Covalent Immobilization of Dothideomycetes sp. NRC-SSW Chitosanase and Its Application in Chitosan Hydrolysis

Ismail, Shaymaa; Ismail, Siham; Hassan, Mohamed El Sayed; Hosny, Alaa El-Dein; Hashem, Amal Mohamed

doi:10.21608/ejchem.2021.80642.4000

Covalent Immobilization of Dothideomycetes sp. NRC-SSW Chitosanase and Its Application in Chitosan Hydrolysis

Document Type : Original Article

Authors

¹ Department of Chemistry of Natural and Microbial Products, Division of Pharmaceutical and Drug Industries, National Research Centre, Cairo, Egypt.

² Chemistry of Natural and Microbial Products Department, National Research Centre, Dokki, Giza, Egypt.

³ Center of Excellence, Encapsulation &amp; Nano biotechnology Group, Chemistry of Natural and Microbial Products Department, National Research Center, El Behouth Street, Cairo 12622, Egypt.

⁴ microbiology department, faculty of pharmacy, Cairo university, Cairo, Egypt.

10.21608/ejchem.2021.80642.4000

Abstract

Chitosanases are chitosan specific glycosyl hydrolases that can exploit in several biotechnological applications. In the current study, a modified bead of carrageenan and carboxymethyl cellulose was used for the covalent immobilization of Dothideomycetes sp. NRC-SSW chitosanase. The immobilization process was optimized and the immobilization recovery was increased up to 69%. The stepwise different bead formulations were examined under Scanning Electron Microscope, Fourier Transform Infrared Spectroscopy and Thermal Gravimetric analysis, confirming the success of the immobilization process. Additionally different properties including enzyme storage, thermal and pH stabilities were examined and an improvement in all of these properties was estimated. Although the same Vmax value (23.8U/min/mg protein) was recorded for the free and the immobilized enzymes, the Km was 10mg chitosan/ml and 16.67mg chitosan/ml for the immobilized and free form respectively. The activation energy for chitosan hydrolysis using the immobilized enzyme (12.497kJmol−1) was less than the third of that recorded for the free one (42.196kJmol−1). Furthermore, the immobilized enzyme was stable until the 5th cycle at which it retained more than 50% of its original activity. All the tested parameters confirmed that the immobilized Dothideomycetes sp. NRC-SSW chitosanase was more applicable for chitosan hydrolysis than the native enzyme.

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