Immobilization of α-amylase from mung beans (Vigna radiata) on Amberlite MB 150 and chitosan beads: A comparative study

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.

Modifying Thermostability and Reusability of Hyperthermophilic Mannanase by Immobilization on Glutaraldehyde Cross-Linked Chitosan Beads

In the current study, the purified β-mannanase (Man/Cel5B) from Thermotoga maritima was immobilized on glutaraldehyde cross-linked chitosan beads. The immobilization of Man/Cel5B on chitosan beads was confirmed by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. After immobilization, the protein loading efficiency and immobilization yield were found to be 73.3% and 71.8%, respectively. The optimum pH for both free and immobilized enzymes was found to be pH 5.5. However, the optimum temperature of immobilized Man/Cel5B increased by 10 °C, from 85 °C (free Man/Cel5B) to 95 °C (Immobilized). The half-life of free and immobilized enzymes was found to be 7 h and 9 h, respectively, at 85 °C owing to the higher thermostability of immobilized Man/Cel5B. The increase in thermostability was also demonstrated by an increase in the energy of deactivation (209 kJmol⁻¹) for immobilized enzyme compared to its native form (92 kJmol⁻¹), at 85 °C. Furthermore, the immobilized Man/Cel5B displayed good operational stability as it retained 54% of its original activity after 15 repeated catalytic reactions concerning its free form.

Comparative study of covalent and hydrophobic interactions for α-amylase immobilization on cellulose derivatives

Indispensability of enzymes in living systems, their unique characteristics and simultaneous focus on development of greener methods have led to substitution of various chemical reactions by enzyme catalyzed reactions. One of the aspects in enzyme research is immobilization of enzymes. Immobilization provides a platform for reusability of significant enzymes. Varieties of methods have been explored for enzyme immobilization such as entrapment, adsorption, ionic interactions etc. Keeping in view the industrial utility of α-Amylase in leather, paper and other industries related to starch hydrolysis, we immobilized α-Amylase on cellulose isolated from banana peel. In present study, two different methods of immobilization - covalent bonding (Cellulose Dialdehyde as a support) and hydrophobic interactions (Nano Cellulose- Cetyl Trimethyl Ammonium Bromide) were used. Cellulose obtained from bio-waste has been characterized using Fourier transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD). In this comparative study, Cellulose Dialdehyde (CDA) immobilized enzyme depicts high reusability, good enzyme loading, storage capacity up to 49 days, optimum pH 6, optimum temperature 95 °C, good pH and thermal stability as compared to native enzyme having optimum pH and temperature of 7 and 37 °C. On the contrary, nanocellulose - Cetyl Trimethyl Ammonium Bromide (NC-CTAB) matrix shows good enzyme loading and optimum pH shift of about 3 units but poor recyclability. Outcome of this study presents the promising nature of covalent mode of immobilization for industrial use.

Lipase from Rhizopus oryzae R1: in-depth characterization, immobilization, and evaluation in biodiesel production

Background

Rhizopus species is among the most well-known lipase producers, and its enzyme is suitable for use in many industrial applications. Our research focuses on the production of lipase utilizing waste besides evaluating its applications.

Results

An extracellular lipase was partially purified from the culture broth of Rhizopus oryzae R1 isolate to apparent homogeneity using ammonium sulfate precipitation followed by desalting via dialysis. The partially purified enzyme was non-specific lipase and the utmost activity was recorded at pH 6, 40 °C with high stability for 30 min. The constants K_m and V_max, calculated from the Lineweaver-Burk plot, are 0.3 mg/mL and 208.3 U/mL, respectively. Monovalent metal ions such as Na⁺ (1 and 5 mM) and K⁺ (5 mM) were promoters of the lipase to enhance its activity with 110, 105.5, and 106.5%, respectively. Chitosan was used as a perfect support for immobilization via both adsorption and cross-linking in which the latter method attained immobilization efficiency of 99.1% and reusability of 12 cycles. The partially purified enzyme proved its ability in forming methyl oleate (biodiesel) through the esterification of oleic acid and transesterification of olive oil.

Conclusion

The partially purified and immobilized lipase from Rhizopus oryzae R1 approved excellent efficiency, reusability, and a remarkable role in detergents and biodiesel production.

Utilization of different polymers for the improvement of catalytic properties and recycling efficiency of bacterial maltase

Current study deals with the comparative study related to immobilization of maltase using synthetic (polyacrylamide) and non-synthetic (calcium alginate, agar-agar and agarose) polymers via entrapment technique. Polyacrylamide beads were formed by cross-linking of monomers, agar-agar and agarose through solidification while alginate beads were prepared by simple gelation. Results showed that the efficiency of enzyme significantly improved after immobilization and among all tested supports agar-agar was found to be the most promising and biocompatible for maltase in terms of immobilization yield (82.77%). The catalytic behavior of maltase was slightly shifted in terms of reaction time (free enzyme, agarose and polyacrylamide: 5.0 min; agar-agar and alginate: 10.0 min), pH (free enzyme, alginate and polyacrylamide: 6.5; agar-agar, agarose: 7.0) and temperature (free enzyme: 45 °C; alginate: 50 °C; polyacrylamide: 55 °C; agarose: 60 °C; agar-agar: 65 °C). Stability profile of immobilized maltase also revealed that all the supports utilized have significantly enhanced the activity of maltase at higher temperatures then its free counterpart. However, recycling data showed that agar-agar entrapped maltase retained 20.0% of its initial activity even after 10 cycles followed by agarose (10.0%) while polyacrylamide and alginate showed no activity after 8 and 6 cycles respectively.

Application of Immobilized Enzymes in Food Industry

Enzymes are macromolecular biocatalysts, widely used in food industry. In applications, enzymes are often immobilized on inert and insoluble carriers, which increase their efficiency due to multiple reusability. The properties of immobilized enzymes depend on the immobilization method and the carrier type. The choice of the carrier usually concerns the biocompatibility, chemical and thermal stability, insolubility under reaction conditions, capability of easy regeneration and reusability, as well as cost efficiency. In this review, we provide an overview of various carriers for enzyme immobilization, with the primary focus on food industry.

Enzyme Immobilization on Metal-Organic Framework (MOF): Effects on Thermostability and Function

MOFs are porous materials with adjustable porosity ensuing a tenable surface area and stability. MOFs consist of metal containing joint where organic ligands are linked with coordination bonding rendering a unique architecture favouring the diverse applications in attachment of enzymes, Chemical catalysis, Gases storage and separation, biomedicals. In the past few years immobilization of soluble enzymes on/in MOF has been the topic of interest for scientists working in diverse field. The activity of enzyme, reusability, storage, chemical and thermal stability, affinity with substrate can be greatly improved by immobilizing of enzyme on MOFs. Along with improvement in enzymes properties, the high loading of enzyme is also observed while using MOFs as immobilization support. In this review a detail study of immobilization on/in Metalorganic Frameworks (MOFs) have been described. Furthermore, strategies for the enzyme immobilization on MOFs and resulting in improved catalytic performance of immobilized enzymes have been reported.

Heterologous expression, purification, immobilization and characterization of recombinant α-amylase AmyLa from Laceyella sp. DS3

AmyLa α-amylase gene from Laceyella sp. DS3 was heterologously expressed in E. coli BL21. E. coli BL21 maximally expressed AmyLa after 4 h of adding 0.02 mM IPTG at 37 °C. The recombinant AmyLa α-amylase was purified 2.19-fold through gel filtration and ion exchange chromatography. We immobilized the purified recombinant AmyLa α-amylase on four carriers; chitosan had the best efficiency. The recombinant free and the immobilized AmyLa α-amylase showed optimum activity in the pH ranges of 6.0-7.0 and 4.0-7.0, respectively and possessed an optimum temperature of 55 °C. The free enzyme had activation energy, Km, and Vmax of 291.5 kJ, 1.5 mg/ml, and 6.06 mg/min, respectively. The immobilized enzyme had activation energy, Km, and Vmax of 309.74 kJ, 6.67 mg/ml, and 50 mg/min, respectively. The immobilized enzyme was calcium-independent and insensitive (relative to the free enzyme) to metals. It could also be reused for seven cycles.

Modification of chitosan-bead support materials with L-lysine and L-asparagine for α-amylase immobilization

Maltose syrups have got wide-range utilizations in a variety of applications from bakery to drug-development. α-Amylases are among the most widely utilized industrial enzymes due to their high specificity in production of maltose syrup from starch. However, enzymes are not stable in ex vivo conditions towards alteration in pH, temperature, and such other parameters as high salt concentrations and impurities, where immobilization is required to advance the stability of the enzyme with which approach the requirement of isolation of the enzyme from media is eliminated as well. In this study, Termamyl^® α-amylase was immobilized on the none-modified chitosan beads (NMCB), L-lysine-modified chitosan beads (LMCB), and L-asparagine-modified chitosan beads (AMCB) to assess effects of the support material on optimum conditions and kinetic parameters of the α-amylase activity in production of maltose from starch. Immobilization on NMCB, LMCB, and AMCB puts a strong influence on optimum pH, optimum temperature, stability, and kinetic parameters of α-amylase. Modification of chitosan beads with L-lysine and L-asparagine dramatically altered the overall immobilization yield, and enzyme's response to pH and temperature variations and the kinetic parameters. AMCB provided the best immobilization yield (49%), while LMCB only improved the yield by 2% from 22 to 24%.

Metallic/bimetallic magnetic nanoparticle functionalization for immobilization of α-amylase for enhanced reusability in bio-catalytic processes

Novel magnetic nanoparticles coated with silica and gold were synthesized for immobilization of α-amylase enzyme and characterized with Fourier transform infrared spectroscopy, transmission electron microscopy. Effect of various limiting factors such as substrate concentration, temperature, and pH on the catalytic activity of enzyme was investigated. The optimum pH for free and immobilized enzyme was found unaffected (7.0), whereas optimum temperature for the enzyme activity was increased from 60°C for free enzyme to 80°C for immobilized counterpart. The gains in catalytic attributes concomitant to ease of recovery of the enzyme reflect the potential of the approach and the product to be useful for the enzymatic bioprocessing. The Michaelis-Menten constant (Km) value of the immobilized α-amylase was higher than that of free α-amylase, whereas maximum velocity (Vmax), and turn over number (Kcat), values were almost similar. Immobilized α-amylase maintained 60% of the enzyme activity even after recycling ten times.

Efficient Immobilization of Porcine Pancreatic α-Amylase on Amino-Functionalized Magnetite Nanoparticles: Characterization and Stability Evaluation of the Immobilized Enzyme

The potential of the modified magnetic nanoparticles for covalent immobilization of porcine pancreatic α-amylase has been investigated. The synthesis and immobilization processes were simple and fast. The co-precipitation method was used for synthesis of magnetic iron oxide (Fe₃O₄) nanoparticles (NPs) which were subsequently coated with silica through sol-gel reaction. The amino-functionalized NPs were prepared by treating silica-coated NPs with 3-aminopropyltriethoxysilane followed by covalent immobilization of α-amylase by glutaraldehyde. The optimum enzyme concentration and incubation time for immobilization reaction were 150 mg and 4 h, respectively. Upon this immobilization, the α-amylase retained more than 50 % of its initial specific activity. The optimum pH for maximal catalytic activity of the immobilized enzyme was 6.5 at 45 °C. The kinetic studies on the immobilized enzyme and its free counterpart revealed an acceptable change of K_m and V_max. The Km values were found as 4 and 2.5 mM for free and immobilized enzymes, respectively. The V_max values for the free and immobilized enzymes were calculated as 1.75 and 1.03 μmol mg^-1 min^-1, in order, when starch was used as the substrate. A quick separation of immobilized amylase from reaction mixture was achieved when a magnetically active support was applied. In comparison to the free enzyme, the immobilized enzyme was thermally stable and was reusable for 9 cycles while retaining 68 % of its initial activity.

α-Amylase immobilization onto functionalized graphene nanosheets as scaffolds: Its characterization, kinetics and potential applications in starch based industries

α-Amylase is imperative for starch and its deriviatized industries. Functionalized graphene sheets were tailored and optimized as scaffold for α-amylase immobilization using Response Surface Methodology based on Box–Behnken design, with an overall immobilization efficiency of 85.16%. Analysis of variance provided adequacy to the mathematical model for further studies. Native and immobilized functionalized graphene were characterized using transmission and scanning electron microscopy, followed by Fourier transform infrared (FTIR) spectroscopy. Wheat α-amylase conjugated with functionalized graphene sheets were visually evident on transmission and scanning micrographs while the FTIR spectra showed interplay of various chemical interactions and bonding, during and after immobilization. Optimum pH and optimum temperature for immobilized enzyme though remained unchanged but showed broader range whereas K_m showed a slight decrease (1.32 mg/mL). It also showed enhanced thermal and storage stability and retained 73% residual activity after 10 uses. These ensemble of properties and non-toxic nature of functionalized graphene, makes it viable to be absorbed commercially in starch processing industries.

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α-Amylase was optimally anchored on functionalized graphene nanosheets using RSM.

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This multipoint attachment resulted in improved features for its industrial viability.

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With decreased K_m, bioconjugate ascertains increased affinity for substrate hydrolysis.

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Showed improved thermostability, reusability and storage stability over free enzyme.

Immobilization of acid phosphatase from Vigna aconitifolia seeds on chitosan beads and its characterization

Acid phosphatase isolated from Vigna aconitifolia seeds was immobilized onto glutaraldehyde activated chitosan beads by crosslinking method. Chitosan beads activated with 2% of glutaraldehyde have demonstrated maximum immobilization yield (∼ 83%). The immobilized enzyme showed optimum activity at pH 7.0, while soluble form was maximally active in acidic range (pH 5.0). With respect to free form, immobilized acid phosphatase showed better activity in alkaline range. On the other side, immobilization does not affect the optimum temperature range i.e., both, soluble and immobilized acid phosphatase exhibited maximum activity at 60 °C. The Km and Vmax values for the immobilized enzyme were calculated to be 0.37 mM and 13.5 U/mg. The immobilization on chitosan beads enhanced the shelf life of acid phosphatase. The immobilized enzyme retained its more than 50% hydrolytic activity for approximately two months. The immobilized acid phosphatase was reusable for more than 40 cycles of reaction.

Cicer α-galactosidase immobilization onto functionalized graphene nanosheets using response surface method and its applications

Cicer α-galactosidase was immobilized onto functionalized graphene with immobilization efficiency of 84% using response surface methodology (Box-Behnken design). The immobilized enzyme had higher thermal stability than the soluble one, attractive for industrial applications. Immobilization of the enzyme lowered the Km to 1/3rd compared to the soluble enzyme. Raffinose family oligosaccharides (RFOs) are mainly responsible for flatulence by taking soybean derived food products. The immobilized enzyme can be used effectively for the hydrolysis of RFOs. After ten successive runs, the immobilized enzyme still retained approximately 60% activity, with soybean RFOs. The easy availability of enzyme source, ease of its immobilization on matrices, non-toxicity, increased stability of immobilized enzyme and effective hydrolysis of RFOs increase the Cicer α-galactosidase application in food processing industries.

Cicer α-galactosidase immobilization onto chitosan and Amberlite MB-150: optimization, characterization, and its applications

Cicer α-galactosidase was immobilized onto chitosan and Amberlite with immobilization efficiency of 62% and 51%, respectively. Compared to soluble enzyme, immobilized enzyme had a broader operational pH range and thermal stability. Temperature optimum for chitosan immobilized enzyme and Amberlite immobilized enzyme was 70°C, whereas it was 50°C for soluble enzyme. After 120days storage at 4°C chitosan immobilized enzyme retained 54% activity and Amberlite immobilized enzyme showed 32% activity. After using the immobilized enzymes 12 times, chitosan immobilized enzyme showed 52% activity, while Amberlite immobilized enzyme retained 22% activity with pNPGal. The immobilized enzyme exhibited higher K(m) compared to the soluble enzyme. Raffinose family oligosaccharides (RFOs) are mainly responsible for flatulence on taking of soybean derived food products. Immobilized enzyme can be used effectively for the hydrolysis of RFOs. After five runs, chitosan and Amberlite immobilized enzyme retained 53% and 34% activity, respectively with soybean RFOs. The easy availability of enzyme source, ease of its immobilization on matrices, non-toxicity and low cost of matrices, increased stability of immobilized enzyme, and effective hydrolysis of RFOs makes it a suitable product with potential applications at industries.

Enzymes in food processing: a condensed overview on strategies for better biocatalysts

Food and feed is possibly the area where processing anchored in biological agents has the deepest roots. Despite this, process improvement or design and implementation of novel approaches has been consistently performed, and more so in recent years, where significant advances in enzyme engineering and biocatalyst design have fastened the pace of such developments. This paper aims to provide an updated and succinct overview on the applications of enzymes in the food sector, and of progresses made, namely, within the scope of tapping for more efficient biocatalysts, through screening, structural modification, and immobilization of enzymes. Targeted improvements aim at enzymes with enhanced thermal and operational stability, improved specific activity, modification of pH-activity profiles, and increased product specificity, among others. This has been mostly achieved through protein engineering and enzyme immobilization, along with improvements in screening. The latter has been considerably improved due to the implementation of high-throughput techniques, and due to developments in protein expression and microbial cell culture. Expanding screening to relatively unexplored environments (marine, temperature extreme environments) has also contributed to the identification and development of more efficient biocatalysts. Technological aspects are considered, but economic aspects are also briefly addressed.