Zinc sulfide-chitosan hybrid nanoparticles as a robust surface for immobilization of Sillago sihama α-amylase

In-situ co-immobilization of lipase, lipoxygenase and L-cysteine within a metal-amino acid framework for conversion of soybean oil into higher-value products

We propose a co-immobilized chemo-enzyme cascade system to mitigate random intermediate diffusion from the mixture of individual immobilized catalysts and achieve a one-pot reaction of multi-enzyme and reductant. Catalyzed by lipase and lipoxygenase, unsaturated lipid hydroperoxides (HPOs) were synthesized. 13(S)-hydroperoxy-9Z, 11E-octadecadienoic acid (13-HPODE), one compound of HPOs, was subsequently reduced to 13(S)-hydroxy-9Z, 11E-octadecadienoic acid (13-HODE) by cysteine. Upon the optimized conditions, 75.28 mg of 13-HPODE and 4.01 mg of 13-HODE were produced from per milliliter of oil. The co-immobilized catalysts exhibited improved yield compared to the mixture of individually immobilized catalysts. Moreover, it demonstrated satisfactory durability and recyclability, maintaining a relative HPOs yield of 78.5% after 5 cycles. This work has achieved the co-immobilization of lipase, lipoxygenase and the reductant cysteine for the first time, successfully applying it to the conversion of soybean oil into 13-HODE. It offers a technological platform for transforming various oils into high-value products.

Activation of Inert Supports for Enzyme(s) Immobilization Harnessing Biocatalytic Sustainability for Perennial Utilization

Although Nature's evolution and intelligence have gifted humankind with noteworthy enzyme candidates to simplify complex reactions with ultrafast, overselective, effortless, mild biological reactions for millions of years, their availability at minute-scale, short-range time-temperature stability, and purification costs hardly justify recycling/or reuse. Covalent immobilization, particularly via multipoint bonds, prevents denaturing, maintains activities for long-range time, pH, and temperature, and makes catalysts available for repetitive usages; which attracts researchers and industries to bring more immobilized enzyme contenders in science and commercial progressions. Inert-support activation, the most crucial step, needs appropriate activators; under mild conditions, the activator's functional group(s) still present on the activated support rapidly couples the enzyme, preventing unfolding and keeping the active site alive. This review summarizes exciting experimental advances, from the 1950s until today, in the activation strategies of various inert supports with five different surface activators, the cyanogen bromide, the isocyanate/isothiocyanate, the glutaraldehyde, the carbodiimide (with or without N-hydroxysuccinimide (NHS)), and the diazo group, for the immobilization of diverse enzymes for broader applications. These activators under mild pH (7.5 ± 0.5) and temperature (27 ± 3 °C) and ordinary stirring witnessed support activation and enzyme coupling and put off unfolding, harnessing addressable activities (CNBr: 40 ± 10%; -N═C═O/-N═C═S: 32 ± 7%; GA: 70 ± 15%; CDI: 60 ± 10%; -N+≡N: 80 ± 15%), while underprivileged stability, longevity, and reusabilities keep future investigations alive.

Site-directed display of zearalenone lactonase on spilt-intein functionalized nanocarrier for green and efficient detoxification of zearalenone

In this study, we prepared a functional organic-inorganic hybrid nanoflower (InHNF) via split intein moiety in a biomineralization process without using organic solvents. InHNF could specifically bind the target enzymes from crude cell lysates within seconds and site-directedly display them on the surface by forming a peptide bond with enzyme's terminal amino acid residue. This unique feature enabled InHNF to increase the specific activity of zearalenone detoxifying enzyme ZHD518 by 40 ∼ 60% at all tested temperatures and prevented enzyme denaturation even under extreme pH conditions (pH 3-11). Furthermore, it exhibited excellent operational stability, with a residual activity of over 70% after eight reaction cycles. Strikingly, InHNF-ZHD518 achieved above 50% ZEN degradation despite the near inactivation of free ZHD518 in beer sample. Overall, InHNF nanocarriers can achieve environmentally friendly, purification-free, and site-directed immobilization of food enzymes and enhance their catalytic properties, making them suitable for a wide range of industrial applications.

Hydrolysis of Casein by Pepsin Immobilized on Heterofunctional Supports to Produce Antioxidant Peptides

A study was carried out on the immobilization of pepsin in activated carbon functionalized by different techniques (glutaraldehyde, genipin, and metallization) aiming at its application in obtaining bioactive peptides through casein hydrolysis. Studies of the immobilized derivatives were carried out in addition to the evaluation of the antioxidant potential of the peptides. Among the pH range studied, pH 3.0 was selected due to the higher activity of the derivatives at this pH. The support modification by metallization was the method with the best results, providing a 121% increase in enzymatic activity compared to other immobilization methods. In addition, this derivative provided activity closer to the soluble enzyme activity (3.30 U) and better storage stability, and allows reuse for more than 8 cycles. In turn, the peptides from casein hydrolysis showed potential as antioxidant agents, with a DPPH radical scavenging activity higher than 70%, maximum protection against β-carotene oxidation close to 70%, and a maximum reducing power of Fe(III) into Fe(II) of 400 uM by the FRAP assay. The results showed that the new techniques for modification of activated carbon can be a promising approach for pepsin immobilization.

Perspective on Agricultural Industrialization: Modification Strategies for Enhancing the Catalytic Capacity of Keratinase

Keratinases is a special hydrolytic enzyme produced by microorganisms, which has the ability to catalyze the degradation of keratin. Currently, keratinases show great potential for application in many agricultural and industrial fields, such as biofermented feed, leather tanning, hair removal, and fertilizer production. However, these potentials have not yet been fully unleashed on an industrial scale. This paper reviews the sources, properties, and catalytic mechanisms of keratinases. Strategies for the molecular modification of keratinases are summarized and discussed in terms of improving the substrate specificity, thermostability, and pH tolerance of keratinases. The modification strategies are also enriched by the introduction of immobilized enzymes and directed evolution. In addition, the selection of modification strategies when facing specific industrial applications is discussed and prospects are provided. We believe that this review serves as a reference for the future quest to extend the application of keratinases from the laboratory to industry.

Chitin Deacetylase from Bacillus aryabhattai TCI-16: Heterologous Expression, Characterization, and Deacetylation Performance

Chitin deacetylase (CDA) removes the acetyl group from the chitin molecule to generate chitosan in a uniform, high-quality deacetylation pattern. Herein, BaCDA was a novel CDA discovered from our previously isolated Bacillus aryabhattai strain TCI-16, which was excavated from mangrove soil. The gene BaCDA was cloned and overexpressed in Escherichia coli BL21 (DE3) to facilitate its subsequent purification. The purified recombinant protein BaCDA was obtained at a concentration of about 1.2 mg/mL after Ni2+ affinity chromatography. The molecular weight of BaCDA was around 28 kDa according to the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. In addition, BaCDA exhibited a significant deacetylation effect on colloidal chitin, and the deacetylation degree was measured from the initial 25.69 to 69.23% by Fourier transform infrared (FT-IR) spectroscopy. Scanning electron microscopy (SEM) observation showed that the surface of colloidal chitin after enzymatic digestion was rough, the crystal fibers disappeared, and the chitin structure was loose and porous with grooves. The results of electrospray ionization mass spectrometry (ESI-MS) showed that BaCDA had full-deacetylation activity against (GlcNAc)4. Molecular docking revealed that BaCDA had an open active pocket capable of binding to the GlcNAc unit. This study not only provides a novel enzymatic resource for the green and efficient application of chitin but also helps to deepen the understanding of the catalytic mechanism of CDA.

A newly synthesized magnetic nanoparticle coated with glycidyl methacrylate monomer and 1,2,4-Triazole: Immobilization of α-Amylase from Bacillus licheniformis for more reuse, stability, and activity in the presence of H2O2

α-Amylase is a secretory enzyme commonly found in nature. The α-Amylase enzyme catalyzes the hydrolysis of α-D-(1,4)-glucosidic bonds in starch, glycogen, and polysaccharides. The chemical characterization of the composite carrier and the immobilized enzyme was performed, and the accuracy of the immobilization was confirmed by FTIR, SEM, and EDS analyses. The X-ray diffraction (XRD) analysis indicates that the magnetic nanoparticle retained its magnetic properties following the modification process. Based on the Thermogravimetric Analysis (TGA) outcomes, it was evident that the structural integrity of the FPT nanocomposite remained unchanged at 200°C. The optimal pH was determined to be 5.5, and no alteration was observed following the immobilization process. Purified α-amylases usually lose their activity rapidly above 50°C. In this study, Bacillus licheniformis α-Amylase enzyme was covalently immobilized on the newly synthesized magnetic composite carrier having more azole functional group. For novelty-designed immobilized enzymes, while there is no change in the pH and optimum operating temperature of the enzyme with immobilization, two essential advantages are provided to reduce enzyme costs: the storage stability and reusability are increased. Furthermore, our immobilization technique enhanced enzyme stability when comparing our immobilized enzyme with the reference enzyme in industrial applications. The activity of the immobilized enzyme was higher in presence of 1-3% H2O2.

Dissecting dual specificity: Identifying key residues in L-asparaginase for enhanced acute lymphoid leukemia therapy and reduced adverse effects

L-asparaginase from Escherichia coli (EcA) has been used for the treatment of acute lymphoid leukemia (ALL) since the 1970s. Nevertheless, the enzyme has a second specificity that results in glutaminase breakdown, resulting in depletion from the patient's body, causing severe adverse effects. Despite the huge interest in the use of this enzyme, the exact process of glutamine depletion is still unknown and there is no consensus regarding L-asparagine hydrolysis. Here, we investigate the role of T12, Y25, and T89 in asparaginase and glutaminase activities. We obtained individual clones containing mutations in the T12, Y25 or T89 residues. After the recombinant production of wild-type and mutated EcA, The purified samples were subjected to structural analysis using Nano Differential Scanning Fluorimetry, which revealed that all samples contained thermostable molecules in their active structural conformation, the homotetramer conformation. The quaternary conformation was confirmed by DLS and SEC. The activity enzymatic assay combined with molecular dynamics simulation identified the contribution of T12, Y25, and T89 residues in EcA glutaminase and asparaginase activities. Our results mapped the enzymatic behavior paving the way for the designing of improved EcA enzymes, which is important in the treatment of ALL.

Mechanical properties and water resistance improvement of thermoplastic modified starch, carboxymethyl cellulose, and zinc oxide nanometal particles by reactive blending

Novel biodegradable thermoplastic starch (TPS) with high mechanical properties and water resistance was developed using reactive blending technique. Effect of zinc oxide (ZnO) addition to TPS properties and reaction was investigated. Thermoplastic modified starch (TPMS) was prepared by melt-mixing modified starch with glycerol 70/30%wt/wt. Carboxy methyl cellulose (CMC) 5%wt was incorporated with modified starch, glycerol, and zinc oxide (ZnO) 0-5 %wt. Fourier-transform infrared (FTIR) spectroscopy analysis confirmed the formation of the carboxyl anion (OZn) between the -COO- of CMC and the free Zn+ ion of ZnO. The tensile strength of the TPMS/CMC/ZnO blend increased 7 time with ZnO 5 % (14 MPa) addition compared to TPMS (2 MPa). The color (∆E) of TPMS/CMC/ZnO differed notably at high ZnO concentrations (1-5 %wt). The TPMS/CMC blend displayed a smooth fracture surface due to the miscibility of the materials. Small particles of ZnO dispersed finely in the TPMS matrix and increased the interfacial tension and water contact angle of the blends. The miscibility of TPS with CMC and the occurrence of ionic interactions of -COO- of CMC and -OH of starch with the Zn+ ion as physical crosslinking were indicated to improve the mechanical properties and water resistance of the blends.

Three anthocyanin-rich berry extracts regulate the in vitro digestibility of corn starch: Physicochemical properties, structure and α-amylase

This study aimed to compare the regulatory effects of blue honeysuckle anthocyanins (BHA), blueberry anthocyanins (BBA), and blackcurrant anthocyanins (BCA) on the in vitro digestibility of corn starch in terms of starch physicochemical properties and structure, as well as α-amylase inhibition. The results revealed that adding all three anthocyanins lowered digestibility in the following order: BHA > BCA > BBA. The terminal digestibility (C∞) decreased from 73.84 % to 57.3 % with the addition of 10 % BHA, while the resistant starch (RS) content increased from 4.39 % to 48.82 %. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis indicated that anthocyanins and starch interacted through noncovalent bonds. Differential scanning calorimetry (DSC) analysis showed that the gelatinization enthalpy was dramatically lowered in all three anthocyanin groups, with 10 % BHA producing a 38.58 % drop. Rheological property analysis showed that anthocyanins increased the apparent viscosity and modulus with starch. The interaction between anthocyanin and α-amylase was mainly through the formation of hydrogen bonds and hydrophobic forces. This research provides theoretical guidance for developing low glycemic index (GI) anthocyanin starch-based foods.

Rational design of biocatalysts based on covalent immobilization of acylase enzymes

Acylases catalyze the hydrolysis of amide bonds. Penicillin G acylase (PGA) is used for the semi-synthesis of penicillins and cephalosporins. Although protein immobilization increases enzyme stability, the design of immobilized systems is difficult and usually it is empirically performed. We describe a novel application of our strategy for the Rational Design of Immobilized Derivatives (RDID) to produce optimized acylase-based immobilized biocatalysts for enzymatic bioconversion. We studied the covalent immobilization of the porcine kidney aminoacylase-1 onto aldehyde-based supports. Predictions of the RDID1.0 software and the experimental results led to the selection of glyoxyl-Sepharose CL 4B support and pH 10.0. One of the predicted clusters of reactive amino groups generates an enzyme-support configuration with highly accessible active sites, contributing with 82% of the biocatalyst's total activity. For Escherichia coli PGA, the predictions and experimental results show similar maximal amounts of immobilized protein and activity at pH 8.0 and 10.0 on glyoxyl-Sepharose CL 10B. However, thermal stability of the immobilized derivative is higher at pH 10.0 due to an elevated probability of multipoint covalent attachment. In this case, two clusters of amino groups are predicted to be relevant for PGA immobilization in catalytically competent configurations at pH 10.0, showing accessible active sites and contributing with 36% and 44% of the total activity, respectively. Our results support the usefulness of the RDID strategy to model different protein engineering approaches (site-directed mutagenesis or obtainment of fusion proteins) and select the most promising ones, saving time and laboratory work, since the in silico-designed modified proteins could have higher probabilities of success on bioconversion processes.

Analytical expression for the model that describes the heterogeneous reaction-diffusion process with immobilized enzyme (penicillin G acylase)

This research article examines the reaction-diffusion process in an immobilized enzyme batch reactor. The model incorporates strongly non-linear factors that are associated with standard Michaelis-Menten kinetics. The non-linear reaction-diffusion equations for substrate and product concentrations have been approximated analytically. Employing two different semi-analytical methods, Akbari-Ganji's method (AGM) and the modified Adomian decomposition method (MADM), to compute the dimensionless steady-state solutions to the system of non-linear differential equations for all values of reaction parameters. In addition, the dynamics of the mean integrated effectiveness factor of penicillin acylase in porous spherical particles have been presented for the determination of the local effectiveness factor. In order to gauge the potency of our proposed solution, we compare two semi-analytical results with a numerical result that are in good agreement across the whole concentration range. The proposed formulation aims to simulate the dynamic performance of the system utilizing the parameters and would enhance the determination of the optimum particle size for enzyme catalysts.

Compound effect and mechanism of oxidative damage induced by nanoplastics and benzo [a] pyrene

Nanoplastics and polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in soil environments. In order to objectively evaluate the toxic interaction between polystyrene nanoplastics (PS NPs) and benzo [a] pyrene (BaP), oxidative damage at the level of earthworm cells and biomacromolecules was investigated by experiments combined with molecular dynamics simulation. Studies on cells reveal that PS NPs and BaP had synergistic toxicity when it came to causing oxidative stress. Cellular reactive oxygen species (ROS) levels under combined pollutant exposure were 24% and 19% higher, respectively than when PS NPs and BaP were exposed alone (compared to the blank group). In addition, BaP and PS NPs inhibited the ability of CAT to decompose H2O2 by affecting the structure of the proximal amino acid Tyr 357 in the active center of CAT, which exacerbated oxidative stress to a certain extent. Therefore, the synergistic toxic effect of BaP and PS NPs is due to the mutual complement of the two to the induction of protein structural looseness, and the strengthening of the stability of the conjugate (CAT-BaP-PS) under the weak interaction. This work provides a new perspective and approach on how to talk about the toxicity of combined pollutants.

An insight into microbial sources, classification, and industrial applications of xylanases: A rapid review

Endo 1,4-β-d-xylanases (EC3.2.1.8) are one of the key lignocellulose hydrolyzing enzymes. Xylan, which is present in copious amounts on earth, forms the primary substrate of endo-xylanases, which can unchain the constituent monosaccharides linked via β-1,4-glycosidic bonds from the xylan backbone. Researchers have shown keen interest in the xylanases belonging to glycoside hydrolase families 10 and 11, whereas those placed in other glycoside hydrolase families are yet to be investigated. Various microbes such as bacteria and fungi harbor these enzymes for the metabolism of their lignocellulose fibers. These microbes can be used as miniature biofactories of xylanase enzymes for a plethora of environmentally benign applications in pulp and paper industry, biofuel production, and for improving the quality of food in bread baking and fruit juice industry. This review highlights the potential of microbes in production of xylanase for industrial biotechnology.

Lactate oxidase/vSIRPα conjugates efficiently consume tumor-produced lactates and locally produce tumor-necrotic H2O2 to suppress tumor growth

Aggressive tumor formation often leads to excessive anaerobic glycolysis and massive production and accumulation of lactate in the tumor microenvironment (TME). To significantly curb lactate accumulation in TME, in this study, lactate oxidase (LOX) was used as a potential therapeutic enzyme and signal regulatory protein α variant (vSIRPα) as a tumor cell targeting ligand. SpyCatcher protein and SpyTag peptide were genetically fused to LOX and vSIRPα, respectively, to form SC-LOX and ST-vSIRPα and tumor-targeting LOX/vSIRPα conjugates were constructed via a SpyCatcher/SpyTag protein ligation system. LOX/vSIRPα conjugates selectively bound to the CD47-overexpressing mouse melanoma B16-F10 cells and effectively consumed lactate produced by the B16-F10 cells, generating adequate amounts of hydrogen peroxide (H₂O₂), which induces drastic necrotic tumor cell death. Local treatments of B16-F10 tumor-bearing mice with LOX/vSIRPα conjugates significantly suppressed B16-F10 tumor growth in vivo without any severe side effects. Tumor-targeting vSIRPα may allow longer retention of LOX in tumor sites, effectively consuming surrounding lactate in TME and locally generating adequate amounts of cytotoxic H₂O₂ to suppress tumor growth. The approach restraining the local lactate concentration and H₂O₂ in TME using LOX and vSIRPα could offer new opportunities for developing enzyme/targeting ligand conjugate-based therapeutic tools for tumor treatment.

Enzyme Immobilization Technologies and Industrial Applications

Enzymes play vital roles in diverse industrial sectors and are essential components of many industrial products. Immobilized enzymes possess higher resistance to environmental changes and can be recovered/recycled easily when compared to the free forms. The primary benefit of immobilization is protecting the enzymes from the harsh environmental conditions (e.g., elevated temperatures, extreme pH values, etc.). The immobilized enzymes can be utilized in various large-scale industries, e.g., medical, food, detergent, textile, and pharmaceutical industries, besides being used in water treatment plants. According to the required application, a suitable enzyme immobilization technique and suitable carrier materials are chosen. Enzyme immobilization techniques involve covalent binding, encapsulation, entrapment, adsorption, etc. This review mainly covers enzyme immobilization by various techniques and their usage in different industrial applications starting from 1992 until 2022. It also focuses on the multiscale operation of immobilized enzymes to maximize yields of certain products. Lastly, the severe consequence of the COVID-19 pandemic on global enzyme production is briefly discussed.

Advances in the One-Step Approach of Polymeric Materials Using Enzymatic Techniques

The formulation in which biochemical enzymes are administered in polymer science plays a key role in retaining their catalytic activity. The one-step synthesis of polymers with highly sequence-controlled enzymes is a strategy employed to provide enzymes with higher catalytic activity and thermostability in material sustainability. Enzyme-catalyzed chain growth polymerization reactions using activated monomers, protein-polymer complexation techniques, covalent and non-covalent interaction, and electrostatic interactions can provide means to develop formulations that maintain the stability of the enzyme during complex material processes. Multifarious applications of catalytic enzymes are usually attributed to their efficiency, pH, and temperature, thus, progressing with a critical structure-controlled synthesis of polymer materials. Due to the obvious economics of manufacturing and environmental sustainability, the green synthesis of enzyme-catalyzed materials has attracted significant interest. Several enzymes from microorganisms and plants via enzyme-mediated material synthesis have provided a viable alternative for the appropriate synthesis of polymers, effectively utilizing the one-step approach. This review analyzes more and deeper strategies and material technologies widely used in multi-enzyme cascade platforms for engineering polymer materials, as well as their potential industrial applications, to provide an update on current trends and gaps in the one-step synthesis of materials using catalytic enzymes.

Identification of New Amylolytic Enzymes from Marine Symbiotic Bacteria of Bacillus Species

α-amylases are one of the most common and important industrial enzymes widely used in various industries. The present study was conducted with the aim of isolating and identifying symbiotic α-amylase enzyme-producing bacteria in the intestine of Silago Sihama and Rasterliger Canagorta fish living in Qeshm Island, Hormozgan. The intestinal symbiotic bacteria of these species were isolated using nutrient agar culture medium; then, α-amylase producing bacteria were screened using a special culture medium containing starch and the Lugol’s solution test. The α-amylase enzyme activity of enzyme-producing bacteria was measured using the starch substrate. Finally, bacteria with the highest enzyme activity were selected and identified by the 16S rRNA gene sequence analysis. The results showed that out of 22 isolated bacteria, 10 were able to grow in a special culture medium, and 5 strains of these 10 bacteria had the ability to produce relatively stronger halos. The four bacterial strains belonging to the genus Bacillus that had the highest α-amylase enzyme activity were identified and registered in the NCBI gene database as B. subtilis strains HR13, HR14, HR15, and HR16. Among these four strains, two strains of B. subtilis, HR13 and HR16, displayed high enzyme activity and maximum activity at 60 °C at pH values of 5 and 7, respectively. α-Amylase enzymes isolated from marine symbiotic bacteria of Bacillus species can be considered potential candidates for application in various industries.