Detection of Cr<SUP>6+</SUP> by the Sulfur Oxidizing Bacteria Biosensor: Effect of Different Physical Factors

초록

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 degrees) 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 mm and increasing S degrees particle size from 1 to 4.75 mm. Detection time was shorter at 30 degrees C compared to 45 degrees C and the SOB were active over a wide range of temperatures with a maximum temperature for growth at 45 degrees 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.

키워드