Indole-3-butyric acid (IBA) production in culture medium by wild strain Azospirillum brasilense.

Some microorganisms found in the soil are able to produce substances which regulate plant growth. In this study, we show the presence of a substance associated with auxin activity, identified as indole-3-butyric acid (IBA), in Azospirillum brasilense UAP 154 growth medium. A. brasilense was grown and indolic compounds were extracted from the supernatant. These were then analyzed by high performance liquid chromatography (HPLC), gas chromatography and gas chromatography mass spectrometry. The retention time was similar to those of the authentic IBA standard. The compound obtained from HPLC was collected and applied to maize seedlings (Zea mays), inducing biological activity along the roots, similar to that induced by an authentic IBA standard.