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Developing a rapid flow cytometry method to determine ultraviolett light-emitting-diode (UV-LED) -mediated killing of bacteria in drinking water.

Jacobson, Stina LU (2016) KMBL01 20161
Applied Microbiology
Biotechnology
Department of Chemistry
Abstract
A next-generation drinking water purification device has been developed which uses UV-LEDs to create high intensity UV light to inactive the bacteria present in the water that flows through the device tube chamber. The capacity of the different setups of the devices to perform water purification was examined by experimental testing.
This report investigates using a new flow cytometry approach compared to the traditional Colilert method to develop a faster and higher throughput method for testing of the UV-LED water purification, and to do this, a routine for the experimental testing was developed.
The development of a well working and robust experimental routine resulted in a strain change. E. coli JM109 lab (Lab strain) was shown to be... (More)
A next-generation drinking water purification device has been developed which uses UV-LEDs to create high intensity UV light to inactive the bacteria present in the water that flows through the device tube chamber. The capacity of the different setups of the devices to perform water purification was examined by experimental testing.
This report investigates using a new flow cytometry approach compared to the traditional Colilert method to develop a faster and higher throughput method for testing of the UV-LED water purification, and to do this, a routine for the experimental testing was developed.
The development of a well working and robust experimental routine resulted in a strain change. E. coli JM109 lab (Lab strain) was shown to be affected by tap water, and replaced with E. coli DSMZ1116 (Wild strain) that proved to have a higher growth rate and shares more characteristics with bacteria that could be encountered in a real contamination event. After measuring the percentage of live cells in the bacterial inoculum samples it could also be concluded that the bacteria were not affected by being incubated overnight in a fridge. A routine for testing the purification devices was developed and the importance of a homogenous water-bacteria starting solution was noted. The mixing method that showed the best result was by using a whisk.
To investigate the ability of the UV-LED devices to kill E. coli, a standard growth curve was done for water-bacteria solutions with concentrations corresponding to log-reductions of a known concentration. For better reliability more growth curves should be performed, however, the standard growth curve for this project could be compared with the results from the flow cytometry and Colilert methods from the tests on the different device setups to help confirm their ability to kill bacteria.
Using the different experimental methods, it could be confirmed that the device setup that showed to have the best killing was the device with brushed aluminium reflectors and plane quartz glass tube. There was less killing of the bacteria when the water was flowing through the device at higher flow rates.
The results from the Colilert method performed by VA-Syd and the flow cytometry results, followed the same pattern showing the differences between the tests using different flow rates for each of the devices. However, in order to be able to confirm that flow cytometry is a reliable and applicable method to use for the experimental testing of UV-LED killing, more comparative tests of the different methods are needed. (Less)
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author
Jacobson, Stina LU
supervisor
organization
course
KMBL01 20161
year
type
M2 - Bachelor Degree
subject
keywords
teknisk mikrobiologi, applied microbiology
language
English
id
8890980
date added to LUP
2016-11-08 08:54:31
date last changed
2016-11-08 08:54:31
@misc{8890980,
  abstract     = {A next-generation drinking water purification device has been developed which uses UV-LEDs to create high intensity UV light to inactive the bacteria present in the water that flows through the device tube chamber. The capacity of the different setups of the devices to perform water purification was examined by experimental testing.
This report investigates using a new flow cytometry approach compared to the traditional Colilert method to develop a faster and higher throughput method for testing of the UV-LED water purification, and to do this, a routine for the experimental testing was developed. 
The development of a well working and robust experimental routine resulted in a strain change. E. coli JM109 lab (Lab strain) was shown to be affected by tap water, and replaced with E. coli DSMZ1116 (Wild strain) that proved to have a higher growth rate and shares more characteristics with bacteria that could be encountered in a real contamination event. After measuring the percentage of live cells in the bacterial inoculum samples it could also be concluded that the bacteria were not affected by being incubated overnight in a fridge. A routine for testing the purification devices was developed and the importance of a homogenous water-bacteria starting solution was noted. The mixing method that showed the best result was by using a whisk. 
To investigate the ability of the UV-LED devices to kill E. coli, a standard growth curve was done for water-bacteria solutions with concentrations corresponding to log-reductions of a known concentration. For better reliability more growth curves should be performed, however, the standard growth curve for this project could be compared with the results from the flow cytometry and Colilert methods from the tests on the different device setups to help confirm their ability to kill bacteria. 
Using the different experimental methods, it could be confirmed that the device setup that showed to have the best killing was the device with brushed aluminium reflectors and plane quartz glass tube. There was less killing of the bacteria when the water was flowing through the device at higher flow rates. 
The results from the Colilert method performed by VA-Syd and the flow cytometry results, followed the same pattern showing the differences between the tests using different flow rates for each of the devices. However, in order to be able to confirm that flow cytometry is a reliable and applicable method to use for the experimental testing of UV-LED killing, more comparative tests of the different methods are needed.},
  author       = {Jacobson, Stina},
  keyword      = {teknisk mikrobiologi,applied microbiology},
  language     = {eng},
  note         = {Student Paper},
  title        = {Developing a rapid flow cytometry method to determine ultraviolett light-emitting-diode (UV-LED) -mediated killing of bacteria in drinking water.},
  year         = {2016},
}