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Construction and evaluation of a metal ion biosensor
Author(s) -
Tescione Lia,
Belfort Georges
Publication year - 1993
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260420805
Subject(s) - biosensor , metal ions in aqueous solution , metal , chemistry , environmental chemistry , nanotechnology , materials science , organic chemistry
Abstract Escherichia coli , genetically engineered with a mercury(II)‐sensitive promoter and the lux genes from Vibrio fischeri , were used as microbial bioluminescent sensors for the detection of mercury. Evaluation of this genetic construction was carried out by determining the effects of various parameters on cell suspensions maintained at constant conditions in a small 100‐mL vessel. The strongest light intensities and quickest induction times occurred with cells in the midexponential growth phase maintained at 28°C, concentrated to 1 × 10 9 cells/mL, mixed at very fast speeds, and aerated at 2 vvm (volume of air per volume of culture per minute) during light measurement in the small vessel. The cells were sensitive to the mercuric ion in the range of 20 n M to 4 μ M (4 to 800 ppb), and the total response time was on the order of 1 hour, depending on the above parameters. The cells exhibited great specificity for mercury. The cells had almost equal specificity for organic and inorganic forms of the mercuric ion and responded more weakly to the mercurous ion. A simple, inexpensive, durable miniature probe (3 mL) was constructed and operated using the optimum parameters found in the small vessel as a guide. The range of sensitivity to the mercuric ion detected in the probe was 10 n M to 4 μ M when aeration was provided. © 1993 John Wiley & Sons, Inc.