[Effect of the carbon/nitrogen ratio on the antibiotic activity of prodigiosin].

The antibacterical activity of prodigiosin varies according to the C/N ratio in the cultural media for S. marcescens. In organic media, as nutrient agar, peptone or soytone, the optimal ratio lies between 4 and 5, and higher values are required for "mineral media" where the nitrogen source is essentially an ammonium salt. The separate C source would be probably used as "acetate source" for the synthesis of the terminal alkylpyrrole.