Initially described in 1990, Pseudomonas fluorescens HK44 served as the first whole-cell bioreporter genetically endowed with a bioluminescent (luxCDABE) phenotype directly linked to a catabolic (naphthalene degradative) pathway. HK44 was the first genetically engineered microorganism to be released in the field to monitor bioremediation potential. Subsequent to that release, strain HK44 had been introduced into other solids (soils, sands), liquid (water, wastewater), and volatile environments. In these matrices, it has functioned as one of the best characterized chemically-responsive environmental bioreporters and as a model organism for understanding bacterial colonization and transport, cell immobilization strategies, and the kinetics of cellular bioluminescent emission. This review summarizes the characteristics of P. fluorescens HK44 and the extensive range of its applications with special focus on the monitoring of bioremediation processes and biosensing of environmental pollution.

• Keywords
• Pseudomonas fluorescens HK44, bioluminescence, bioreporter, biosensors, lux genes,
• MeSH
• Equipment Failure Analysis MeSH
• Biosensing Techniques instrumentation   MeSH
• Biological Assay instrumentation   MeSH
• Equipment Design MeSH
• Spectrometry, Fluorescence instrumentation   MeSH
• Environmental Monitoring instrumentation   MeSH
• Pseudomonas fluorescens drug effects   physiology   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

The bioluminescence (BLM) and colony-forming units (CFU) of Pseudomonas fluorescens HK44 were monitored during encapsulation into pre-polymerized Si(OMe)₄. The non-induced BLM of free cells was increased in the presence of 0.5-2.5 % MeOH. After mixing silica sol with the cell suspension, both BLM and CFU dropped to 1-3 and 8-18 %, respectively; both remained lowered as long as the silica biofilm contained residual MeOH. The kinetics of MeOH being released from silica biofilms (a thickness of 2-6 mm) were first-order. The decrease of bacterial activity due to encapsulation was proportional to the biofilm thickness. MeOH evolving during encapsulation is probably the principal stress factor but not the only one.

• MeSH
• Luminescence * MeSH
• Methanol toxicity   MeSH
• Microbial Viability * MeSH
• Pseudomonas fluorescens physiology   MeSH
• Silica Gel toxicity   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Methanol MeSH
• Silica Gel MeSH