Bioaugmentation involving a bacterial consortium isolated from the rhizosphere of Spirodela polyrhiza for treating water contaminated with a mixture of four nitrophenol isomers

A flask-scale laboratory study was performed to assess the bioaugmentation of water contaminated with a mixture of 2-nitrophenol, 3-nitrophenol, 4-nitrophenol and 2,4-dinitrophenol by using a bacteria consortium consisting of three nitrophenol-degrading bacteria strains (Pseudomonas sp. strain MFR-1, Pseudomonas sp. strain PFR-1 and Rhodococcus sp. strain DFR-1), reinoculated into the roots of Spirodela polyrhiza. The selected strains were colonized into the root at approximately 10(4) to 10(6) colony-forming units (CFU per plant). The high populations remained stable through five sequential two-days degradation cycles and complete nitrophenol removal was achieved within five-repeated cycles. Hence, inoculation of subjected degraders into the roots of aquatic plants is an effective treatment for nitrophenol-contaminated effluents or aquatic resources.