Title
Measurement of Biologically Available Naphthalene in Gas and Aqueous Phases by Use of a Pseudomonas putida Biosensor
Author
TNO Voeding Centraal Instituut voor Voedingsonderzoek TNO
Werlen, C.
Jaspers, M.C.M.
van der Meer, J.R.
Publication year
2004
Abstract
Genetically constructed microbial biosensors for measuring organic pollutants are mostly applied in aqueous samples. Unfortunately, the detection limit of most biosensors is insufficient to detect pollutants at low but environmentally relevant concentrations. However, organic pollutants with low levels of water solubility often have significant gas-water partitioning coefficients, which in principle makes it possible to measure such compounds in the gas rather than the aqueous phase. Here we describe the first use of a microbial biosensor for measuring organic pollutants directly in the gas phase. For this purpose, we reconstructed a bioluminescent Pseudomonas putida naphthalene biosensor strain to carry the NAH7 plasmid and a chromosomally inserted gene fusion between the sal promoter and the luxAB genes. Specific calibration studies were performed with suspended and filter-immobilized biosensor cells, in aqueous solution and in the gas phase. Gas phase measurements with filter-immobilized biosensor cells in closed flasks, with a naphthalene-contaminated aqueous phase, showed that the biosensor cells can measure naphthalene effectively. The biosensor cells on the filter responded with increasing light output proportional to the naphthalene concentration added to the water phase, even though only a small proportion of the naphthalene was present in the gas phase. In fact, the biosensor cells could concentrate a larger proportion of naphthalene through the gas phase than in the aqueous suspension, probably due to faster transport of naphthalene to the cells in the gas phase. This led to a 10-fold lower detectable aqueous naphthalene concentration (50 nM instead of 0.5 uM). Thus, the use of bacterial biosensors for measuring organic pollutants in the gas phase is a valid method for increasing the sensitivity of these valuable biological devices.
Subject
Biotechnology
Bioluminescence
Biosensors
Calibration
Genes
Detection limits
Naphthalene
Naphthalene derivative
Aqueous solution
Bioluminescence
Biosensor
Calibration
Cell transport
Chromosome insertion
Concentration response
Gas analysis
Gene construct
Gene fusion
Immobilization
Luxab gene
Nonhuman
Organic pollution
Partition coefficient
Plasmid
Promoter region
Pseudomonas putida
Sal gene
Sensitivity analysis
Solubility
Suspension
Validation process
Bacterial Proteins
Biosensing Techniques
Chemiluminescent Measurements
Culture Media
Environmental Monitoring
Gases
Luciferases
Naphthalenes
Pseudomonas putida
Transcription Factors
Water
Bacteria (microorganisms)
insertion sequences
Negibacteria
Pseudomonas
Pseudomonas putida
To reference this document use:
http://resolver.tudelft.nl/uuid:f63e5ba6-e72e-4ccf-825f-1fd6d4ddeb48
DOI
https://doi.org/10.1128/aem.70.1.43-51.2004
TNO identifier
237579
ISSN
0099-2240
Source
Applied and Environmental Microbiology, 70 (70), 43-51
Document type
article