摘要：Various media parameters affecting the polygalacturonase (PG) production of Rhizopus oryzae, were studied and their relation to pellet morphology was investigated. The basal medium in the absence of Mg+2 and in the presence of 4 mg/kg of Zn +2 at pH 3, resulted into maximum PG activity (11.53 U/ml). A composition of 14.78 g/l of glucose, 10 g/l of galactose, 5 g/l mannose, 0.5 g/l of arabinose and 19.73 g/l of xylose resulted into maximum PG activity (27.94 U/ml) when used as combined carbon sources. Corn meal as the nitrogen source, promoted PG synthesis where it resulted into 33 % more activity than corn steep liquor (CSL) and (NH4)2SO4 which were the next highest promoter. The highest number of pellets with an average mean diameter of 1.25±0.25 mm was obtained with the formulation containing (NH4)2SO4 and 25 g/l of glucose. Yeast extract on the other hand resulted into pellet formation with an average mean diameter of 1.75±0.25 mm at higher glucose concentration (50 g/l). The interactive effect of suitable carbon source (glucose) with suitable nitrogen source (corn meal) enhanced the PG activity 4 times more than the basal medium with pellets of 1.44±0.35mm in average diameter.
