Characterization of Rhizospheric Bacillus Strains SG36 and SG42 for Decolorization of Reactive Yellow 2 Dye and Vigna radiata Growth Promotion in Dye Contaminated Soil

Contamination of agricultural soils with textile wastewaters loaded with synthetic dyes is one of the emerging issues because the presence of dyes in the soils not only affects the biological characteristics of the soils but also the germination and productivity of agricultural crops. The present study reports the characterization of two multifunctional bacterial strains Bacillus sp. SG36 and Bacillus sp. SG42, which have the potential not to promote the growth of plants in soil under stress due to reactive yellow 2 (RY2) dye but also the capability to cope with this dye through its decolorization. The strains were isolated from a rhizospheric soil repeatedly contaminated with colored textile wastewaters. Both the strains had optimal RY2 decolorization potential at slightly alkaline pH (7.5) and even in the presence of significant amount of NaCl (50 g L-1 ) in the medium. The strains harbor the phosphorus solubilization and indole acetic acid production potentials in concurrence with decolorization of RY2. In a pot experiment, the strains SG36 and SG42 were found to significantly promote the growth (Shoot/root length, shoot/root fresh weight) of mung bean (Vigna radiate) in non-contaminated and RY2 contaminated soils in parallel with RY2 decolorization in the soil.