Improvement of optimum pH and specific activity of pectate lyase from Bacillus RN.1 using loop replacement

Background: Alkaline pectate lyase plays an important role in papermaking, biological refining and wastewater treatment, but its industrial applications are largely limited owing to low activity poor alkali resistance. Methods: The alkaline BspPel from Bacillus RN.1 was heterologously expressed Escherichia coli BL21 (DE3) resistance were improved by loop replacement. Simultaneously, the effect of R260 on enzyme tolerance also explored. Results: Recombinant (BspPel-th) showed highest at 60°C pH 11.0, significant stability over a wide range (3.0–11.0). specific after purification 139.4 U/mg, which 4.4 times higher than that wild-type enzyme. BspPel-th has good affinity for apple pectin, since V max K m 29 μmol/min. mL 0.46 mol/L, respectively. Molecular dynamics simulation results flexibility region improved. Conclusion: modified considerable potential with high processes.