A thermophilic and thermostable xylanase from Caldicoprobacter algeriensis: Recombinant expression, characterization and application in paper biobleaching
| Autor: | Sonia Jemli, Samir Bejar, Sawssan Neifar, Bassem Jaouadi, Monia Mezghani, Sonia Mhiri, Amel Bouanane-Darenfed, Rihab Ameri, Khelifa Bouacem |
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| Rok vydání: | 2020 |
| Předmět: |
Models
Molecular Molecular model 02 engineering and technology medicine.disease_cause Biochemistry Gene Expression Regulation Enzymologic 03 medical and health sciences Structural Biology Enzyme Stability Glycoside hydrolase family 10 Escherichia coli medicine Amino Acid Sequence Cloning Molecular Clostridium stercorarium Molecular Biology 030304 developmental biology Clostridiales 0303 health sciences Endo-1 4-beta Xylanases biology Chemistry Thermophile Temperature General Medicine 021001 nanoscience & nanotechnology biology.organism_classification Recombinant Proteins Kinetics Kraft process Xylanase Specific activity 0210 nano-technology |
| Zdroj: | International Journal of Biological Macromolecules. 164:808-817 |
| ISSN: | 0141-8130 |
| Popis: | A novel xylanase gene xynBCA, encoding a polypeptide of 439 residues (XynBCA), was cloned from Caldicoprobacter algeriensis genome and recombinantly expressed in Escherichia coli BL21(DE3). The amino acid sequence analysis showed that XynBCA belongs to the glycoside hydrolase family 10. The purified recombinant enzyme has a monomeric structure of 52 kDa. It is active and stable in a wide range of pH from 3 to 10 with a maximum activity at 6.5. Interestingly, XynBCA was highly thermoactive with an optimum temperature of 80 °C, thermostable with a half-life of 20 min at 80 °C. The specific activity was 117 U mg−1, while the Km and Vmax were 1.247 mg ml−1, and 114.7 μmol min−1 mg−1, respectively. The investigation of XynBCA in kraft pulp biobleaching experiments showed effectiveness in releasing reducing sugars and chromophores, with best achievements at 100 U g−1 of pulp and 1 h of incubation. The comparative molecular modeling studies with the less thermostable Xylanase B from Clostridium stercorarium, revealed extra charged residues at the surface of XynBCA potentially participating in the formation of intermolecular hydrogen bonds with solvent molecules or generating salt bridges, therefore contributing to the higher thermal stability. |
| Databáze: | OpenAIRE |
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