Development and demonstration of an immobilised-polyphenol oxidase bioprobe for the detection of phenolic pollutants in water

The development of a portable, disposable bioprobe incorporating mushroom p olyphenol oxidase immobilised on a synthetic membrane for this purpose is d escribed for the detection and semi-quantification of phenolic pollutants i n water. The enzyme, immobilised on a nylon membrane together with 3-methyl -2-benzothiazolinone hydrazone, produced ranges of maroon colours in phenol ic solutions and orange colours in cresylic solutions. The colour intensiti es produced were found to increase proportionally with increasing substrate concentration after 5 min exposure to the substrates. The bioprobe had a b road substrate specificity and was sensitive to substrate concentrations do wn to 0.05 mg l(-1). The enzyme activity of the bioprobe was not affected i n a pH range from 4 to 10 and in a temperature range from 5 degrees C to 25 degrees C. The bioprobe activity was not affected by various concentration s of salt and metal ions and was able to detect and semi-quantify phenolic substrates in industrial effluent samples. The bioprobe could be stored for 1 month without loss of enzyme activity. These features indicate that the commercialisation of such a bioprobe is feasible. (C) 1999 Elsevier Science B.V. All rights reserved.