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A thermophilic and thermostable xylanase from Caldicoprobacter algeriensis: Recombinant expression, characterization and application in paper biobleaching
- Source :
- International Journal of Biological Macromolecules. 164:808-817
- Publication Year :
- 2020
- Publisher :
- Elsevier BV, 2020.
-
Abstract
- 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.
- Subjects :
- 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
Subjects
Details
- ISSN :
- 01418130
- Volume :
- 164
- Database :
- OpenAIRE
- Journal :
- International Journal of Biological Macromolecules
- Accession number :
- edsair.doi.dedup.....7bcb9856a3b58ecb6a78bb6e8f6d115e