Cypermethrin is a synthetic insecticide of the pyrethroid family, which derive from botanical pyrethrins. Cypermethrin is classified as a Type II pyrethroid due to its alpha-cyano group. In the United States, about 1 million pounds of cypermethrin are applied annually, mostly to cotton crops (US EPA, 2008). Cypermethrin has relatively low toxicity for mammals and birds, although it is highly toxic for fish and aquatic invertebrates ([http://www.ncbi.nlm.nih.gov/pubmed/2646661|Bradbury and Coats, 1989]). The major route of cypermethrin biodegradation begins with ester hydrolysis (Roberts TR and Standen ME, Pest Management Science, 8:305-319, 1977), a common initial step in pyrethroid metabolism, to produce the carboxylate, 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate. The other product, cyano-3-phenoxybenzyl alcohol, contains the cyanohydrin functional group, which is unstable in the presence of water. The cyanohydrin eliminates HCN in a non-enzymatic reaction to produce 3-phenoxybenzaldehyde ([http://www.ncbi.nlm.nih.gov/pubmed/429687|Shono et al., 1979]).