KINETICS AND RESPONSE OF A PSEUDOMONAS-FLUORESCENS HK44 BIOSENSOR

The reporter bacterium, Pseudomonas fluorescens HK44 (HK44), was chara cterized in an immobilized state to investigate utility for deployment as a remote sensor in the subsurface. A packed-bed reactor with algin ate-immobilized HK44 simulated hydrodynamic conditions such as might b e found in a subsurface environment. The reporter bacterium, HK44, har bors a reporter plasmid, pUTK21, which contains a transcriptional fusi on between the nahG gene in the lower pathway of the catabolic plasmic NAH7 and a luxCDABE gene cassette. The upper nah pathway and the lux pathway in pUTK21 are induced by salicylate. The lux enzymes catalyze the light reaction. HK44 demonstrated a quantitative relationship betw een salicylate concentration and degradation. Light intensity mimicked salicylate concentration, whereas degradation was first order in biom ass and first order in salicylate concentration, with a degradation co nstant of 2.23 x 10(-2) dm(3) g(-1) min(-1). (C) 1977 John Wiley & Son s, Inc.