Creating a multifunctional degrader for co-mineralization of p-nitrophenol and 1,2-dichloroethane and its application in wastewater bioremediation.

Because the interactions among contaminants may lead to enhanced toxicity, combined pollution caused by the co-presence of multiple contaminants has increasingly gained public concern. p-Nitrophenol (PNP) and 1,2-dichloroethane (1,2-DCA) are frequently co-detected in groundwater. To completely eliminate PNP, 1,2-DCA and intermediates from polluted sites, in this study, a novel degrader KTU-PDG was created by functional assembly of PNP and 1,2-DCA biodegradation pathways in a robust chassis Pseudomonas putida KT2440. Cell growth assay indicated that PNP or 1,2-DCA can be metabolized as a sole carbon source by strain KTU-PDG for cell proliferation. Stable isotope analysis indicated that strain KTU-PDG possesses the capability of co-mineralizing PNP and 1,2-DCA to CO in mineral salt medium. In wastewater bioremediation, the strain KTU-PDG was proven to be capable of co-mineralizing PNP and DCA and maintained high cell viability during bioremediation. Herein, we demonstrate for the first time co-mineralization of PNP and 1,2-DCA by a single strain. Moreover, green fluorescent protein (GFP)-labeling of strain KTU-PDG facilitates estimation of viable cell number and real-time monitoring of cellular activity and transfer by autofluorescence in the environment. These merits of strain KTU-PDG highlight great potential of this degrader for in situ bioremediation of sites co-contaminated with PNP and 1,2-DCA. More importantly, this strategy of multi-pathways assembly in an optimal chassis shows good potential for the clean-up of combined pollution caused by other organic pollutants.