We are developing a biosensor for triclosan, an antimicrobial agent whose use has environmental and human health implications. Triclosan inhibits enoyl acp reductase (Fabi). By measuring the rate at which triclosan inhibits Fabi, we can make a standard curve of percent inhibition vs triclosan, and use this standard curve to determine how much triclosan is present in a wastewater sample. We are investigating the activity of the Fabi enzyme from 8 different organisms on a panel of non-native substrates to determine the combination of Fabi and substrate that will yield the best results at the lowest cost. We can then engineer the enzyme to have greater specificity on the non-native substrate through computational design and kunkel mutagenesis. By coupling our biosensor with civic engagement measures, our goal is to raise awareness and accountability around environmental concerns and to empower citizens to participate in decisions being made about chemical use.