Improved secretory expression and characterization of thermostable xylanase and β-xylosidase from Pseudothermotoga thermarum and their application in synergistic degradation of lignocellulose

Xylanase and β -xylosidase are the key enzymes for hemicellulose hydrolysis. To further improve hydrolysis efficacy, high temperature with thermostable hemicellulases showed promise. In this study, xylanase (Xyn) (XynB) genes from Pseudothermotoga thermarum were cloned secretory expressed in Bacillu subtilis . Compared Escherichia coli expression host, B. resulted a 1.5 time increase of enzymatic activity both recombinant enzymes. The optimal pH 95°C 6.5 Xyn, 6.0 XynB. Thermostability was observed between range 75–85°C. Molecular docking analysis through AutoDock involvement Glu525, Asn526, Trp774 Arg784 Xyn-ligand interaction, Val237, Lys238, Val761 Asn76 XynB-ligand respectively. Xyn XynB exhibited synergistic beechwood xylan pretreated lignocellulose, where pre-hydrolysis achieved better improvement lignocellulose by commercial cellulase. stability at effect on lignocellulosic substrates suggested possible application these field saccharification process.