The aim of this study was to isolate endophytic bacteria from Mimosa pigra and to screen of indole-3-acetic acid (IAA) production activity. A total 36 isolates of endophytic bacteria were obtained. These endophytes were evaluated for IAA production by colorimetric method. Aeromonas jandaei isolated from the part of stem showed the highest activity. This bacterium produced IAA at the concentration of 8.6 µg/ml in Tryptic Soy Broth (TSB) containing 200 µg/ml of L-tryptophan while 35 other isolates produced IAA in the range of 0.6 to 5.0 µg/ml. Further investigations were carried out for the effects of shaking and tryptophan concentration on IAA production by A. jandaei. The production of IAA by A. jandaei under shaking condition increased up to 11 fold over static. IAA production of A. jandaei was increased when the concentration of tryptophan in TSB medium was increased from 200 to 1,200 µg/ml. In the presence of 1,200 µg/ml of tryptophan, A. jandaei produced IAA at the concentration of 48.7 µg/ml. This study is the first report of IAA production by A. jandaei isolated from M. pigra.
Burapha University International Conference 2015