The effect of environmental factors on surfactin production of Bacillus subtilis

Abstract

Surfactin is one of the most efficient biosurfactants excreted by Bacillus subtilis which displays the highest potential as induced systemic resistance elicitor among all metabolites produced by B. subtilis. Environmental factors have considerable effect on surfactin production. In this study surfactin production of two Bacillus subtilis strains were analyzed using high performance liquid chromatography (HPLC). C14 and C15 surfactins were detected in the ethanol extract from acid-precipitated supernatant. HPLC analyses of different media including Nutrient Broth (NB) medium, NB plus 40g/l glucose, NB plus 10% soil extract and NB plus 10% plant extract medium, clearly showed that these bacteria produced different amounts of surfactins C14 and C15 in these media. Surfactin production in NB/plant medium was relatively the highest in quantity. Microelements analysis of media containing plant and soil extract with atomic absorption spectrometry showed high amounts of Fe, Mn and Zn in medium containing plant extract compared with that of soil extract. Since these elements play an important role in surfactin production, high amounts of Fe, Mn and Zn in NB/plant extract medium compared to the NB/soil extract medium could be the possible reason for relatively higher amounts of surfactins C14 and C15 produced in NB/plant medium. So adding these important elements to soil may boost biocontrol effect of B. subtilis against plant pathogens.

Keywords

• surfactin
• hplc
• bacillus spp
• biocontrol