The indoleacetic acid (IAA) is a natural auxin and one of the main growth regulators in higher plants. The extracellular indoleacetic acid (IAA) amount produced by the green microalga Scenedesmus obliquus culture was detected by high performance liquid chromatography (HPLC). It was evaluated the effect of three process variables in the extracellular IAA production in these cultures using 2³ factorial design for screening methodology. The experimental design variables were agitation, illuminance (intensity of luminous flux) and carbon source (CO2/air v/v (%) mixture) at three different levels. The IAA concentration and the specific growth rate were used as response variables. The HPLC analyses showed that under experimental conditions, the IAA amount that is released to the medium by S. obliquus depends only on the illuminance variable. The light effects and the carbon concentrations in culture medium were significant (p < 0.05) for specific growth rate.
indoleacetic acid; green microalgae; HPLC; Scenedesmus obliquus
