OPTIMIZATION OF ANTIBIOTIC PRODUCTION BY THE CYANOBACTERIUM SCYTONEMASP TISTR-8208 IMMOBILIZED ON POLYURETHANE FOAM

The cyanobacterium Scytonema sp. TISTR 8208 was cultivated under illum ination with a polyurethane foam sheet as the biomass-supporting mater ial. The cyanobacterium produced an antibiotic with a broad spectrum i n the post-exponential phase of growth. Modification of the compositio n of the BGA medium by adding 1.5 gl(-1) NaNO3, increasing the Fe-2(SO 4)(3).6H(2)O concentration to 0.025 gl(-1), not adding NaCl, using an initial pH of 7.0, incubated at 35 degrees C, and at the light intensi ty of 90 mu mol photon m(-2) s(-1), enabled a 28-fold increase in anti biotic production. The antibiotic was stable when treated at 70 degree s C for 2h and unstable at 100 degrees C for 75 min. Since the activit y was completely lost with protease treatment and the positive result was shown toward ninhydrin test, and the UV and IR spectrum were chara cterized at 210 nm and 1547 cm(-1), respectively, this antibiotic appe ars to be a peptide with aromatic amino acid. Analysis by double-focus ing mass spectrometry showed the molecular weight of the antibiotic to be 1490.