Extraction of a polygalacturonase from Macrophomiona phaseolina and analysis of its stability

Polygalacturonases (GH28) hydrolyze the pectic substances, present mostly in plants. Polygalacturonases are widely distributed among some bacteria, fungi, and higher plants. Microbial polygalacturonases, mainly produced by fungi, are utilized in many large-scale industrial processes. Production of a polygalacturonase from a fungal phytopathogen, M. phaseolina was evaluated in this study. M. phaseolina was cultured in the production medium. The crude extract was separated from fungal cells. The highest enzyme activity was observed at 60 °C. This enzyme had a high stability at wide ranges of pH and temperature and exhibited a t1/2 of 400 min at 70 °C. The value for free energy of the heat inactivation at the temperature of 70 °C was about 108 kJ, suggesting its potential to be used as an industrial enzyme. Analysis of biochemical characteristics of polygalacturonase from different fungi using ProtParam demonstrated that the M. phaseolina polygalacturonase was amongst the most stable fungal polygalacturonases.