Characterization of pectin degrading polygalacturonase produced by Bacillus licheniformis KIBGE-IB21

A commercially available pectin degrading enzyme preparation is not usually pure and may contain several other auxiliary enzymes including pectin lyase and pectin methyl esterase with reasonably trace quantities of cellulases as well. Current work is focused to characterize an industrially important pectin degrading enzyme known as polygalacturonase produced by Bacillus licheniformis KIBGE-IB21 in term of its catalytic activity. The enzyme showed maximum activity when it was incubated for 05 min at 45 °C in an alkaline pH environment of pH-10.0. This enzyme is stable at a broad pH range and retained almost 100% of its initial activity in between pH 8.0 and 10.0 after 60 min. It also exhibited high stability against different temperatures and 100% residual activity was measured at 30 °C and 40 °C up to 1 h. The apparent Km and Vmax values for pectin degradation were 1.017 mg ml−1 and 23,800 μM min−1, respectively with an approximate molecular weight of 153 kDa. Polygalacturonase also demonstrated exceptional storage stability at ˗20 °C even after 30 days.