Amperometric quantification of total coliforms and specific detection of Escherichia coli.
The quantitative determination of total and fecal coliforms, as indicators of fecal pollution, is essential for water quality control. We developed a sensitive, inexpensive amperometric enzyme biosensor based on the electrochemical detection of beta-galactosidase activity, using p-amino-phenyl-beta-D-galactopyranoside as substrate, for determining the density of coliforms, represented by Escherichia coli and Klebsiella pneumoniae. The specific detection of E. coli was achieved using an antibody-coated electrode that specifically binds the target bacteria. Amperometric detection enabled the determination of 1000 colony-forming units/mL within 60-75 min. Preincubation for 5-6 h further increased the sensitivity more than 100-fold. The present experimental setup allowed the simultaneous analysis of up to eight samples, using disposable screen-printed electrodes.
Mittelmann
Adrian Schwartz
AS
Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Ramat-Aviv, Israel.
Ron
Eliora Z
EZ
Rishpon
Judith
J
D000906:Antibodies / Q000737:chemistry; D015374:Biosensing Techniques; D004563:Electrochemistry; D004926:Escherichia coli / Q000737:chemistry* / Q000201:enzymology; D007711:Klebsiella pneumoniae / Q000737:chemistry; D014871:Water Microbiology; D014876:Water Pollution; D014881:Water Supply / Q000032:analysis; D001616:beta-Galactosidase / Q000032:analysis
D000906:Antibodies; D001616:beta-Galactosidase