Determination of Activation Energies and the Optimum Temperatures of Hydrolysis of Starch by α-Amylase from Porcine Pancreas

Sequential cultivation method for β-fructofuranosidase production from Aspergillus tamarii URM4634, evaluation of their biochemical and kinetic/thermodynamic characteristics, and application on sucrose hydrolysis

The present study focused on evaluating the sequential fermentation (SF) method for FFase production from Aspergillus tamarii URM4634 using soybean bran as substrate. The SF was performed using soybean bran as substrate at 72 h and 30 °C and the maximum hydrolytic activity (44.00 U mL-1), corresponding to an increase of 2.98-fold to about SmF using sucrose as substrate. Already the maximum transfructosylating activity was 26.10 U mL-1. The FFase presents maximum hydrolytic activity at pH 5.0-6.0 and transfructosylating at pH 6.0 and 60 °C for both enzyme activities. The enzyme showed a typical hydrolytic kinetic profile evidenced by more affinity by sucrose hydrolysis reaction than the fructosyl transfer one. From kinetic and thermodynamic data of thermal denaturation, it was observed that the enzyme presents suitable at 55 °C, evidenced by the large half-life (990.21 min) and D values (3289.41 min). The maximum release of reducing sugars (8.45 g L-1) was obtained in hydrolysis of 20% sucrose during 180 min. The results obtained for FFase production by SF proved that this method can be used satisfactorily for sucrose-degrading enzymes and can contribute to the development of the SF technique to produce different industrial-interest enzymes.

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.

An Accessible Method to Improve the Stability and Reusability of Porcine Pancreatic α-Amylase via Immobilization in Gellan-Based Hydrogel Particles Obtained by Ionic Cross-Linking with Mg2+ Ions

Amylase is an enzyme used to hydrolyze starch in order to obtain different products that are mainly used in the food industry. The results reported in this article refer to the immobilization of α-amylase in gellan hydrogel particles ionically cross-linked with Mg2+ ions. The obtained hydrogel particles were characterized physicochemically and morphologically. Their enzymatic activity was tested using starch as a substrate in several hydrolytic cycles. The results showed that the properties of the particles are influenced by the degree of cross-linking and the amount of immobilized α-amylase enzyme. The temperature and pH at which the immobilized enzyme activity is maximum were T = 60 °C and pH = 5.6. The enzymatic activity and affinity of the enzyme to the substrate depend on the particle type, and this decreases for particles with a higher cross-linking degree owing to the slow diffusion of the enzyme molecules inside the polymer's network. By immobilization, α-amylase is protected from environmental factors, and the obtained particles can be quickly recovered from the hydrolysis medium, thus being able to be reused in repeated hydrolytic cycles (at least 11 cycles) without a substantial decrease in enzymatic activity. Moreover, α-amylase immobilized in gellan particles can be reactivated via treatment with a more acidic medium.