First tests with a prototype flow-through real-time bacterial toxicity sensor for water contaminants

In the Netherlands, the chemical quality of drinking water is currently guarded by biomonitors at inlets
of raw surface water, and chemical analysis of raw and drinking water. Although this is quite an
advanced system already, it is still not optimal in view of protecting the health of consumers. What lacks
is a sensory system that can rapidly (in real-time) detect the presence of all important human toxicants in
water used for the preparation of drinking water.
In the past decade or so, bacterial strains have been developed that can detect the total effect of
contaminants causing human toxicity, e.g. genotoxicity, membrane damage, oxidative damage and
protein damage, providing results within 1-2 h. These bacteria are genetically modified organisms
(GMOs), engineered to luminesce after exposure to certain toxic compounds. The suitability of
employing these bacteria for testing static water samples on the presence of contaminants has been
demonstrated previously.
In this study, a flow-through fiber-optic-based bacterial monitoring system for online monitoring of toxic
pollutants in water has been developed. Two bacterial strains containing fusions of recA (DNA damage)
and grpE (heat-shock) promoters to the lux operon (CDABE) were immobilized on a fiber optic and
tested for their ability to detect pollutants in flowing tap water and surface water in this new system.