Characterization of a fusion enzyme tCel5A1-XynZC having enhanced activity on plant biomass

A fusion construct of the genes encoding a truncated version of Cel5A (tCel5A1) from Thermotoga maritima and catalytic domain of XynZ (XynZC) from Clostridium thermocellum, was expressed in E. coli BL21 CodonPlus (RIPL) cells. Comparison of activities of tCel5A1-XynZC thus produced with the individual enzymes showed 1.0 to 2.0 fold increased activity against carboxymethyl cellulose, and 1.35 fold increased activity against Beechwood xylan. Increase in activity was 1.2, 1.0, 1.8, and 1.6 fold against regenerated amorphous cellulose, Avicel, wheat straw and rice straw, respectively. Optimum temperature and pH of tCel5A1-XynZC was found to be 60 °C and 6.0, respectively. Fusion protein was thermostable at 60 °C for 2 h. Therefore, bifunctional tCel5A1-XynZC can be a useful candidate for industrial applications due to its high activity and thermostability.