Effect of Fe–Pd bimetallic nanoparticles on Sphingomonas sp. PH-07 and a nano-bio hybrid process for triclosan degradation

In this study, we have evaluated the effect of palladium–iron bimetallic nanoparticles (nFe–Pd) on diphenyl ether (DE) degrading bacterial strain Sphingomonas sp. PH-07 as well as a sequential nano-bio hybrid process with nFe–Pd as catalytic reductant and PH-07 as biocatalyst for degradation of triclosan. Strain PH-07 grew well in the presence of nFe–Pd up to 0.1 g/L in minimal salts medium with DE as carbon source. In aqueous system, TCS (17.3 μM) was completely dechlorinated within 2 h by nFe–Pd (0.1 g/L) with concomitant release of 2-phenoxyphenol (16.8 μM) and chloride ions (46 μM). All possible dichloro- and monochloro-2-phenoxyphenol intermediates were identified by HPLC and GC–MS analyses, and the dechlorination pathway was proposed. Addition of PH-07 cells into the reactor effectively degraded the 2-phenoxyphenol. Our results reveal that strain PH-07 survives well in the presence of nFe–Pd and nFe–Pd/PH-07 hybrid treatment could be a potential strategy for degradation of TCS.