Experimental development of a biosensor system to measure the concentration of phenol diluted in water using alternative sources of oxidoreductase enzymes.

The presence of phenol in industrial wastewater is an issue of great relevance for petrochemical and energy companies, among others. The high toxicity level of this substance requires polluting industries to continuously monitor the concentration of phenol in their wastewaters so as to comply with environmental regulations and to minimize environmental impact. This research work proposes the experimental development of an analytical method for "in situ" measurement of the concentration of phenol diluted in water, with application in Oil & Gas production wastewater monitoring. The method is based on the principle of selectivity exhibited by the oxidoreductase enzymes in the presence of phenolic compounds. The differences in the performance found when using organic tissues and microorganisms, as natural alternative sources of the enzyme, are also highlighted. These alternative sources of oxidoreductase enzyme work as the recognition element of the biosensor. A dissolved oxygen sensor is used as the transducer of the chemical signal produced by the reaction between the analyte and the enzyme. The bioencapsulation technique is very adequate in this case, because it offers a nutrient medium to the microorganisms and is reusable, making it ideal for repetitive measurement applications. The results show that the biosensor exhibits an approximately linear behavior when measuring phenol concentrations from 0.2 to 2 ppm.