Studies on the asparaginolytic activity of the brown-pigmented streptomycetes

ABSTRACT

Twenty-eight brown-pigmented streptomycetes were isolated from different fertile Egyptian soils. Screening was carried out according to their asparaginolytic activity under static culture condition on glycerol- L-asparagine [GA] medium. Results revealed that FS-39 isolate gave the highest asparaginolytic activity. Therefore, it was selected and subjected to complete identification. The cultural, morphological and physiological characteristics of this isolate indicated that it belongs to Streptomyces phaeochromogenes. The effects of nutritional and environmental conditions on the asparaginase activity of Streptomyces phaeochromogenes FS-39 were studied. Data revealed that the maximal, yield of L-asparaginase from this strain can be obtained by growing it on glycerol-L-asparagine yeast extract [GAY] medium containing [w/v] 2.0% Glycerol, 0.2% L-asparagine, 0.1% yeast extract, 0.1% K[2]HPO[4].3H20, 0.0001% FeSO[4].7H[2]0, 0.0001% MnCl[2]. 4H[2]0, 0.0001% ZnSO[4].7H[2]O which was initially adjusted to pH 7.0, inoculated by 2% [v/v] of homogenized spore suspension [containing approximately 3.2x10[7] spores/ml] of 3 days old culture on starch nitrate medimi and incubated at 30°C for 7 days under static culture condition