Optimization of indole-3-acetic acid (IAA) production by rhizobacteria isolated from epiphytic orchids

Abstract

The optimal conditions for indole-3-acetic acid (IAA) production by bacterial isolate DPY-05 (Gram-positive, rods), living in association with aerial orchid roots (Dendrobium pulchellum) were studied. The factors that affect the IAA production were investigated including culture media, pH, temperature, agitation and culture period. The results showed that the isolated DPY-05 gave the highest amount of IAA of 67.18 ?g/ml when cultured in King-B medium supplemented with tryptophan 2.5 mM (KB+Trp) pH 7.0 at 37oC in static condition for 6 days.