Thermodynamic characterization of Aspergillus flavus KP998209 xylanase, Production optimization with statistical optimization

Hashem, Amal M.; Elzairy, Nermeen H.; Mostafa, Faten A.; Hashem, Abdelgawad M.; Abdel–Naby, Mohamed A.

doi:10.21608/ejchem.2021.108800.4973

Thermodynamic characterization of Aspergillus flavus KP998209 xylanase, Production optimization with statistical optimization

Document Type : Original Article

Authors

¹ Chemistry of Natural and Microbial Products Department, National Research Centre, Dokki, Giza, 12622, Egypt.

² Department of Microbiology and Immunology, Faculty of Pharmacy, The British University, Egypt.

10.21608/ejchem.2021.108800.4973

Abstract

This study succeeded in studying the physiochemical, kinetics and thermodynamic characteristics of Aspergillus flavus KP998209 xylanase. The A. flavus xylanase production utilizing corn cobs as xylan substrate was improved through two steps statistical factorial designs namely Plackett–Burman design and Taguchi L9 (3^4) orthogonal array designs causing 1.52-fold and 2.39-fold increase, respectively in xylanase production compared to un-optimized medium. Moreover, A. flavus xylanase kinetics were determined to be 5.68 mg.ml-1 for Km, 1.715 U.mg-1 for Vmax and 73.74 S-1 for Kcat. Besides, the calculated values for oat xylan hydrolysis thermodynamics including ΔH* (13.41 kJ.mol−1), ΔG* (67.76 kJ.mol−1), ΔS* (−168.27 J.mol−1K−1), ΔG*E-S (4.665 kJ.mol−1) and ΔG*E-T (−6.88 kJ.mol−1). T1/2 (half life), Kd (Thermal deactivation constant) and D-values at 50, 55 and 60 ºC were determined to be 143.48, 68.76, 45.35 min, 4.83x10-3, 10.08x10-3, 15.28x10-3 min-1 and 476.81, 228.47, 150.71 min, respectively. Moreover, A. flavus xylanase denaturation thermodynamics including ΔHd, ΔGd and ΔSd at 50, 55 and 60 ºC emphasized its suitability for industrial applications.

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