Archives of microbiology: screening of pectinase-producing bacteria from citrus peel and characterization of a recombinant pectate lyase with applied potential

摘要

Pectinase is widely used in numerous industrial fields, including the food, wine, and paper industries. In this work, seven bacteria were isolated from orange peel and their pectinase production activity was assayed. One bacterium (OR-B2) identified as a Bacillus sp. showed the highest enzyme activity towards others. A gene encoding a pectate lyase designed as PelB-B2 in this work was amplified and heterogeneous expressed in E.coli. PelB-B2 was defined as a member of the PelB pectate lyase family after phylogenic tree analysis. 3D model of PelB-B2 was constructed by SWISS-MODEL and PelB-B2 showed conserved para-beta structure. After inducing culture and purified by Ni-affinity chromatography, the properties of the purified PelB-B2 were assayed. Optimal pH and temperature for PelB-B2 was pH 8.0 and 50 degrees C, respectively. PelB-B2 showed excellent pH stability and thermostability. It was stable within pH range 3.0-11.0 and retained more than 51% activity after incubation at 40 degrees C, 50 degrees C, or 60 degrees C for 1 h. Furthermore, we determined that PelB-B2 was a Ca2+-dependent pectinase and the pectin extracted from citrus was the benefit substrate for PelB-B2. The K-m and V-max of PelB-B2 were 1.64 g/L and 232.56 mol/(L min), respectively. The OR-B2 can be a new resource for pectinase production and the PelB-B2 has potential for industrial application.