title: Bacillus flexus strain As-12, a new arsenic transformer bacterium isolated from contaminated water resources.
abstract: A total of 14 arsenic-resistant bacteria were isolated from an arsenic-contaminated travertine spring water in the central district of Qorveh county, Kurdistan Province, Iran. One of strains designated As-12 was selected for further investigation because of its ability to transform arsenic. The strain was identified by cultural, morphological and biochemical tests, and 16S rRNA gene sequencing. Finally, the growth characteristics of the isolate were investigated in a chemically defined medium which included varied ranges of environmental factors such as pH, temperature and salinity. Moreover, the resistance of this strain to some heavy metals was evaluated. The bacterium was a Gram-positive, endospore-forming with all other characteristics of the genus Bacillus. It revealed maximum similarity at the 16S rRNA gene level with Bacillus flexus. The optimum growth of the strain was observed at 38 °C, pH 9 and 2% salinity. This strain was resistant to heavy metals such as zinc, chromium, lead, nickel, copper, mercuric and cadmium at concentrations of 15 mM, 15.5 mM, 11.5 mM, 12 mM, 11 mM, 5.5 mM, and 1 mM, respectively. The isolated bacterium was able to reduce As (V) to As (III) (about 28%) and oxidize As (III) to As (V) (about 45%) after 48 h of incubation at 37 °C. In conclusion, Bacillus flexus strain As-12, was identified as an arsenic transformer, for the first time.
authors.affiliation: Environmental Health Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: Mohammad Ahmadi
authors.initials: MA
authors.lastname: Jebeli
authors.affiliation: Environmental Health Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran. Electronic address: maleki43@yahoo.com.
authors.forename: Afshin
authors.initials: A
authors.lastname: Maleki
authors.affiliation: Extremophiles Laboratory, Department of Microbiology, Faculty of Biology University of Tehran, Tehran, Iran; Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Amoozegar
authors.affiliation: Dietary Supplement and Probiotic Research Center, Alborz University of Medical Sciences, Karaj, Iran. Electronic address: ekalantar@hotmail.com.
authors.forename: Enayatollah
authors.initials: E
authors.lastname: Kalantar
authors.affiliation: Research Center for Environmental Pollutants, School of Public Health, Qom University of Medical Sciences, Qom, Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Izanloo
authors.affiliation: Environmental Health Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: Fardin
authors.initials: F
authors.lastname: Gharibi
mesh_terms: D001151:Arsenic / Q000032:analysis*; D001407:Bacillus / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D001482:Base Composition; D001673:Biodegradation, Environmental; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D005227:Fatty Acids; D007492:Iran; D019216:Metals, Heavy / Q000633:toxicity; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D045483:Rivers / Q000737:chemistry* / Q000382:microbiology; D054712:Salinity; D017422:Sequence Analysis, DNA; D014874:Water Pollutants, Chemical / Q000032:analysis*; D062066:Water Resources
chemical_list: D004269:DNA, Bacterial; D005227:Fatty Acids; D019216:Metals, Heavy; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical; D001151:Arsenic
keywords: Arsenic; Bacillus flexus; Bioremediation; Water resource