Growth phases of some antibiotics producing streptomyces and their identification

الملخص EN

The growth phases of five cultures of antibiotic producing Streptomyces isolated from western region, Saudi Arabia were studied special reference to their potentiality to excrete antibiotics.

It was found that these organisms grew exponentially during the first 4 to 7 days of incubation.

The highest specific growth rate was observed in the case of Streptomyces MY18 being 0.48 day"1 (1.44 days doubling time).

This isolate also showed the highest inhibition zone against Staph, aureus as compared with the other four Streptomyces isolates.

This antagonistic effect was more pronounced at the last five days of incubation (stationary phase).

Morphological, cultural and physiological properties of most active antibiotic producers revealed that Streptomyces MY18 and Streptomyces MR 13 are strains of 5.

aureofaciens and 5.

reseviolaceus respectively.