Characterization of Pink-Pigmented Facultative Methylotrophs (Ppfm) isolated from paddy leaf (Oryza Sativa)

Methylobacterium sp. is pink-pigmented facultative methylotrophs (PPFMs) that have the ability to promote the growth of plants and is ubiquitous in the environment. Methylobacterium sp. is able to utilise methanol as its energy source. Five strains of Methylobacterium sp. which were isolated from paddy leaf (Oryza sativa) were tested for the plant growth promoting characteristics. They were grown in Ammonia Mineral Salt (AMS) agar throughout the experiment and supplemented with methanol as a carbon source. L-tryptophan was used as a precursor for production of indole acetic acid. The indole acetic acid production of were done with several concentrations of L-tryptophan and isolate EPPD1 (0.061) showed the highest production if indole acetic acid in the presence of L-tryptophan. When Methylobacterium sp. isolates tested for nitrogen fixing ability, all the isolates did not showed promising results except for EPPD4. In phosphate solubilising ability, EPPD4 and ENPD2 recorded good result when using Solubilising Index (SI) but when the isolates were assayed for phosphate solubilisation using vanadate-molybdate reagent, all of the isolates showed promising findings especially ENPD2 is the highest in National Botanical Research Institute Phosphate (NBRIP) broth and second highest solubilisation in Pikovskaya broth while EPPD1 is the highest in Pikovskaya broth. Thus, the Methylobacterium sp. strains that analysed had a promising ability to be develop as a bio-fertiliser for a sustainable environment.