Benzonitrile is used as a solvent and chemical intermediate in the pharmaceutical, dyestuffs and rubber industries. It is highly toxic and harmful in contact with skin. The microbial degradation of benzonitrile proceeds through two enzymatic pathways. One is the nitrilase pathway, in which nitrilase directly converts benzonitrile to benzoate and ammonia ([http://www.ncbi.nlm.nih.gov/pubmed/2737207|Kobayashi et al., 1989]). In the other pathway, this conversion proceeds by a combination of nitrile hydratase and amidase ([http://www.ncbi.nlm.nih.gov/pubmed/7916690|Kobayashi et al., 1993]).