The novel benzoxazolophenanthridine
antibiotic,
jadomycin B, is produced by Streptomyces venezuelae ISP5230 following a 42 degrees C heat shock or exposure to
ethanol. To further characterize these unusual culture conditions, studies were carried out using different media, varying nutrient content and concentrations, initial pH, and time of application of heat or
ethanol stress. Highest titers of
jadomycin B accumulated 48 h after S. venezuelae ISP5230 was inoculated into a
D-galactose-
L-isoleucine production medium (pH 7.5) which was supplemented with
ethanol (6%, v/v) between 6 and 13 h. Cultures supplemented with
ethanol later than 17 h post inoculation into the production medium produced little or no
jadomycin B. Among other heat-shock inducing treatments examined,
infection with phage SV1 was associated with increased
jadomycin B production. Although
jadomycin B titers showed little change with variations in the concentration of
phosphate in the production medium, the nature of the
nitrogen source was found to be important. Different colored pigments, presumed to be
jadomycin B analogs, were formed when other
amino acids replaced
L-isoleucine in the medium as the sole
nitrogen source. Increased
jadomycin B titers accompanied increased
L-isoleucine and
D-galactose concentrations in the production medium.