International Journal of Biochemistry and Biophysics Vol. 6(2), pp. 44 - 57
DOI: 10.13189/ijbb.2018.060203
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Parameters Affecting the Improvement of Properties and Stabilities of Immobilized α-amylase on Chitosan-metal Oxide Composites

V. U. Bindu , A. A. Shanty , P. V. Mohanan ^*
Department of Applied Chemistry, Cochin University of Science and Technology, India

ABSTRACT

Chitosan-metal oxide composites, chitosan- Fe₃O₄ (CSM) and chitosan-ZnO (CSZ) were synthesized and intended as suitable supports for immobilization of starch hydrolyzing enzyme, α-amylase. Here α-amylase was chosen as the enzyme to immobilize on these supports due to its wide implementation in industrial applications. The immobilized enzyme, CSZE showed better immobilization yield of 76%, whereas CSME provides high speed and easy separation from the reaction system due to its magnetic property. The quality of the immobilized α-amylases was demonstrated and assessed based on its activity and stability. The immobilized enzymes with higher Ed values provide them more stability towards denaturation compared to free enzyme. At 50℃ the thermodynamic parameters such as ∆H^º, ∆G^º and ∆S^º for thermal deactivation of free enzyme were evaluated as 104.29, 12.83 and -0.28 KJ mol^-1 respectively and are found to be higher in case of both immobilized enzymes. The Km values for CSME and CSZE are 0.65 and 0.5mg/mL respectively, which are higher than that of free enzyme (0.45mg/mL). The Vmax of free enzyme is decreased from 34.48μmol mg^-1 min^-1 to 16.39(CSME) and 23.81 (CSZE) μmol mg^-1 min^-1 as a result of immobilization. The immobilized enzymes have exhibited better storage stability over 6 months and retained more than 50% of their initial activities after 10 cycles of reuses.

KEYWORDS
Chitosan-metal Oxide Composite, α-Amylase, Immobilization, Thermal Deactivation, Catalytic Activity, Maltose

Cite This Paper in IEEE or APA Citation Styles
(a). IEEE Format:
[1] V. U. Bindu , A. A. Shanty , P. V. Mohanan , "Parameters Affecting the Improvement of Properties and Stabilities of Immobilized α-amylase on Chitosan-metal Oxide Composites," International Journal of Biochemistry and Biophysics, Vol. 6, No. 2, pp. 44 - 57, 2018. DOI: 10.13189/ijbb.2018.060203.

(b). APA Format:
V. U. Bindu , A. A. Shanty , P. V. Mohanan (2018). Parameters Affecting the Improvement of Properties and Stabilities of Immobilized α-amylase on Chitosan-metal Oxide Composites. International Journal of Biochemistry and Biophysics, 6(2), 44 - 57. DOI: 10.13189/ijbb.2018.060203.