Background and Aims: Conventional cultural methods defined by the European Directives require 18-24 hours for the statutory assessment of the bacteriological water quality, and 1-2 days more, for results confirmation. Since delayed results can threaten public health, cutting-edge technologies able to speed up analyses are needed. Biosensors can represent devices which allow easy, rapid and on site analyses suitable for environmental applications. The advantage is their highly specific target's identification reducing the analytical steps. On this basis, a novel, completely automatic optical biosensor system (patent pending) able to rapidly detect Escherichia coli (E. coli) in marine water was developed. It can perform the entire analytical procedure and its autonomy is guaranteed by the provision of a stand-alone supply box, including substrate stock and a communication system that constantly interacts, by UMTS network, with a web server where results are shown for remote control. Methods: The principle of the analysis is based on the hydrolysis of the substrate beta-D-glucuronide contained in the culture medium added to the sample. The hydrolysis, operated by the microbial enzyme beta-D-glucuronidase, leads to 4-methylumbelliferone, whose fluorescence is measured, giving evidence of the presence of E. coli. In order to validate the system, results were compared with those gained with a standard method (ISO 9308-1:2012) able to quantify E. coli growth. Results: The developed biosensor system reliably detected E. coli as low as 1 cfu/mL in marine water in a maximum of 10-12 hours. This enabled a minimum of two analyses per day, therefore a tighter control of water conditions and near real-time results. Conclusions: This study paves the way for the development of an automatic monitoring platform, remotely controllable, intended for the management of water resources and acting as an early warning system launching alarm signals when fixed threshold values are exceeded.
Rapid detection of Escherichia coli in marine water samples by remote optical biosensor system
K Buonasera;G Pezzotti Escobar;
2017
Abstract
Background and Aims: Conventional cultural methods defined by the European Directives require 18-24 hours for the statutory assessment of the bacteriological water quality, and 1-2 days more, for results confirmation. Since delayed results can threaten public health, cutting-edge technologies able to speed up analyses are needed. Biosensors can represent devices which allow easy, rapid and on site analyses suitable for environmental applications. The advantage is their highly specific target's identification reducing the analytical steps. On this basis, a novel, completely automatic optical biosensor system (patent pending) able to rapidly detect Escherichia coli (E. coli) in marine water was developed. It can perform the entire analytical procedure and its autonomy is guaranteed by the provision of a stand-alone supply box, including substrate stock and a communication system that constantly interacts, by UMTS network, with a web server where results are shown for remote control. Methods: The principle of the analysis is based on the hydrolysis of the substrate beta-D-glucuronide contained in the culture medium added to the sample. The hydrolysis, operated by the microbial enzyme beta-D-glucuronidase, leads to 4-methylumbelliferone, whose fluorescence is measured, giving evidence of the presence of E. coli. In order to validate the system, results were compared with those gained with a standard method (ISO 9308-1:2012) able to quantify E. coli growth. Results: The developed biosensor system reliably detected E. coli as low as 1 cfu/mL in marine water in a maximum of 10-12 hours. This enabled a minimum of two analyses per day, therefore a tighter control of water conditions and near real-time results. Conclusions: This study paves the way for the development of an automatic monitoring platform, remotely controllable, intended for the management of water resources and acting as an early warning system launching alarm signals when fixed threshold values are exceeded.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
