Development of Microbial Biosensors for BOD and other Water-Quality Related Parameters

SANTIAGO CHIAPPINI; DIEGO KORMES; ALBERTO A. VIALE; EDUARDO CORTÓN

Pinamar, Argentina

Congreso; X Congress of the Panamerican Association for Biochemistry and Molecular Biology (PABMB), the XLI Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology (SAIB) and the XX Annual Meeting of the Argentine Society for Neurochemistry; 2005

Sociedad Argentina de Investigaciones Bioquímicas y otras

Environmental biosensors are a growing area of application, despite the still small participation on the worldwide biosensor market, where clinical glucose sensors explain close to 90% of the total sales. We developed microbial based biosensors, by coupling or immobilized a single microbial strain or a mixed community in close contact with two different transducers, a potentiometric carbon dioxide electrode or a thermistor. These two ways to following metabolic activity of the immobilized cells allow us the estimation of BOD5 in less than a half an hour; BOD calibration was made using two commonly used standards, a glucose-glutamic acid solution (GGA) and OECD solution. The biosensor was used in batch experiments or as detector in a FIA system, where the electrode was inserted in a house-made cell, in a typical set-up, by using a peristaltic pump and a low pressure 6 ways injector valve. The use of lyophilized microbial material allows us high standardization of the microbial compositions and physiological behavior between different biosensor membranes; the correlation between our data (BODst, short term BOD) and the standard BOD (BOD5) was good when standard solutions are compared, but when real samples are measured the biosensor behavior was strongly dependent of waste-water composition.