Isolation, Screening and Identification of Indole Acetic Acid (IAA) Producing Bacteria from Rhizospheric Soil

Pranita Malankar, Manish Petkar

Abstract: A total of 14 bacterial strains were isolated from rhizospheric soil collected from Koparkhairane, Navi Mumbai, India. All isolates were screened primarily for their potential to produce indole acetic acid (IAA) using L-tryptophan as a substrate. Subsequently, in secondary screening, strain P2C11 was found to be a potent IAA producer based on the IAA concentration produced by all the isolates. Further, the isolate P2C11 was analyzed by MALDI-TOF & 16S rRNA sequencing and it was identified as Microbacterium hydrocarbonoxydans. It produced 290 g/ml IAA which is higher than the reported IAA production by this genus. L-tryptophan and IAA analysis was done using High Performance Liquid Chromatography (HPLC). Confirmation of IAA production in fermentation broth was done by Gas Chromatography-Mass Spectrometry (GC-MS). The isolate P2C11 was found to have the potential to be used as an efficient bio-fertilizer inoculant to promote growth of economically and agriculturally valuable plants.

Keywords: Indole acetic acid, L-tryptophan, PGPR, Microbacterium hydrocarboxydans, Microbial characterization