10.22376/ijpbs.2019.10.1.p1-12 Volume 6 Issue 4 2015 (October - December) The present investigation lessThan i greaterThan Allochromatium lessThan /i greaterThan sp. GSKRLMBKU-01, lessThan i greaterThan Rhodobacter lessThan /i greaterThan sp. GSKRLMBKU-02 and lessThan i greaterThan Rhodobacter lessThan /i greaterThan sp. GSKRLMBKU-03 were isolated from different ecological niches and its ability to produce Indole Acetic Acid (IAA) in the presence and absence of tryptophan as inducer was investigated. All the three bacteria produce IAA even in the absence and presence of tryptophan but production was more in tryptophan supplemented medium. The maximum IAA production by lessThan i greaterThan Allochromatium lessThan /i greaterThan sp. GSKRLMBKU-01 (165 μg/ml), lessThan i greaterThan Rhodobacter lessThan /i greaterThan sp. GSKRLMBKU-02 (140 μg/ml) and lessThan i greaterThan Rhodobacter lessThan /i greaterThan sp. GSKRLMBKU-03 (120 μg/ml) was recorded. The highest amount of biomass and IAA production was recorded on 8 lessThan sup greaterThan th lessThan /sup greaterThan day of incubation by lessThan i greaterThan Allochromatium lessThan /i greaterThan sp. GSKRLMBKU-01 and lessThan i greaterThan Rhodobacter lessThan /i greaterThan sp. GSKRLMBKU-03, while lessThan i greaterThan Rhodobacter lessThan /i greaterThan sp. GSKRLMBKU-02 was recorded on 10 lessThan sup greaterThan th lessThan /sup greaterThan day of incubation. KADARI RAJYALAXM AND SIVADEVUNI GIRISHAM Anoxygenic phototrophic purple bacteria, Allochromatium sp., Rhodobacter sp., Biomass and Indole acetic acid. 274-278