Isolation and Characterization of Polygalacturonase Produced by Tetracoccosporium sp.

Thirty-five fungal strains which isolated from vegetable wastes, were screened for the use of polygalacturonic acid as the sole carbon source. Twenty-five isolates were positive for polygalacturonase activity in cup-plate assay, as evidenced by clear hydrolysation zones. The most productive strain was determined by measuring clear zones formed around colonies stained with ruthenium red. The highly pectinolytic fungal strain was tentatively identified as Tetraoccosporium sp. according to morphological characterization. The cultivation of the selected strain (Tetracoccosporiumsp.) in liquid media resulted in high quantities of polygalacturonase enzyme. Maximum polygalacturonase activity was reached in 48 h of growth in the pectate medium. The collected polygalacturonase had optimum activity at pH 5.0 and maximal activity of the enzyme was determined at 35 °C. Mn2+, Ag3+and surface active detergents such as tween 20 and triton X-100 increased the polygalacturonase activity by 37 % and EDTA enhanced the activity up to 125 %.