Detection of Cr6+ by the sulfur oxidizing bacteria biosensor: Effect of different physical factors

Sedky H.A. Hassan, Steven W. Van Ginkel, Sang Eun Oh*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


A biosensor based on sulfur-oxidizing bacteria (SOB) for detection of toxic chemicals in water was developed. SOB are acidophilic microorganisms that get their energy through the oxidation of reduced sulfur compounds in the presence of oxygen to produce sulfuric acid. The reaction results in an increase in electrical conductivity (EC) and a decrease in pH. The bioassay is based on the inhibition of SOB in the presence of toxic chemicals by measuring changes in EC and pH. The effect of different physical factors such as HRT, inorganic sulfur (S°) particle size, and temperature on detection of Cr6+ was studied. The detection of Cr6+ (50 ppb) was improved by decreasing the hydraulic retention time (HRT) from 30 to 10 min and increasing S° particle size from 1 to 4.75 mm. Detection time was shorter at 30 °C compared to 45 °C and the SOB were active over a wide range of temperatures with a maximum temperature for growth at 45 °C. This novel biosensor is simple, highly sensitive to low Cr6+ concentrations (50 ppb), and also minimizes detection time. The present findings can be applied to the proper continuous screening of water ecosystem toxicity.

Original languageEnglish
Pages (from-to)7844-7848
Number of pages5
JournalEnvironmental Science and Technology
Issue number14
Publication statusPublished - Jul 17 2012
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry


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