Immobilization of soybean (Glycine max) α-amylase onto Chitosan and Amberlite MB-150 beads: Optimization and characterization

Starch Biocatalyst Based on α-Amylase-Mg/Al-Layered Double Hydroxide Nanohybrids

The design of new biocatalysts through the immobilization of enzymes, improving their stability and reuse, plays a major role in the development of sustainable methodologies toward the so-called green chemistry. In this work, α-amylase (AAM) biocatalyst based on Mg3Al-layered double-hydroxide (LDH) matrix was successfully developed with the adsorption method. The adsorption process was studied and optimized as a function of time and enzyme concentration. The biocatalyst was characterized, and the mechanism of interaction between AAM and LDH, as well as the immobilization effects on the catalytic activity, was elucidated. The adsorption process was fast and irreversible, thus yielding a stable biohybrid material. The immobilized AAM partially retained its enzymatic activity, and the biocatalyst rapidly hydrolyzed starch in an aqueous solution with enhanced efficiency at intermediate loading values of ca. 50 mg/g of AAM/LDH. Multiple attachments through electrostatic interactions affected the conformation of the immobilized enzyme on the LDH surface. The biocatalyst was successfully stored in its dry form, retaining 100% of its catalytic activity. The results reveal the potential usefulness of a LDH compound as a support of α-amylase for the hydrolysis of starch that may be applied in industrial and pharmaceutical processes as a simple, environmentally friendly, and low-cost biocatalyst.

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.

Immobilization of α-Amylase onto Luffa operculata Fibers

A commercial amylase (amy) was immobilized by adsorption onto Luffa operculata fibers (LOFs). The derivative LOF-amy presented capacity to hydrolyze starch continuously and repeatedly for over three weeks, preserving more than 80% of the initial activity. This system hydrolyzed more than 97% of starch during 5 min, at room temperature. LOF-amy was capable to hydrolyze starch from different sources, such as maize (93.96%), wheat (85.24%), and cassava (79.03%). A semi-industrial scale reactor containing LOF-amy was prepared and showed the same yield of the laboratory-scale system. After five cycles of reuse, the LOF-amy reactor preserved over 80% of the initial amylase activity. Additionally, the LOF-amy was capable to operate as a kitchen grease trap component in a real situation during 30 days, preserving 30% of their initial amylase activity.

Enzyme immobilization: an overview on techniques and support materials

The current demands of the world’s biotechnological industries are enhancement in enzyme productivity and development of novel techniques for increasing their shelf life. These requirements are inevitable to facilitate large-scale and economic formulation. Enzyme immobilization provides an excellent base for increasing availability of enzyme to the substrate with greater turnover over a considerable period of time. Several natural and synthetic supports have been assessed for their efficiency for enzyme immobilization. Nowadays, immobilized enzymes are preferred over their free counterpart due to their prolonged availability that curtails redundant downstream and purification processes. Future investigations should endeavor at adopting logistic and sensible entrapment techniques along with innovatively modified supports to improve the state of enzyme immobilization and provide new perspectives to the industrial sector.

Immobilization of β-galactosidase onto functionalized graphene nano-sheets using response surface methodology and its analytical applications

Background

β-Galactosidase is a vital enzyme with diverse application in molecular biology and industries. It was covalently attached onto functionalized graphene nano-sheets for various analytical applications based on lactose reduction.

Methodology/Principal Findings

Response surface methodology based on Box-Behnken design of experiment was used for determination of optimal immobilization conditions, which resulted in 84.2% immobilization efficiency. Native and immobilized functionalized graphene was characterized with the help of transmission and scanning electron microscopy, followed by Fourier transform infrared (FTIR) spectroscopy. Functionalized graphene sheets decorated with islands of immobilized enzyme were evidently visualized under both transmission and scanning electron microscopy after immobilization. FTIR spectra provided insight on various chemical interactions and bonding, involved during and after immobilization. Optimum temperature and energy of activation (E_a) remains unchanged whereas optimum pH and K_m were changed after immobilization. Increased thermal stability of enzyme was observed after conjugating the enzyme with functionalized graphene.

Significance

Immobilized β-galactosidase showed excellent reusability with a retention of more than 92% enzymatic activity after 10 reuses and an ideal performance at broad ranges of industrial environment.

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.

Optimisation of immobilisation conditions for chick pea β-galactosidase (CpGAL) to alkylamine glass using response surface methodology and its applications in lactose hydrolysis

Response surface methodology was advantageously used to optimally immobilise a β-galactosidase from chick pea onto alkylamine glass using Box-Behnken experimental design, resulting in an overall 91% immobilisation efficiency. Analysis of variance was performed to determine the adequacy and significance of the quadratic model. Immobilised enzyme showed a shift in the optimum pH; however, optimum temperature remained unaffected. Thermal denaturation kinetics demonstrated significant improvement in thermal stability of the enzyme after immobilisation. Galactose competitively inhibits the enzyme in both soluble and immobilised conditions. Lactose in milk whey was hydrolysed at comparatively higher rate than that of milk. Immobilised enzyme showed excellent reusability with retention of more than 82% enzymatic activity after 15 uses. The immobilised enzyme was found to be fairly stable in both dry and wet conditions for three months with retention of more than 80% residual activity.

Effect of tin oxide nanoparticle binding on the structure and activity of α-amylase from Bacillus amyloliquefaciens

Proteins adsorbed on nanoparticles (NPs) are being used in biotechnology, biosensors and drug delivery. However, understanding the effect of NPs on the structure of proteins is still in a nascent state. In the present paper tin oxide (SnO2) NPs were synthesized by the reaction of SnCl4·5H2O in methanol via the sol-gel method and characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The binding of these SnO2-NPs with α-amylase was investigated by using UV-vis, fluorescence and circular dichroism (CD) spectroscopic techniques. A strong quenching of tryptophan fluorescence intensity in α-amylase was observed due to formation of a ground state complex with SnO2-NPs. Far-UV CD spectra showed that the secondary structure of α-amylase was changed in the presence of NPs. The Michaelis-Menten constant (K(m)), was found to be 26.96 and 28.45 mg ml(-1), while V(max) was 4.173 and 3.116 mg ml(-1) min(-1) for free and NP-bound enzyme, respectively.

Fermentative Production and Thermostability Characterization of α Amylase from Aspergillus Species and Its Application Potential Evaluation in Desizing of Cotton Cloth

The production of extracellular amylase was investigated employing our laboratory isolate, Aspergillus niger sp. MK 07 and effect of process variables on enzyme production, was studied in a fermentor. It was found that amylase production was maximum when the fermentor volume was maintained at 70%, rate of agitation at 250 rpm, air supply at 2.5 vvm, inoculum concentration of 10%, and a pH of 5.0. Highest enzyme production obtained under all optimized conditions was 1734 U/mL with sucrose as carbon substrate and corn steep liquor as nitrogen source. Enzyme purification studies by ammonium sulphate precipitation and Sephadex G-100 chromatography was evaluated for obtaining purified enzyme. Thermostability of amylase were evaluated with varying concentrations from 0.2 to 0.5 M concentrations of calcium chloride and the highest activity obtained was 3115 U/mL with 0.3 M calcium chloride at 55°C. Effect of temperature and pH on the activity of purified enzyme was evaluated and the purified enzyme showed an activity till 75°C and a pH of 6.5. Application potential of partially purified alpha amylase on desizing of cotton cloth was evaluated with varying enzyme concentrations from 50 to 500 U/mL and the highest desizing activity was found to be at 300 U/mL.