title: Volatilization of arsenic from polluted soil by Pseudomonas putida engineered for expression of the arsM Arsenic(III) S-adenosine methyltransferase gene.
abstract: Even though arsenic is one of the most widespread environmental carcinogens, methods of remediation are still limited. In this report we demonstrate that a strain of Pseudomonas putida KT2440 endowed with chromosomal expression of the arsM gene encoding the As(III) S-adenosylmethionine (SAM) methyltransfase from Rhodopseudomonas palustris to remove arsenic from contaminated soil. We genetically engineered the P. putida KT2440 with stable expression of an arsM-gfp fusion gene (GE P. putida), which was inserted into the bacterial chromosome. GE P. putida showed high arsenic methylation and volatilization activity. When exposed to 25 μM arsenite or arsenate overnight, most inorganic arsenic was methylated to the less toxic methylated arsenicals methylarsenate (MAs(V)), dimethylarsenate (DMAs(V)) and trimethylarsine oxide (TMAs(V)O). Of total added arsenic, the species were about 62 ± 2.2% DMAs(V), 25 ± 1.4% MAs(V) and 10 ± 1.2% TMAs(V)O. Volatilized arsenicals were trapped, and the predominant species were dimethylarsine (Me2AsH) (21 ± 1.0%) and trimethylarsine (TMAs(III)) (10 ± 1.2%). At later times, more DMAs(V) and volatile species were produced. Volatilization of Me2AsH and TMAs(III) from contaminated soil is thus possible with this genetically engineered bacterium and could be instrumental as an agent for reducing the inorganic arsenic content of soil and agricultural products.
authors.affiliation: Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University , Miami, Florida 33199, United States.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.forename: Guo-Xin
authors.initials: GX
authors.lastname: Sun
authors.forename: Xiao-Xue
authors.initials: XX
authors.lastname: Wang
authors.forename: Víctor de
authors.initials: Vd
authors.lastname: Lorenzo
authors.forename: Barry P
authors.initials: BP
authors.lastname: Rosen
authors.forename: Yong-Guan
authors.initials: YG
authors.lastname: Zhu
mesh_terms: D001151:Arsenic / Q000378:metabolism* / Q000633:toxicity; D001152:Arsenicals / Q000378:metabolism; D001673:Biodegradation, Environmental / Q000187:drug effects; D002876:Chromosomes, Bacterial / Q000235:genetics; D004787:Environmental Pollution / Q000032:analysis*; D005453:Fluorescence; D005798:Genes, Bacterial; D005818:Genetic Engineering; D008745:Methylation / Q000187:drug effects; D008780:Methyltransferases / Q000235:genetics*; D016958:Pseudomonas putida / Q000187:drug effects / Q000235:genetics*; D012241:Rhodopseudomonas / Q000201:enzymology; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000378:metabolism*; D014835:Volatilization / Q000187:drug effects
chemical_list: D001152:Arsenicals; D012987:Soil; D012989:Soil Pollutants; D008780:Methyltransferases; D001151:Arsenic