OPTIMIZATION OF CULTURE CONDITIONS FOR INDOLE-3-PYRUVIC ACID PRODUCTION BY STREPTOMYCES-GRISEOFLAVUS

Thirty strains of actinomycetes were isolated from fertile soils in Eg ypt on starch-nitrate agar. The isolated organisms were recognized as spore formers with aerial mycelia containing L-DAP (diaminopimelic aci d) and glycine. The inability of the vegetative mycelia to fragment in to bacillary or coccoid forms and the presence of spores borne on spor ophores, placed these organisms in the family Streptomycetaceae. The i solates also proved to be aerobic and Gram positive. The absence of DL -DAP and the presence of L-DAP in their cell hydrolysates, and the pro duction of a wide range of pigments in the aerial and substrate myceli a, assigned these isolates to the genus Streptomyces. Tne isolated org anisms were screened for production of plant growth regulators, and th e most active producer of indole-3-pyruvic acid was examined further. Using the described morphological, physiological, and biochemical crit eria for identification, this organism was identified as Streptomyces griseoflavus. The optimal culture conditions for maximal production of both cellular and extracellular indole-3-pyruvic acid by S. griseofla vus were investigated and shown to be as follows: a culture medium com posed of(g 100 mL(-1)) NH4HO3, 0.55; DL-tryptophan, 0.4; NaCl, 0.7; at pH 7 (buffered); with an incubation period of 6 days at 28 degrees C in the dark and under shaking conditions.