An Isolate of Bacillus clausii Appears to Possess Four Distinct Pectinolytic Activities

For the bacterial source, Koyulhisar (Sivas, Turkey) apple orchard soil samples were used. Obtained isolates were identified at the species level by partial protein- and 16S rRNA gene sequence homology All of them were determined to be Bacillus clausii. Cultures were prepared with these isolates and after removing the cells, the proteins in the upper fluid were precipitated with the help of an organic solvent. While performing pectinase screening, it was noticed that an existing protease digested other proteins. This proteolytic activity was eliminated by increasing the incubation temperature to 55oC. Four different pectinase activities, polygalacturonase, pectin lyase, pectate lyase, and pectin methylesterase, were then demonstrated. Four protein bands corresponding to these activities visualised by SDS-PAGE were 80 kDa, 58 kDa, 46 kDa and ~ 28 kDa, respectively. Spectroscopic methods were employed for the identification of the enzymes. The smallest protein band (28 kDa) was found to be pectin methylesterase. Km and Vmax values of this enzyme were 0.4 and 217U, respectively.