Biosensor for the estimation of low biochemical oxygen demand

A highly sensitive sensor for biochemical oxygen demand (BOD) has been developed. Using Pseudomonas putida instead of glucose and glutamic acid artificial wastewater (AWW) was employed for calibration of the BOD sensor. Typical response times of the BOD sensor were 2-15 min, and the service life of the immobilized microorganisms is >10 days. The optimal BOD response was observed at 30 degrees C and pH 7.0. The lower limit of detection was 0.5 mg l(-1) BOD. The sensor response was not influenced by chloride ion up to 1000 mg l(-1), and also was not affected by heavy metal ions. For natural river waters, BOD values estimated by this biosensor correlate well with those determined by the conventional 5-day BOD test. (C) 1999 Elsevier Science B.V. All rights reserved.