title: Covalent immobilization of Enterococcus faecalis Esawy dextransucrase and dextran synthesis.
abstract: Enterococcus faecalis Esawy dextransucrase was immobilized in Fe(3+)-cross-linked alginate/carboxymethyl cellulose (AC) beads. The gel beads were modified with polyethylenimine (PEI) followed by glutaraldehyde (GA) to form Fe(3+) (ACPG) beads. Fe(3+) (ACPG) was characterized using FTIR and DSC techniques. GA activated beads showed new two peaks. The first was at 1,717 cm(-1) which refers to (CO) group of a free aldehyde end of glutaraldehyde, and another peak was at 1,660 cm(-1) referring to (CN) group. The immobilization process improved the optimum temperature from 35 to 45°C. The immobilized enzyme showed its optimum activity in wide pH range (4.5-5.4) compared to pH 5.4 in case of free form. Also, the immobilization process improved the thermal and pH enzyme stability to great extent. Reusability test proved that the enzyme activity retained 60% after 15 batch reactions. Immobilized enzyme was applied successfully in the synthesis of oligosaccharides and different molecular weights of dextran.
authors.affiliation: Department of Chemistry of Microbial and Natural Products, National Research Centre (NRC), Dokki, Cairo, Egypt.
authors.forename: Amal M
authors.initials: AM
authors.lastname: Hashem
authors.affiliation: Department of Chemistry of Microbial and Natural Products, National Research Centre (NRC), Dokki, Cairo, Egypt.
authors.forename: Amira A
authors.initials: AA
authors.lastname: Gamal
authors.affiliation: Center of Excellence, Encapsulation & Nanobiotechnology Group, National Research Center, Egypt.
authors.forename: Mohamed E
authors.initials: ME
authors.lastname: Hassan
authors.affiliation: Department of Microbiology, Faculty of Science, Ain Shams University, Cairo, Egypt.
authors.forename: Naziha M
authors.initials: NM
authors.lastname: Hassanein
authors.affiliation: Department of Chemistry of Microbial and Natural Products, National Research Centre (NRC), Dokki, Cairo, Egypt. Electronic address: mona_esawy@hotmail.com.
authors.forename: Mona A
authors.initials: MA
authors.lastname: Esawy
mesh_terms: D003911:Dextrans / Q000138:chemical synthesis / Q000737:chemistry*; D013293:Enterococcus faecalis / Q000201:enzymology* / Q000302:isolation & purification; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D005964:Glucosyltransferases / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008863:Microspheres; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013816:Thermodynamics
chemical_list: D003911:Dextrans; D004800:Enzymes, Immobilized; D005964:Glucosyltransferases; C020025:dextransucrase
keywords: Covalent binding; Dextran; Dextransucrase; Enterococcus faecalis; Immobilization; Oligosaccharides