The human pathogens in contaminated water are too varied to reasonably test for their presence. The presence of the normal human enteric bacteria E.coli has been used as a marker for contamination but their are concerns that it might not persist in the environment as long as the human pathogenic virus will. Another dependable marker of water contaminated by human waste is the presence of bacteriophage of the human intestines or so-called "coliphage." These have been found to be more stable under various environmental conditions. Our biosensor is designed to report the lysis of target cells from coliphage by the release of one of two fragments of the enzyme beta-galactosidase (Omega fragment). Upon release, the beta-galactosidase omega fragment joins beta-galactosidase alpha fragments that are suspended by the added contaminated water. After the two fragments join, beta-galactosidase enzyme activity is formed and an enzyme substrate present is converted to its colorimetric form. The amount of color development will be quantified by comparison with a parallel test with known amount of coliphage present.
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