Synergistic phytoremediation strategy for textile effluent contaminated soil reclamation using Sesuvium...

Textile industries produce highly saline and chemically complex effluents that severely degrade soil quality and limit plant growth. This study assessed the phytodesalination capability of the halophyte Sesuvium portulacastrum, both independently and in conjunction with the halotolerant plant growth-promoting rhizobacterium Bacillus megaterium (OPS2), for the reclamation of saline soils contaminated by textile effluent in Tirupur District, Tamil Nadu, India. S. portulacastrum collected from Pichavaram tolerated salinity levels up to 5000 mg kg⁻¹ NaCl and accumulated sodium up to 4.4% in plant tissues, demonstrating strong salt hyperaccumulation capacity. Among 25 rhizosphere bacterial isolates screened, B. megaterium (OPS2) exhibited superior salt tolerance (growth up to 3% NaCl) and notable plant growth-promoting traits, including indole-3-acetic acid production (18.5 µg mL⁻¹), siderophore secretion, and phosphate solubilization. Pot culture experiments revealed that the combined application of S. portulacastrum, vermicompost (5 t ha⁻¹), and PGPR reduced soil electrical conductivity (EC) from 10.1 to 2.8 dS m⁻¹ and sodium concentration from 3095 to 610 mg kg⁻¹ within 60 days. Field trials further confirmed these results, showing a decrease in soil EC from 13.5 to 3.2 dS m⁻¹ and sodium from 3500 to 700 mg kg⁻¹ over the same period. Moreover, PGPR inoculation significantly enhanced the biomass of S. portulacastrum, which reached 475 g plant⁻¹ under field conditions. These findings highlight the synergistic potential of S. portulacastrum and B. megaterium-based bioaugmentation as an effective, sustainable strategy for the rapid reclamation of effluent-contaminated saline soils.