title: High potential application in bioremediation of selenate by Proteus hauseri strain QW4.
abstract: OBJECTIVE
  Selenium is essential for biological systems at low concentrations and toxic at higher levels. Heavy metals and metalloids such as selenium are major contaminants in 40% of hazardous waste sites. Thus, bioremediation has been considered as an effective means of cleaning up of selenium-contaminated sites.
  
  
  METHODS
  In this study, 30 strains were isolated from wastewater samples collected from selenium-contaminated sites in Qom, Iran using the enrichment culture technique. One bacterial strain designated QW4, identified as Proteus hauseri by morphological, biochemical and 16S rRNA gene sequencing was studied for its ability to tolerate different concentrations of sodium selenate (100-800 mM). Also, the disk diffusion method was performed to determine resistance to some antibiotics.
  
  
  RESULTS
  Strain QW4 showed maximum minimum inhibitory concentration (MIC) to selenate (760 mM). The maximum selenate removal was exhibited at 35 °C, while the removal activity reduced by 30.7% and 37% at 25 °C and 40 °C, respectively. The optimum pH and shaking incubator for removal activity was shown to be 7.0 and 150 rpm, with 60.2% and 60.3%, respectively. This bacterial strain was resistant to some antibiotics.
  
  
  CONCLUSIONS
  The concentration of toxic sodium selenate (1000 μg/ml) in the supernatant of the bacterial culture medium decreased by 100% after 2 days and the color of the medium changed to red due to the formation of less toxic elemental selenium. Also, our results imply that heavy metal pollution may contribute to increased antibiotic resistance through indirect selection.
authors.affiliation: Department of Microbiology, Faculty of Basic Sciences, Qom Branch, Islamic Azad University, Qom, Iran.
authors.forename: Mohaddeseh
authors.initials: M
authors.lastname: Khalilian
authors.affiliation: Department of Microbiology, Faculty of Basic Sciences, Qom Branch, Islamic Azad University, Qom, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Zolfaghari
authors.affiliation: Department of Microbiology, Faculty of Basic Sciences, Qom Branch, Islamic Azad University, Qom, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Soleimani
keywords: Bioremediation; MIC; Proteus hauseri; Sodium selenate