Development and Validation of an On-Line Water Toxicity Sensor with Immobilized Luminescent Bacteria for On-Line Surface Water Monitoring

Abstract

Surface water used for drinking water production is frequently monitored in The Netherlands using whole organism biomonitors, with for example Daphnia magna or Dreissena mussels, which respond to changes in the water quality. However, not all human-relevant toxic compounds can be detected by these biomonitors. Therefore, a new on-line biosensor has been developed, containing immobilized genetically modified bacteria, which respond to genotoxicity in the water by emitting luminescence. The performance of this sensor was tested under laboratory conditions, as well as under field conditions at a monitoring station along the river Meuse in The Netherlands. The sensor was robust and easy to clean, with inert materials, temperature control and nutrient feed for the reporter organisms. The bacteria were immobilized in sol-gel on either an optical fiber or a glass slide and then continuously exposed to water. Since the glass slide was more sensitive and robust, only this setup was used in the field. The sensor responded to spikes of genotoxic compounds in the water with a minimal detectable concentration of 0.01 mg/L mitomycin C in the laboratory and 0.1 mg/L mitomycin C in the field. With further optimization, which should include a reduction in daily maintenance, the sensor has the potential to become a useful addition to the currently available biomonitors.

Live-Cell Systems in Real-Time Biomonitoring of Water Pollution: Practical Considerations and Future Perspectives

“…There have been, however, several noteworthy and very promising attempts to develop online and flow through biomonitoring technologies using microbial cell immobilisation techniques. In those systems, the immobilisation of bacteria has been predominantly achieved using sol-gel chemistries that embed cells directly on fibre optic elements or form biofilms on different matrixes [94][95][96]. The replacement of sensing elements can be reduced by the utilisation of genetically engineered strains with bioluminescent or fluorescent switch on-switch off genetic constructs.…”

“…Perhaps one of the best practical validation examples includes a recent prototype of a bacterial online monitor that employed an engineered bioluminescent strain of Escherichia coli. It was field tested for potential practical deployment in a water monitoring station Keizersveer (Hank, The Netherlands) located on the river Meuse (Figure 4) [94]. Its performance was also directly compared with the existing installations of animal behaviour-based BEWSs such as DaphTox II (bbe-Moldaenke GmbH, Germany) and the Musselmonitor ®® (AquaDect, The Netherlands) that utilise freshwater crustacean Daphnia magna and bivalve mussel Dreissena rostriformis, respectively [94].…”

“…It was field tested for potential practical deployment in a water monitoring station Keizersveer (Hank, The Netherlands) located on the river Meuse (Figure 4) [94]. Its performance was also directly compared with the existing installations of animal behaviour-based BEWSs such as DaphTox II (bbe-Moldaenke GmbH, Germany) and the Musselmonitor ®® (AquaDect, The Netherlands) that utilise freshwater crustacean Daphnia magna and bivalve mussel Dreissena rostriformis, respectively [94]. Interestingly, the field trials demonstrated the much lower overall sensitivity of the bacterial online monitoring [94].…”

“…Its performance was also directly compared with the existing installations of animal behaviour-based BEWSs such as DaphTox II (bbe-Moldaenke GmbH, Germany) and the Musselmonitor ®® (AquaDect, The Netherlands) that utilise freshwater crustacean Daphnia magna and bivalve mussel Dreissena rostriformis, respectively [94]. Interestingly, the field trials demonstrated the much lower overall sensitivity of the bacterial online monitoring [94]. This was expected since the system employed only one genetically engineered DPD2794 strain of E. coli that sensed the occurrence of DNA damage (recA promoter cloned with the luxCDABE genes of Aliivibrio fischeri) [91].…”

Rapid detection and toxicity assessment of ochratoxin A by Photobacterium leiognathi in drinking water

“…Those techniques have limitations like time-consuming, costly, lack of toxicological evaluation and requirement for a skilled technician. On the other hand, luminescent bacteria assay (LBA) exhibits its advantages of low cost, easy to perform and subculture for reuse, and can be served as good indicators for rapid ecotoxicology assessment by IC 50 values; which has been extensively applied in monitoring environmental pollution, herbicide residuals and toxicity analysis (Woutersen et al, 2017). The LBA is based on the biological response of luminescent bacteria, which are self-maintained luminescent that emit a strong and stable blue-green wavelength light (450-490 nm) and the optical signals can be determined precisely by photomultipliers (PMT; Komaitis et al, 2010).…”