Optimal production of a novel endo-acting β-1,4-xylanase cloned from Saccharophagus degradans 2-40 into Escherichia coli BL21(DE3)

To date, gene xyn10C from Saccharophagus degradans 2-40 has only been identified to encode a potential xylanase. In the present study, xyn10C was cloned and overexpressed in Escherichia coli BL21(DE3). The protein produced by xyn10C, Xyn10C, was expressed in a soluble active form and found to be an endotype β-1,4-xylanase that preferentially produces xylobiose from xylan. Recombinant cell fermentation revealed that induction of the gene at low temperatures fostered expression of the recombinant xylanase with high volumetric and specific activities. Additionally, low growth rates were favorable for producing soluble active xylanase via a reduction in the formation of inclusion bodies. Furthermore, the optimal concentration of isopropyl-β-D-thiogalactopyranoside for induction was found to be 100 μm after two hours of precultivation at 37°C. Finally, enzyme production conducted using a fermentor with a working volume of 1.5-l resulted in slightly higher specific activities of xylanase when compared with the generation of enzymes in flasks with a working volume of 100 ml.