Metal-Tolerant Pseudomonas aeruginosa Strain ZM130 has the potential for concurrent dye decolorization and plant growth promotion

Dye decolorizing Pseudomonas aeruginosa strain ZM130 was characterized for its potential to decolorize reactive yellow 2 (RY2) dye as well as for its characteristics to promote plant growth under stressed conditions in the presence of a multi-metal mixture (Cr ⁶⁺ , Pb ²⁺ , Cd ²⁺ and Zn ²⁺ ). The bacterial growth and RY2 decolorization by this strain were significantly (p ≤ 0.05) increased when the multi-metal-stressed medium was enriched with yeast extract. The individual and interactive impacts of levels of NaCl, pH and concentration of yeast extract as well as the multi-metal mixture were evaluated following response surface methodology (RSM) modeling based on quadratic polynomial equations. Based on RSM data, optimal decolorization of RY2 was predicted at 14.4 g L ^-1 NaCl, 7.9 pH, 5.8 g/L yeast extract and a multi-metal mixture (Cr: 11.65 mg/L; Pb: 23.30 mg/L; Cd: 11.65 mg/L; Zn: 23.30 mg/L). This strain also showed a good potential for production of IAA (indole-3-acetic acid) and inorganic phosphorus (P) solubilization in the presence of multi-metal mixture and RY2. Assessment of plant growth promotion in a pot study indicated that the strain ZM130 had the potential to significantly enhance the growth of maize (Zea mays) in normal soil as well as the soil contaminated with multi-metal mixture and RY2. On the basis of its multifarious characteristics, the strain ZM130 is envisaged as a potential bioinoculant to devise the strategies for integrated bioremediation and plant growth promotion in agricultural soils contaminated with textile wastewaters.