison with the free enzyme. Immobilized phytase retained 42.60% of its activity after 1.0 h incubation at 80 °C, whereas free enzyme retained only 4.20% of its activity. Thermodynami increase in half-lives, D-values, enthalpy and free energy change after covalent immobilization could be credited to the enhanced stability. Immobilized phytase could be reused for five consecutive cycles retaining 51% of its initial activity with sodium phytate. The immobilized phytase was also found effective to hydrolyze the soybean meal, thus increasing the digestibility of poultry feed. The hydrolyzing reaction of soybean meal was carried out for six consecutive cycles and immobilized phytase retained nearly 50% of activity till the fifth cycle. The amount of phosphorus released after treatment with immobilized phytase was far higher than that from free phytase. Immobilization on this support is significant, as this support can sustain high mechanical resistance at high pH and temperature. This considerable stability and reusability of the bound enzyme may be advantageous for its industrial application.

Designing Ubiquitin-like protease 1 (Ulp1) based nano biocatalysts: A promising technology for SUMO fusion proteins

The SUMO proteases (Ulps), a group of cysteine proteases, are well known for their efficient ability to perform structure-based cleavage of SUMO tag from the protein of interest and generation of biotherapeutics with authentic N-terminus. However, the stability of Ulps has remained a challenge for the economical production of difficult-to-produce proteins in E. coli. Therefore, the present study aimed to establish the methodology for developing stable S. pombe Ulp1 preparation using different enzyme immobilization strategies. The whole-cell biocatalyst developed using the Pir1 anchor protein of Pichia cleaved the SUMO tag within 24 h of reaction incubation. The chemical immobilization using commercial epoxy and amino methacrylate beads significantly enhanced the operational reusability of SpUlp1 up to 24 cycles. Silica beads further improved the repetitive usage of the immobilized enzyme for 65 cycles. The SpUlp1 immobilization on laboratory-developed chitosan-coated iron oxide nanoparticles exhibited more than 90 % cleavage of SUMO tag from different substrates even after 100 consecutive reactions. Moreover, an effective SUMO tag removal was observed within 10 min of incubation. The operational stability of the immobilized enzyme was confirmed in a pH range of 5 to 13. The spherical nature of nanoparticles was confirmed by FESEM and TEM results. The successful chitosan coating and subsequent activation with glutaraldehyde were established via FT-IR. Furthermore, HRTEM, SAED, and XRD proved the crystalline nature of nanoparticles, while VSM confirmed the superparamagnetic behavior.

Application of electrospun chitosan-based nanofibers as immobilization matrix for biomolecules

Nanofiber meshes from electrospun chitosan, highly modified with biotin and arylazides, are well-suited for application as enzyme immobilization matrices. To test this, catalytically active biomolecules were immobilized onto photocrosslinked nanofibrous nonwovens consisting mainly of biotinylated fungal chitosan and a small amount (10 w%) of poly ethylene oxide. In this study, we show that over 10 μg eugenol oxidase per milligram dry polymer matrix can be loaded on UV-crosslinked chitosan nanofibers. We further demonstrate that bound enzyme activity can be fully retained for over 7 days of storage at ambient conditions in aqueous buffer. Samples loaded at maximum enzyme carrying capacity were tested in a custom-made plug-flow reactor system with online UV-VIS spectroscopy for activity determination. High wettability and durability of the hydrophilic chitosan support matrix enabled continuous oxidation of model substrate vanillyl alcohol into vanillin with constant turnover at flow rates of up to 0.24 L/h for over 6 h. This proves the above hypothesis and enables further application of the fibers as stacked microfluidic membranes, biosensors, or structural starting points for affinity crosslinked enzyme gels. KEY POINTS: • Biotinylated chitosan-based nanofibers retain enzymes via mild affinity interactions • Immobilized eugenol oxidase shows high activity and resists continuous washing • Nanofiber matrix material tolerated high flow rates in a continuous-flow setup.

Recent advances in nanobiosensors for sustainable healthcare applications: A systematic literature review

The need for novel healthcare treatments and drugs has increased due to the expanding human population, detection of newer diseases, and looming pandemics. The development of nanotechnology offers a platform for cutting-edge in vivo non-invasive monitoring and point-of-care-testing (POCT) for rehabilitative disease detection and management. The advancement and uses of nanobiosensors are currently becoming more common in a variety of scientific fields, such as environmental monitoring, food safety, biomedical, clinical, and sustainable healthcare sciences, since the advent of nanotechnology. The identification and detection of biological patterns connected to any type of disease (communicable or not) have been made possible in recent years by several sensing techniques utilizing nanotechnology concerning biosensors and nanobiosensors. In this work, 2218 articles are drawn and screened from six digital databases out of which 17 were shortlisted for this review by using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) technique. As a result, this study uses a systematic methodology to review some recently developed extremely sensitive nanobiosensors, along with their biomedical, point-of-care diagnostics (POCD), or healthcare applications and their capabilities, particularly for the prediction of some fatal diseases based on a few of the most recent publications. The potential of nanobiosensors for medicinal, therapeutic, or other sustainable healthcare applications, notably for ailments diagnostics, is also recognized as a way forward in the manifestation of future trends.

Oxidoreductase enzymes: Characteristics, applications, and challenges as a biocatalyst

Oxidoreductases are enzymes with distinctive characteristics that favor their use in different areas, such as agriculture, environmental management, medicine, and analytical chemistry. Among these enzymes, oxidases, dehydrogenases, peroxidases, and oxygenases are very interesting. Because their substrate diversity, they can be used in different biocatalytic processes by homogeneous and heterogeneous catalysis. Immobilization of these enzymes has favored their use in the solution of different biotechnological problems, with a notable increase in the study and optimization of this technology in the last years. In this review, the main structural and catalytical features of oxidoreductases, their substrate specificity, immobilization, and usage in biocatalytic processes, such as bioconversion, bioremediation, and biosensors obtainment, are presented.

Cellulase immobilization to enhance enzymatic hydrolysis of lignocellulosic biomass: An all-inclusive review

Cellulase-mediated lignocellulosic biorefinery plays a crucial role in the production of high-value biofuels and chemicals, with enzymatic hydrolysis being an essential component. The advent of cellulase immobilization has revolutionized this process, significantly enhancing the efficiency, stability, and reusability of cellulase enzymes. This review offers a thorough analysis of the fundamental principles underlying immobilization, encompassing various immobilization approaches such as physical adsorption, covalent binding, entrapment, and cross-linking. Furthermore, it explores a diverse range of carrier materials, including inorganic, organic, and hybrid/composite materials. The review also focuses on emerging approaches like multi-enzyme co-immobilization, oriented immobilization, immobilized enzyme microreactors, and enzyme engineering for immobilization. Additionally, it delves into novel carrier technologies like 3D printing carriers, stimuli-responsive carriers, artificial cellulosomes, and biomimetic carriers. Moreover, the review addresses recent obstacles in cellulase immobilization, including molecular-level immobilization mechanism, diffusion limitations, loss of cellulase activity, cellulase leaching, and considerations of cost-effectiveness and scalability. The knowledge derived from this review is anticipated to catalyze the evolution of more efficient and sustainable biocatalytic systems for lignocellulosic biomass conversion, representing the current state-of-the-art in cellulase immobilization techniques.

Current status of carbon monoxide dehydrogenases (CODH) and their potential for electrochemical applications

Anthropogenic carbon dioxide (CO2) levels are rising to alarming concentrations in earth's atmosphere, causing adverse effects and global climate changes. In the last century, innovative research on CO2 reduction using chemical, photochemical, electrochemical and enzymatic approaches has been addressed. In particular, natural CO2 conversion serves as a model for many processes and extensive studies on microbes and enzymes regarding redox reactions involving CO2 have already been conducted. In this review we focus on the enzymatic conversion of CO2 to carbon monoxide (CO) as the chemical conversion downstream of CO production render CO particularly attractive as a key intermediate. We briefly discuss the different currently known natural autotrophic CO2 fixation pathways, focusing on the reversible reaction of CO2, two electrons and protons to CO and water, catalyzed by carbon monoxide dehydrogenases (CODHs). We then move on to classify the different type of CODHs, involved catalyzed chemical reactions and coupled metabolisms. Finally, we discuss applications of CODH enzymes in photochemical and electrochemical cells to harness CO2 from the environment transforming it into commodity chemicals.

Simple Chemical and Cholinesterase Methods for the Detection of Nerve Agents Using Optical Evaluation

The extreme toxicity of nerve agents and the broad spectrum of their physical and chemical properties, enabling the use of these agents in a variety of tactical situations, is a continuing challenge in maintaining the knowledge and capability to detect them, as well as in finding new effective methods. Despite significant advances in the instrumentation of the analysis of nerve agents, relatively simple methods based on the evaluation of colour signals (absorption and fluorescence), in particular those using the cholinesterase reaction, continue to be of importance. This review provides a brief presentation of the current status of these simple methods, with an emphasis on military applications, and illustrates the high interest of the professional community in their further development. At the same time, it also contains some peculiarities (high reliability and durability, resistance to extreme climatic conditions, work in deployed means of protection, low purchase prices, economic availability especially in a state of war, etc.) that the authors believe research and development of simple methods and means for the detection of nerve agents should respect.

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.

The Relationship Between the Cross-Linker on Chitosan-Coated Magnetic Nanoparticles and the Properties of Immobilized Papain

The immobilized enzymes' properties can be affected by cross-linkers on the surface of supports. To study how cross-linkers alter enzymes function, chitosan-coated magnetic nanoparticles (CMNPs) with immobilized papain were prepared using glutaraldehyde and or genipin, and then, the properties of the nanoparticles and the immobilized enzymes were assessed. The Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), and X-Ray Diffraction (XRD) results showed that the CMNPs were prepared and papain molecules were immobilized on CMNPs by glutaraldehyde (CMNP-Glu-Papain) or by genipin (CMNP-Gen-Papain). Also, the results associated with enzymes activity indicated that the immobilization by glutaraldehyde and genipin increased the pH optimum of papain from 7 to 7.5 and 9, respectively. The kinetic results indicated that the immobilization by genipin slightly affects the enzyme affinity to the substrate. The stability results showed that CMNP-Gen-Papain has more thermal stability than CMNP-Glu-Papain and papain immobilization on CMNPs by genipin leads to stabilization of the enzyme in the presence of polar solvents, probably due to the more hydroxyl groups on CMNPs activated by genipin. In conclusion, this study suggests that there is a relationship between the types of cross-linker on the surface of supports, and the mechanism of action, kinetic parameters, and the stability of immobilized papain.

Preparation of magnetic biochar functionalized by polyvinyl imidazole and palladium nanoparticles for the catalysis of nitroarenes hydrogenation and Sonogashira reaction

Catalysts are essential materials in biotechnology, medicine, industry, and chemistry. On the other hand, recycling and using waste materials is important in economic efficiency and green chemistry. Thus, biochar was prepared from the stem and roots of the Spear Thistle to recover waste. After magnetizing the biochar, its surface was modified with polyvinyl imidazole. Finally, this modified biochar was decorated with Pd nanoparticles and used as a selective and recyclable nanocatalyst in the hydrogenation of nitroarenes and the Sonogashira reaction. The structure of this organic-inorganic nanocatalyst has been characterized by FESEM-EDS, XRD, FT-IR, TEM, and VSM techniques. In the hydrogenation reaction with the amount of 30 mg of nanocatalyst, the temperature of 50 °C in the water solvent, the reaction efficiency reached 99% for 30 min. In addition, under optimal conditions for the Sonogashira reaction: 1.0 mmol iodobenzene, 1.2 mmol phenylacetylene, 20 mg MBC-PVIm/Pd, 2 mmol K2CO3 in H2O at 50 C for 15 min, the reaction efficiency reached 95%. The recyclability of magnetic nanocatalysts was investigated and recognized this nanocatalyst can be used several times without notable loss of its activity.

Immobilization of Lipases on Chitosan Hydrogels Improves Their Stability in the Presence of the Products of Triglyceride Oxidation

A significant bottleneck for the industrial application of lipases stems from their poor stability in the presence of commercial triglycerides. This is mainly due to the inactivating effect of the products of triglyceride oxidation (PTO), which are usually produced when oils and fats, being imported from far countries, are stored for long periods. In this study, the immobilization of a lipase from Candida rugosa on chitosan hydrogels has been carried out following two alternative approaches based on the enzyme adsorption and entrapment to increase the lipase stability under the operating conditions that are typical of oleochemical transformations. The effect of model compounds representing different classes of PTO on a lipase has been studied to optimize the enzyme immobilization method. Particular attention has been devoted to the characterization of the inactivating effect of PTO in nonaqueous media, which are adopted for most industrial applications of lipases.