Efficacy of Phytoremediation for Methylparaben Removal from Contaminated Water: A study by Alternanthera spp and Associated Rhizobacteria

Abstract

Abstract In the present study, the potential of Alternanthera spp and its associated rhizobacteria to uptake and biodegrade methylparaben (MP) under hydroponic conditions was assessed. The experiments were conducted in vitro using glass reactors of 500-mL volume. The results indicated that the removal rates in hydroponic reactors were significantly higher (66.6±3%) than that of control reactors (<40%). MP reduction data fitted well a first-order kinetics model (R2>0.9). The presence of plants shortened the half-life (T1/2) of MP in aqueous solutions to 3.41 days compared to 34.8 days in control reactors. Bioconcentration factors (BCFs) of MP were higher for roots (1.9-5.2 L/kg) compared to stems (0-0.5 L/kg). High-tolerant rhizobacteria for MP were isolated from the roots of Alternanthera spp and characterized. It was shown that three isolates achieved noticeable efficiencies in removing MP in a separated biodegradation assay. Of the 3 isolated rhizobacteria, results revealed that Cronobacter sakazakii, diagnosed by gyrB gene, had the highest MP removal efficiency. These findings elucidated that both Alternanthera spp and a specific associated rhizobacterial strains have promising potentials in removing MP even though the latter possesses antimicrobial properties.