Specific detection of p-chlorobenzoic acid by Escherichia coli bearing a plasmid-borne fcbA':: lux fusion

In this communication we report on a genetically engineered bacterium that reacts by light emission to the presence of 4-chlorobenzoic acid. To constr uct this strain, DNA fragment (1.7 kb) upstream from the 4-chlorobenzoic ac id dehalogenase (fcb) operon of Arthrobacter SU was fused to Vibrio fischer i luxCDABE genes. An Escherichia coli strain transformed with a multi-copy plasmid (pASU) bearing this fusion responded to the presence of 4-chloroben zoic acid and a few closely related compounds by increased luminescence, ex hibiting a high specificity but a relatively low sensitivity. While it coul d be somewhat, improved by manipulating the experimental pH, sensitivity re mained too low for real time applicability. Nevertheless, the principle of using dehalogenase promoters as environmental pollution sensor was demonstr ated. (C) 1998 Elsevier Science Ltd. All rights reserved.