A new microbial biosensor for organic water pollution based on measurement of carbon dioxide production

CHIAPPINI, SA; KORMES, DJ; BONETTO, MC; SACCO, N; CORTÓN, E

SENSORS AND ACTUATORS B-CHEMICAL

ELSEVIER SCIENCE SA

Año: 2010 vol. 148 p. 103 - 109

0925-4005

As aerobic respiration proceeds it consumes oxygen and produces carbon dioxide; and the relationbetween these two parameters, the respiratory quotient (RQ), is related to the type of substances beingrespired. Therefore, for a given water or wastewater origin, a more or less stable RQ is expected, makingpossible the estimation of BOD5 by means of CO2 production measurement. The microbial breathingintensity was continuously measured using a potentiometric CO2 electrode as transducer.Wenamed thisnew biosensor BODstCO2. Proof of concept in this study was carried out with Saccharomyces cerevisiae or aBODSEED mixed microbial community as a biological recognition component. The effect of microbial load(0.5, 5, and 25mgcm−2 membrane, dry weight) over the apparent linear range (up to 670mgL−1 BOD5,5mgcm−2 membrane), detection limit (ca. 1mg L−1 BOD5), stabilization time, reproducibility (typicallybetter than 10%) and bio-membrane type (membrane or PVA hydrogel entrapment) were studied. Whenthe Nernstian biosensor response was used for calibration, up to 20,000mgL−1 glucose standard wasmeasured without sample dilution. BOD calibrations were accomplished using the two more commonlyused standard artificial wastewaters, GGA and OECD solutions. The results showed that the potentiometricCO2 electrode was an useful transducer, allowing us to build, calibrate and characterize a BOD-likebiosensor. Moreover, limitations present at oxygen amperometric electrode (customarily used as BODbiosensor-based transducer) such as oxygen low solubility and its reduction at the cathode were avoided