Activity Of Free Enzyme Research Articles

Affecting parameters on fabrication of β-D-galactosidase immobilized chitosan/poly (vinyl alcohol) electrospun nanofibers

β-galactosidase was successfully immobilized onto chitosan (CS)/polyvinyl alcohol (PVA) blend nanofibers through electrospinning. The effects of both polymer solution parameters and the electrospinning process conditions on the morphology of nanofibers and enzyme activity were studied. FESEM results showed that both morphology and diameter of the nanofibers were significantly influenced by the studied factors. The nanofiber mats obtained from CS/PVA at 50:50 mass ratio and conditions of 20 kV and 0.5 ml/h were selected as the optimized nanofibers, with the smallest diameter and most homogenous structure. On the other hand, catalytic activity of the β-galactosidase -immobilized nanofibers (Enzyme-NF) was not significantly changed with these factors. The catalytic activity of Enzyme-NF was 57.03% of free enzyme activity at pH 6.8 and 4 °C. Furthermore, it showed more temperature stability compared to free β-galactosidase at 50 °C. During 28 days of storage, Enzyme-NF samples retained 77% and 42% of its initial activity in 4 °C and 25 °C, respectively.

Facile Synthesis of S‐Substituted L‐Cysteines with Nano‐sized Immobilized O‐Acetylserine Sulfhydrylase

AbstractMany S‐substituted l‐cysteines are useful pharmaceutical intermediates but require a simple synthesis method. Here we developed enzymatic synthesis of several S‐aryl‐l‐cysteines and S‐benzyl‐l‐cysteine directly from O‐acetylserine (OAS) with immobilized O‐acetylserine sulfhydrylase CysM. Novel iron‐oxide magnetic nanoparticles (MNPs) with cobalt‐nitrilotriacetic acid function were prepared with a diameter of 80 nm in 75 % yield. Direct immobilization of His‐tagged CysM in the cell‐free extract on the MNPs via affinity attachment afforded stable nanobiocatalyst with 97 % enzyme loading efficiency and 93 % free enzyme activity. The immobilized enzyme catalyzed the biotransformation of benzylthiol and OAS to give S‐benzyl‐l‐cysteine in 88 % yield. The nanobiocatalyst also demonstrated high recyclability, retaining 95 % productivity in the fifth cycle. The immobilized CysM accepts various arylthiols to react with OAS, giving rise to a new synthesis route of several S‐substituted l‐cysteines in 60–96 % yield.

Titania/lignin hybrid materials as a novel support for α-amylase immobilization: A comprehensive study

α-Amylase from Aspergillus oryzae was immobilized via covalent bonds and by physical interactions on a synthesized titania/lignin novel hybrid support. A temperature of 5°C, a pH of 7.0, an initial enzyme solution concentration of 3.0mg/mL and a 3h process duration were found to be optimal for the highest activity of the immobilized enzyme. Moreover, the effect of temperature, pH, storage time and repeated catalytic cycles on the activity of free and immobilized enzyme was examined. Bound α–amylase showed enhanced thermal and chemical stability, and its reusability was also improved. Immobilized α-amylase retained over 80% of its initial activity when stored for 30days at 4°C. Kinetic parameters of the free and immobilized biocatalyst were calculated and compared. The maximum reaction rate (Vmax) and turnover number (kcat) were slightly lower for the immobilized enzyme than for the free enzyme. It should be clearly stated that this work presents a useful protocol to produce stable and active immobilized α–amylase onto titania/lignin hybrid which may also be applied to immobilization of other enzymes.

Endothelial nitric oxide synthase oxygenase on lipid nanodiscs: A nano-assembly reflecting native-like function of eNOS

Endothelial nitric oxide synthase (eNOS) is a membrane-anchored enzyme. To highlight the potential role and effect of membrane phospholipids on the structure and activity of eNOS, we have incorporated the recombinant oxygenase subunit of eNOS into lipid nanodiscs. Two different size distribution modes were detected by multi-angle dynamic light scattering both for empty nanodiscs, and nanodiscs-bound eNOSoxy. The calculated hydrodynamic diameter for mode 1 species was 9.0 nm for empty nanodiscs and 9.8 nm for nanodisc bound eNOSoxy. Spectroscopic Griess assay was used to measure the enzymatic activity. Remarkably, the specific activity of nanodisc-bound eNOSoxy is ∼65% lower than the activity of free enzyme. The data shows that the nano-membrane environment affects the catalytic properties of eNOS heme domain.

Cellulose monoacetate/polycaprolactone and cellulose monoacetate/polycaprolactam blended nanofibers for protease immobilization

ABSTRACTEnzymes can be used multiple times when they are immobilized on a support. More enzymes can be immobilized on a surface when nanofibers are used as a supporting surface because the specific surface area increases tremendously. In this regard, polycaprolactam/cellulose monoacetate (PA6/CMA) and polycaprolactone/cellulose monoacetate (PCL/CMA) blended nanofibers (NFs) were prepared via an electrospinning process. Protease enzymes were immobilized on neat PA6, PCL, PA6/CMA, and PCL/CMA nanofibers and glutaraldehyde (GA) activated analogs through the physical adsorption method. The immobilized enzyme activity was measured by using a casein substrate, and the results were compared with free enzyme activity. Among all of the samples, the highest immobilization yield of about 82% was obtained with GA‐activated neat PCL NF samples. The best remaining activity of the immobilized enzymes on pure CMA NFs was found to be 59% after seven reuses. Even after nine reuses, enzyme activities are still observed on the CMA NF samples. It was expected that the addition of CMA in PCL and PA6 NFs would increase the reusability number to reach the reusability of CMA NFs, but it was not significantly enhanced. If CMA chains could be mostly collected on the sheath or close to the sheath of the NFs during the electrospinnig process, this target could be achieved. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45479.

Immobilization of Cellulase Enzyme on Zinc Ferrite Nanoparticles in Increasing Enzymatic Hydrolysis on Ultrasound-Assisted Alkaline Pretreated Crotalaria Juncea Biomass

Objectives: To synthesize ferrite nano particles; to measure size of the particles by FTIR and XRD studies and enzyme saccharification on ultra sound assisted alkaline pretreated biomass using free and immobilized enzyme. Methods/ Statistical Analysis: In the present work, Zinc ferrite particles were synthesized using co-precipitation method. Cellulase enzymes were immobilized on covalently activated ferrite nanoparticles via glutaraldehyde as a crosslinker. Biochemical characterization of free and immobilized enzyme activity were performed on CMC as a substrate. The efficiency of immobilized enzyme was evaluated based on its binding efficiency on the nanoparticles, thermostability, and reusability. Enzymatic hydrolysis was performed on ultrasound-assisted alkaline pretreated sunn hemp biomass using free and immobilized enzymes. Findings: Around 74% of binding was achieved at 4mg/ml of ferrite loading to enzyme concentration of 20 units. Comparative study on effects of pH and temperature was done on both free and immobilized enzyme and it was observed that the immobilized enzyme has maximum activity at pH 5 and temperature 60˚C. Also, the immobilized enzyme was stable at 60˚C while retaining its activity up to 3 recycles. The immobilized enzyme showed 53% hydrolysis yield on pretreated sunn hemp biomass. Application/Improvements: The research on the interaction between zinc ferrite and cellulase in immobilization and also the recovery of enzymes can determine an efficient approach for bioethanol production in industrial scale. The lab scale can be scaled-up to use at pilot and industrial scales.

Over-expression of a C3H-type zinc finger gene contributes to salt stress tolerance in transgenic broccoli plants

C3H-type zinc finger proteins play important roles in plant growth, development, and stress responses. A C3H-type zinc finger gene, designated BoC3H, was isolated from broccoli (Brassica oleracea var. italica). The complete coding sequence of BoC3H was 1074 bp in length, encoding 357 amino acids with two CCCH motifs of C-X7-C-X5-C-X3-H and C-X5-C-X4-C-X3-H. The transcripts of BoC3H were profoundly induced by NaCl, and the highest expression level was observed at 18 h after treatment. Four broccoli lines over-expressing the BoC3H gene were obtained, and they exhibited higher germination rates, dry weight and chlorophyll content in response to salt stress as compared to those of wild type plants. Over-expression of BoC3H significantly decreased hydrogen peroxide (H2O2) level, relative electrical conductivity (REC) and malondialdehyde (MDA) contents, but dramatically increased free proline content, catalase, peroxidase and superoxide dismutase enzyme activities, resulting in less cell death in the leaves of transgenic plants. Taken together, our results suggest that BoC3H is likely to contribute to salt stress tolerance by regulating H2O2, REC, free proline, MDA and antioxidant enzyme levels in broccoli.

ALTERATION IN CARBOHYDRATE METABOLISM BY SUB-ACUTE LEAD EXPOSURE: A DOSE-DEPENDENT STUDY

Objective: The study was conducted to evaluate the dose-dependent effects of sub-acute lead exposure on certain aspects of carbohydrate metabolism.Methods: Swiss albino male mice (weighing 30-35 g) were selected for the present study and divided into five groups; one control group and others lead-treated groups i.e. Group A (5 mg/kg body weight), Group B (10 mg/kg body weight), Group C (15 mg/kg body weight) and Group D (20 mg/kg body weight). Parameters like blood and liver glucose, glycogen and pyruvic acid contents were determined in liver tissue. The enzyme activities like pyruvate dehydrogenase, malate dehydrogenase and glucose 6-phosphatase were recorded in that tissue. Additionally, free amino acid nitrogen content and transaminase enzyme activities were also evaluated in liver tissue of mice.Results: The study reveals that lead caused a significant diminution of blood and hepatic glucose levels and fall in liver glycogen content in a dose-dependent manner, the highest effect was observed in animals treated with lead at a dose of 20 mg/kg body weight. Glucose 6-phosphatase activity was decreased significantly in all the treated groups. There was a dose-dependent increase in pyruvic acid content whereas pyruvate dehydrogenase, malate dehydrogenase and transaminase enzyme activities were significantly depressed in a dose-dependent fashion in all the treated animals. Additionally, lead treatment significantly (p<0.001) enhanced free amino acid nitrogen in the liver to provide a substrate for gluconeogenesis.Conclusion: It is suggested that an adaptive mechanism is initiated by stimulating and retarding glycogenolytic and glycolytic activity and also by rising in the content of free amino acid nitrogen to recover from the lead stressed toxic manifestation

Cellulase cross-linked enzyme aggregates (CLEA) activities can be modulated and enhanced by precipitant selection

BACKGROUND: Crosslinked enzyme aggregates (CLEA) technology is a rapid and versatile method to produce immobilized enzymes via precipitation and cross-linking. A direct relationship between CLEA final activity and process parameters is however yet to be clarified. To address the issue, we have used a factorial design to test the formation and optimization of CLEA made from technical grade cellulase (EC 3.2.1.4). Three types of precipitant (ammonium sulfate, polyethylene glycol, tert-butyl alcohol) were used at varied levels of cross-linker concentration, cross-linking time, and temperature. RESULTS: It was found that the CLEAs produced with tert-butyl alcohol were inactive, whereas the polyethylene glycol- and ammonium sulfate-CLEA, recovered 29 and 17% of the free enzyme activity, respectively. Testing for re-usability, we observed that the polyethylene glycol-CLEA maintained 40% of the initial activity after four cycles, in contrast the ammonium sulfate-CLEA only maintained 10% of its activity after one cycle. CONCLUSION: Our study highlights the importance of evaluating the effect of the precipitant on final CLEA activity rather than re-solubilized enzyme activity. It was demonstrated that polyethylene glycol, despite not being able to precipitate the enzymes as readily as ammonium sulfate, resulted in better performing CLEA. (Less)

A comprehensive review of biodiesel production methods from various feedstocks

ABSTRACTThis article reviews the performance of biodiesel production from various feedstocks and analyzes the associated challenges. The existing literature survey dealt with the potential and important feedstocks like edible oil, non-edible oil, animal fat and algae oil for the biodiesel production. The result shows that the various sources have different yield due to processes variables. The yield of biodiesel differs with the feedstocks due to physico-chemical properties of sources and the process variables. In order to increase the biodiesel yield, the novel technologies are warranted in the bioenergy research field. Recent research focuses on the cheap, abundant feedstocks, novel production and purification technologies for biodiesel. Transesterification by enzyme has advantageous in view of conversion, yield and reusability whereas low yield of chemical catalyst catalyzed transesterification reactions in recent years. Lipase mediated transesterification has increased the rate of reaction followed by high conversion. But the activity of free enzyme is reduced as stability is low. In order to overcome this drawback, the immobilized lipase mediated transesterification methodology has been introduced in recent studies. Nanobiocatalyst focuses exclusively on the transesterification of oils using methanol to produce fatty acid methyl esters (FAME). Importantly, the lipase binds on magnetic particles with various size ranges, confirming stability and giving more reactive centers. Analytical methods such Fourier transform infrared spectra and transmission electron microscopy are used to characterize the structure of nanoparticles which exhibit better resistance to temperature and pH, stirring speed, enzyme loading, viscosity of oil and alcohol/oil molar ratio and free fatty acid. For the analysis of FAME, Gas Chromatography – Mass Spectroscopy (GC-MS) was extensively used. Nowadays microwave and ultrasound assisted transesterification techniques increases the conversion rate of oils into biodiesel. These methods may require less energy, compared to the conventional method. This method may require less energy, compared to the conventional method. In addition, the statistical (response surface methodology) and stochastical (artificial neural network and genetic algorithm) optimization techniques are expected to provide the best process response to the highest acid conversion and efficiency.

Encapsulation of amine dehydrogenase in hybrid titania nanoparticles by polyethylenimine coating and templated biomineralization

Asymmetric synthesis of chiral amines by amine dehydrogenases (AmDH), which catalyzed reductive amination of ketones with high enantioselectivity, is an ideal route for production of chiral amine. In this study, a facile approach is proposed to immobilize unstable amine dehydrogenase by two steps. Firstly, polyethylenimine (PEI), a cationic polymer, was applied for coating enzyme to inhibit the dissociation of multimeric enzymes. Strong interaction of PEI with AmDH were analyzed and indicated PEI provided the hydrophilic microenvironment for enzyme. The half-life was improved about 18 fold in 50°C. Secondly, to further stabilize AmDH-PEI, PEI coated on AmDH surface was used as a biological template inducing the hydrolysis and condensation of titanium precursor to form titania. AmDH-PEI-Ti possessed more than 80% of the catalytic activity of free enzyme and the entrapment efficiency can be high up to 90%. A mechanistic illustration of the formation of AmDH-PEI-Ti nanoparticles were proposed. Titania provided a rigid cage pocket for the protection from structure unfolding. This generally applicable strategy offers a potential technique for multimeric enzyme immobilization with the advantages of low cost, easy operation, high reservation of activity and high stability.

Production of Extracellular Anti-leukemic Enzyme L-asparaginase from Fusarium solani AUMC 8615 Grown under Solid-State Fermentation conditions: Purification and Characterization of The Free and Immobilized Enzyme

AUMC 8615 was selected as the most potent fungal strain for the enzyme production under solid state fermentation (SSF) using agro-industrial residues. Wheat bran supported maximum enzyme production followed by rice bran and corn cob. The optimum conditions for maximum production of L-asparaginase under SSF occurred on the fifth day of incubation at 30°C, pH 8.0, 60% of initial moisture content and supplementation with 0.2% (w/v) glucose and 0.5% (w/v) ammonium sulphate. L-asparaginase was purified to homogeneity by ammonium sulphate precipitation, gel filtration and ion exchange chromatography giving 299.58 purification fold. SDS-PAGE showed that the purified enzyme consists of two subunits of molecular weights 70 and 80 kDa, respectively. The enzyme was efficiently immobilized by covalent binding with activated charcoal giving an immobilization yield of 80.40%. Optimum pH values were 9.0 and 8.0 for free and immobilized enzyme, respectively. While, Optimum reaction temperatures were 37°C and 45°C for free and immobilized enzyme, respectively. After incubation for 2 hr at 37°C, the relative activity of free enzyme decreases to 35% whereas for the immobilized enzyme decreased only to 57% at 45°C.

Electrospun polyvinyl alcohol/bovine serum albumin biocomposite membranes for horseradish peroxidase immobilization

Electrospinning, a simple and versatile method to fabricate nanofibrous supports, has attracted attention in the field of enzyme immobilization. Biocomposite nanofibers were fabricated from mixed PVA/BSA solution and the effects of glutaraldehyde treatment, initial BSA concentration and PVA concentration on protein loading were investigated. Glutaraldehyde cross-linking significantly decreased protein release from nanofibers and BSA loading reached as high as 27.3% (w/w). In comparison with the HRP immobilized into the nascent nanofibrous membrane, a significant increase was observed in the activity retention of the enzyme immobilized into the PVA/BSA biocomposite nanofibers. The immobilized HRP was able to tolerate much higher concentrations of hydrogen peroxide than the free enzyme and thus the immobilized enzyme did not demonstrate substrate inhibition. The immobilized HRP retained∼50% of the free enzyme activity at 6.4mM hydrogen peroxide and no significant variation was observed in the KM value of the enzyme for hydrogen peroxide after immobilization. In addition, reusability tests showed that the residual activity of the immobilized HRP were 73% after 11 reuse cycles. Together, these results demonstrate efficient immobilization of HRP into electrospun PVA/BSA biocomposite nanofibers and provide a promising immobilization strategy for biotechnological applications.

Laccase encapsulation in chitosan nanoparticles enhances the protein stability against microbial degradation.

A novel concept with the result of enzyme stabilization against microbial degradation in real bioremediation processes was developed through the encapsulation of laccase in chitosan nanoparticles. Besides of abundant information on laccase-chitosan conjugates, we report the laccase encapsulation into nanoparticles based in chitosan. The chitosan-tripolyphosphate technique was applied for the production of morphologically homogeneous enzymatic nanoparticles, with high enzyme encapsulation efficiency, small asymmetric sizes (from 40 to 90nm), and rough surfaces. Contrary to macroscopic immobilized enzymes, temperature and pH activity profiles of nano-sized laccase were similar to those of free enzyme. The substrate affinity constant (K M) of nano-encapsulated laccase was similar to these from free enzyme, while its activity rate constant (k cat) represented 60% of these obtained with free enzyme. Importantly, stability of nano-encapsulated laccase against microbial degradation in soil, compost, and wastewater was significantly increased. After 24h exposure to wastewater from a treatment plant, the laccase activity of the nanoparticles was 82.8% of initial activity, compared with only 7.8% retained activity for free enzyme. After 36h incubation in compost extract, the laccase nanoparticles showed 72.4% of the initial activity, while the free enzyme was almost completely inactivated. Finally, after 84h incubation in soil extract, the nanoparticles and free preparations showed 57.9 and 17.3% of the initial activity, respectively. Thus, the nanoencapsulation of enzymes able to transform pollutants is an alternative to improve the operational lifetime of enzymes in real environmental applications.

Lysosome-related organelles extracts from egg-white for hypermelanosis reduction

Pigmentary disorders generally indicate that an increased amount of melanin, leading to darker color of skin, called hypermelanosis. Thus, several methods were studied for finding therapy of hypermelanosis until now in worldwide. In this study, the hypermelanosis reduction has been observed with daily lysosome-related organelles (LRO) extract from eggwhite. The scrub was used for enzyme extraction so as to maintain the stability of the extracted enzyme. The LRO extracts were divided and into two groups: free enzyme and fresh enzyme. Free enzyme was extracted on the first day from the LRO and fresh enzyme was extracted by scrub from LRO daily. The melanin dissolved phosphate buffer (pH 7.0) was treated by two groups of enzymes for a period of 30 days. The fresh enzymes were found to be more effective than the free enzymes. The activity of free enzymes decreases with time and as a result it could not degrade melanin after 36 days. The peroxidase activity was also measured and it matched with the results of previous studies. Therefore, the daily fresh enzymes displayed remarkable ability in hypermelanosis reduction than with free enzyme that lost its activity after some time. The present work can be potentially used for dermal disease in medical industry and also in cosmetic products.

Tyrosinase immobilized on a hydrophobic membrane.

Polyvinylidene fluoride (PVDF) membrane surfaces were ad hoc functionalized chemically to make them suitable for enzymatic immobilization. The process was performed by grafting the membrane surface with 1,4-diaminobutane and subsequently by activating it with glutarhaldehyde. The chemico-physical properties of the original PVDF membrane and of the modified membranes were studied by infrared spectroscopy, scanning electron microscopy, and static contact angle measurements. The activated membranes were used as a support for covalent immobilization of tyrosinase. The activity of free and immobilized enzyme was studied and compared. The experimental data showing the specific activity of the immobilized enzyme are similar to the value obtained with the free one. This means that the immobilization procedure did not alter the catalytic properties of the tyrosinase. In addition, the surface modification of the PVDF made it a promising material to use in enzyme or biomolecule immobilization processes.

Characteristic features and dye degrading capability of agar⿿agar gel immobilized manganese peroxidase

Immobilization of enzymes has been regarded as an efficient approach to develop biocatalyst with improved activity and stability characteristics under reaction conditions. In the present study, purified manganese peroxidase (MnP) from Ganoderma lucidum IBL-05 was immobilized in agar⿿agar support using entrapment technique. Maximum immobilization yield was accomplished at 4.0% agar⿿agar gel. The immobilized MnP exhibited better resistance to changes in pH and temperature than the free enzyme, with optimal conditions being pH 6.0 and 50°C. The kinetic parameters Km and Kcat/Km for free and entrapped MnP were calculated to be 65.6mM and 6.99M⿿1s⿿1, and 82mM and 8.15M⿿1s⿿1, respectively. Thermo-stability was significantly improved after immobilization. After 120h, the insolubilized MnP retained its activity up to 71.9% and 60.3% at 30°C and 40°C, respectively. It showed activity until 10th cycle and retained 74.3% residual activity after 3th cycle. The effects of H2O2, ionic strength and potential inhibitors on activity of free and immobilized enzyme were investigated. Moreover, the decolorization of three structurally different dyes was monitored in order to assess the degrading capability of the entrapped MnP. The decolorization efficiencies for all the tested dyes were 78.6⿿84.7% after 12h. The studies concluded that the toxicity of dyes aqueous solutions was significantly reduced after treatment. The remarkable catalytic, thermo-stability and re-cycling features of the agar⿿agar immobilized MnP display a high potential for biotechnological applications.

Enhancement of Alkaline Protease Activity and Stability via Covalent Immobilization onto Hollow Core-Mesoporous Shell Silica Nanospheres.

The stability and reusability of soluble enzymes are of major concerns, which limit their industrial applications. Herein, alkaline protease from Bacillus sp. NPST-AK15 was immobilized onto hollow core-mesoporous shell silica (HCMSS) nanospheres. Subsequently, the properties of immobilized proteases were evaluated. Non-, ethane- and amino-functionalized HCMSS nanospheres were synthesized and characterized. NPST-AK15 was immobilized onto the synthesized nano-supports by physical and covalent immobilization approaches. However, protease immobilization by covalent attachment onto the activated HCMSS–NH2 nanospheres showed highest immobilization yield (75.6%) and loading capacity (88.1 μg protein/mg carrier) and was applied in the further studies. In comparison to free enzyme, the covalently immobilized protease exhibited a slight shift in the optimal pH from 10.5 to 11.0, respectively. The optimum temperature for catalytic activity of both free and immobilized enzyme was seen at 60 °C. However, while the free enzyme was completely inactivated when treated at 60 °C for 1 h the immobilized enzyme still retained 63.6% of its initial activity. The immobilized protease showed higher Vmax, kcat and kcat/Km, than soluble enzyme by 1.6-, 1.6- and 2.4-fold, respectively. In addition, the immobilized protease affinity to the substrate increased by about 1.5-fold. Furthermore, the enzyme stability in various organic solvents was significantly enhanced upon immobilization. Interestingly, the immobilized enzyme exhibited much higher stability in several commercial detergents including OMO, Tide, Ariel, Bonux and Xra by up to 5.2-fold. Finally, the immobilized protease maintained significant catalytic efficiency for twelve consecutive reaction cycles. These results suggest the effectiveness of the developed nanobiocatalyst as a candidate for detergent formulation and peptide synthesis in non-aqueous media.

Nanobiocatalysis: Nanostructured materials – a minireview

AbstractThe field of nanobiocatalysis has experienced a rapid growth due to recent advances in nanotechnology. However, biocatalytic processes are often limited by the lack of stability of the enzymes and their short lifetime. Therefore, immobilization is key to the successful implementation of industrial processes based on enzymes. Immobilization of enzymes on functionalized nanostructured materials could give higher stability to nanobiocatalysts while maintaining free enzyme activity and easy recyclability under various conditions. This review will discuss recent developments in nanobiocatalysis to improve the stability of the enzyme using various nanostructured materials such as mesoporous materials, nanofibers, nanoparticles, nanotubes, and individual nanoparticles enzymes. Also, this review summarizes the recent evolution of nanostructured biocatalysts with an emphasis on those formed with polymers. Based on the synthetic procedures used, established methods fall into two important categories: “grafting onto” and “grafting from”. The fundamentals of each method in enhancing enzyme stability and the use of these new nanobiocatalysts as tools for different applications in different areas are discussed.

Immobilization of O-acetylserine sulfhydrylase as a highly active and recyclable nanobiocatalyst: efficient synthesis of β-pyrazol-1-yl-l-alanine

O-Acetylserine sulfhydrylase (OASS) is immobilized directly from CFE containing His-tagged OASS with magnetic nanoparticles Ni-NTA-MNPsviaaffinity attachment. The immobilized enzyme shows full free-enzyme activity and excellent recyclability and produces 1080 mM β-pyrazol-1-yl-alanine in 20 reaction cycles.