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    Öğe
    Covalent immobilization of Aspergillus oryzae ?-galactosidase and Bacillus licheniformis protease with Amino-Multi Walled Carbon Nanotubes
    (Tarbiat Modares University, 2024) Taher, Alan Yaseen; Alizadeh, Mohammad; Aslan, Yakup
    This study was carried out with the aim of covalent immobilization of Aspergillus oryzae beta-galactosidase and Bacillus licheniformis protease on multi-walled amino-carbon nanotubes. In this method, fractional 2k design was used to study the effect of seven continuous factors (activation pH, glutaraldehyde molarity, activation time, buffer solution pH, buffer solution molarity, MWCNT-NH3-glutaraldehyde amount and stabilization time) on the stabilization efficiency and enzyme activity. . Design-expert software was used to analyze data and draw graphs. The results showed that the aforementioned factors predict the level of enzyme activity of Bacillus licheniformis protease and Aspergillus oryzae beta-galactosidase with correlation coefficients of 0.80 and 0.92 at the rate of 77 and 88%, respectively. Also, the correlation coefficient of the covalent fixation efficiency model of Aspergillus oryzae beta-galactosidase and Bacillus licheniformis protease on multi-walled carbon nanotubes was 0.89 and 0.82, respectively, and the studied factors were able to determine the covalent fixation beta efficiency, respectively. Aspergillus oryzae galactosidase and Bacillus licheniformis protease on multi-walled amino-carbon nanotubes predict 83 and 77%, respectively. © 2024 Tarbiat Modares University. All rights reserved.
  • Küçük Resim
    Öğe
    Improved catalytic activity of aspergillus oryzae β-galactosidase by covalent immobilization on eupergit cm
    (Descember, 2018) Aslan, Yakup; Taher, Alan Yaseen; Cavidoğlu, İsa
    In this study, Aspergillus oryzae β-Galactosidase (AOG) was immobilized onto Eupergit CM. By optimizing the immobilization conditions such as pH and molarity of immobilization buffer, enzyme/support ratio and duration of immobilization, 100.00% immobilization yield and 129.82% activity yield was achieved. The optimum temperature (55 °C) of free enzyme was not changed while optimum pH of free enzyme was shifted from 4.5 to 5.5 after immobilization. Kinetic constants for free and immobilized enzyme were also determined by using the Lineweaver-Burk plot. The Km values of the free and immobilized enzymes were determined to be 307.7 and 234.2 g / L respectively, while the Vmax values were determined to be 0.366 g D-Glucose / L.min and 0.415 g D-Glucose / L.min respectively. The operational and storage stabilities of immobilized enzyme were also studied. The activity of immobilized enzyme decreased to 99.3% after repeated twenty usage while decreased to 98.3% after fifteen days of storage. Further, the immobilized enzyme was used for the hydrolyzing the cow's milk lactose. By using the immobilized enzyme, the milk lactose was completely hydrolyzed in four hours. Consequently, immobilized AOG can be used in the industrial production of lactose-free cow's milk.
  • [ X ]
    Öğe
    The covalent immobilization of ?-galactosidase from Aspergillus oryzae and alkaline protease from Bacillus licheniformis on amino-functionalized multi-walled carbon nanotubes in milk
    (Cell Press, 2024) Taher, Alan Yaseen; Alizadeh, Mohammad; Aslan, Yakup
    This study aimed was to covalently immobilize beta-galactosidase from Aspergillus oryzae and protease from Bacillus licheniformis on amino-functionalized multi-walled carbon nanotubes. In this study, a two-level factorial design was employed to investigate the impact of seven continuous variables (activation pH, glutaraldehyde molarity, activation time (0-8 h), buffer solution pH (8-0), buffer solution molarity, MWCNT-NH (2) -glutaraldehyde quantity, and stabilization time (0-180 h)) on the immobilization efficiency and enzymatic activity of protease and beta-galactosidase. Furthermore, the effect of time on the percentage of enzymatic activity was examined during specific intervals (24, 48, 72, 96, and 120 h) of the immobilization process. The analysis of variance results for protease enzymatic activity revealed a notable influence of the seven variables on immobilization efficiency and enzymatic activity. Additionally, the findings indicate that activation time, buffer pH, MWCNT-NH (2) -glutaraldehyde quantity, and stabilization time significantly affect the activity of the protease enzyme. The interplay between buffer pH and stabilization time is also significant. Indeed, both activation time and the quantity of MWCNT-NH (2) -glutaraldehyde exert a reducing effect on enzyme activity. Notably, the influence of MWCNT-NH (2) -glutaraldehyde quantity is more significant (p < 0.05). In terms of beta-galactosidase enzymatic activity, the study results highlight that among the seven variables considered, only the glutaraldehyde molarity, activation time, and the interplay of activation time and the quantity of MWCNT-NH (2) -glutaraldehyde can exert a statistically significant positive impact on the enzyme's activity (p < 0.05). The combination of activation time and buffer solution molarity, as well as the interactive effect of buffer pH and MWCNT-NH2-glutaraldehyde, can lead to a significant improvement in the stabilization efficiency of the protease of carbon nanotubes. The analysis of variance results demonstrated that the efficiency of covalently immobilizing beta-galactosidase from Aspergillus oryzae on amino-functionalized multi-walled carbon nanotubes is influenced by the molarity of glutaraldehyde, buffer pH, stabilization time, and the interplay of activation time + buffer pH, buffer pH + activation time, activation time + buffer molarity, and glutaraldehyde molarity + MWCNT-NH (2) -glutaraldehyde (p < 0.05). Through the optimization and selection of optimal formulations, the obtained results indicate enzyme activities and stabilization efficiencies of 64.09 % +/- 72.63 % and 65.96 % +/- 71.77 % for protease and beta-galactosidase, respectively. Moreover, increasing the enzyme stabilization time resulted in a reduction of enzyme activity. Furthermore, an increase in pH, temperature, and the duration of milk storage passing through the enzyme-immobilized carbon nanotubes led to a decrease in enzyme stabilization efficiency, and lactose hydrolysis declined progressively over 8-h. Hence, the covalent immobilization of beta-galactosidase from Aspergillus oryzae and protease from Bacillus licheniformis onto amino-functionalized multi-walled carbon nanotubes is anticipated to be achievable for milk applications.