Abstract :

The aim of this study was to optimize the medium and cultivation conditions and to investigate the possibility of applying Aureobasidium pullulans BS1 for the study of anti-oxidant activity and metal biosorption efficiency with the simultaneous biosynthesis of Pullulan. The A. pullulans BS1 was screened from the phylloplane of Brassica oleracea reported in our previous study by enrichment process. The various parameters (pH, Temperature, Time period of Incubation and types of Carbon and Nitrogen sources) were optimized. The optimal medium for pullulan production by this strain BS1 was 7.0% (w/v) glucose, 1.8% (w/v) soybean cake hydrolysate, 0.45% (w/v) K 2 HPO 4 , 0.1% (w/v) NaCl, 0.02% (w/v) MgSO 4 ?7H 2 O, 0.05% (w/v) (NH 4 ) 2 SO 4 , pH 6.5. The optimal cultivation conditions for pullulan production by this strain in 300-ml shake flask containing 50 ml of medium were observed at 28�C and with 180 rpm. Under these conditions, 6.5% (w/v) pullulan was produced within a time period of 3 days. No melanin like pigments in the medium was observed during the fermentation process, indicating that strain BS1 was a non-pigmented yeast strain. The metal absorption efficiency and the antioxidant properties of the isolated strain were found with simultaneous production of pullulan in the fermentation broth