Team:Calgary/Project

From 2011.igem.org

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</html>[[Image:UofC2011_Whitbey.png|thumb|600px|center|<b>Figure 1.</b> Structure of Naphthenic Acids as discussed in Whitby, C. <i>et al.</i> 2010.]]<html>
</html>[[Image:UofC2011_Whitbey.png|thumb|600px|center|<b>Figure 1.</b> Structure of Naphthenic Acids as discussed in Whitby, C. <i>et al.</i> 2010.]]<html>
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<p>Naphthenic Acids (NAs) are a group of recalcitrant, hydrophobic, compounds which may contain a variety of structures.  All napthenic acids contain a conserved carboxylic acid group followed by a hydrocarbon chain.  Attached to this hydrphobic chain can be between one and four hydrogenated ring systems.  The classification of what defines a napthenic acid has been of great debate in the scientific community, but there diversity has made them difficult to better understand them. NAs are natively found in oil sands deposits and their surfactant quality contributes to a higher efficiency of oil sands recovery in the hot water extraction process. The majority of the NAs end up in large tailings ponds with the water used in the bitumen extraction process. The NAs continuously accumulate in these large tailings ponds along with other wastes generated in the bitumen extraction process which are left to settle to the bottom of the pond.</p>
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<p>Naphthenic Acids (NAs) are a group of recalcitrant, hydrophobic, compounds which may contain a variety of structures.  All naphthenic acids contain a conserved carboxylic acid group followed by a hydrocarbon chain.  Attached to this hydrophobic chain can be between one and four hydrogenated ring systems.  The classification of what defines a naphthenic acid has been of great debate in the scientific community, with their diversity has contributed to difficulties targeting them in biodegredation. NAs are natively found in oil sands deposits and their surfactant quality aids in a higher efficiency of oil sands recovery in the hot water extraction process. The majority of NAs end up in large tailings ponds with a variety of other toxic bioproducts of bitumen extraction. The NAs continuously accumulate in these large tailings ponds and are allowed to settle to the bottom of these pools.</p>
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</html>[[Image:UofC_TailingPond.png|thumb|600px|center|<b>Figure 1.</b> Courtesy of Pembina]]<html>
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</html>[[Image:UofC_TailingPond.png|thumb|600px|center|<b>Figure 2.</b> Courtesy of Pembina]]<html>
<h2>The Toxicity of Naphthenic Acids</h2>
<h2>The Toxicity of Naphthenic Acids</h2>
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<p>Unfortunately NAs are a contributor to corrosion in equipment and pipelines. In addition, their surfactant nature also makes them toxic as it allows them to pass through cell membranes and adversely affect a plethora of local organisms. The higher the concentration of the NAs in the environment the greater the potential harm to the local ecosystem.</p>  
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<p>One of the major industry concerns with NAs are their contribution to corrosion in equipment and pipelines. In addition, their surfactant nature also makes them toxic in mammalian systems allowing them to pass through and potentially disrupt cell membranes. NA's with a higher molecular weight are typically less toxic than those with a lower molecular weight.  These lower molecular weight compounds have been shown to have LC<sub>50</sub> values of less than 50 mg/L in freshwater systems. The higher the concentration of the NAs in the environment the greater the potential harm to the local ecosystem, in particular their contamination of biological communities surrounding the tailings ponds.</p>  
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</html>[[Image:UCalgary2011_LC50_values_for_fish_and_stuff.png|thumb|600px|center|<b>Figure 1.</b> LC50 values for Adult kutum, sturgeon, and roach when exposed to Napthenic Acids. Adapted from Dokholyan VK., Magomedov AK. (1983). ]]<html>
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</html>[[Image:UCalgary2011_LC50_values_for_fish_and_stuff.png|thumb|600px|center|<b>Figure 3.</b> LC50 values for Adult kutum, sturgeon, and roach when exposed to Napthenic Acids. Adapted from Dokholyan VK., Magomedov AK. (1983). ]]<html>
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<h2>Monitoring Naphthenic Acids</h2>
<h2>Monitoring Naphthenic Acids</h2>
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<p>Having the ability to monitor the levels of NAs is mandated by Canadian law and would be useful in assessing whether or not any future detoxification or remediation efforts are effective. Other applications including examining the surrounding areas for seepage of NAs into ground water, and examine . Currently, the only ways to test for the presence of NAs are mass spectrometry and gas chromatography. These methods are both costly and inconvenient since samples must be taken off site for processing and interpreting results would take time. The University of Calgary’s iGEM team is working on developing a novel electrochemical biosensor which would allow for convenient on site monitoring of NAs. Certain components of the system would be re-useable while the actual bacteria involved in the sensing would be disposed after use.</p>
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<p>Having the ability to monitor the levels of NAs is mandated by Canadian law and would be useful in assessing whether or not any future detoxification or remediation efforts are effective. Other applications including examining the surrounding areas for seepage of NAs into ground water, and determining the extent of damage caused by oil based chemical spills. Currently, the only ways to test for the presence of NAs are mass spectrometry and gas chromatography. These methods are costly, require the experience of a trained technician, must be shipped to a facility to be processed, and takes up to several hours per analysis. The University of Calgary’s iGEM team is working on developing a novel electrochemical biosensor which would allow for cheap, quick, and convenient on site monitoring of NAs. The bacteria used to sense the naphthenic acids would be contained inside a device, and respond specifically to these compounds.  Their response would signal a change in electrochemical potential in the solution which could be used as a read-out for our device in a quantitative manner.</p>
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</html>[[Image:TeamCalgary2011 The Vision Image 2.png|thumb|600px|center|<b>Figure 1.</b> LC50 values for Adult kutum, sturgeon, and roach when exposed to Napthenic Acids. Adapted from Dokholyan VK., Magomedov AK. (1983). ]]<html>
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</html>[[Image:TeamCalgary2011 The Vision Image 2.png|thumb|600px|center|<b>Figure 4.</b> The Vision of our project.  The University of Calgary team imagined a device which could allow for on-site testing of water samples for naphthenic acids.  Solutions would be placed into the device, where a bacteria would recognize the concentration of naphthenic acids in solution and generate a response. This can be detected by the device and a quantitative interpretation of the data would be viewable by the user.]]<html>
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Revision as of 07:32, 28 September 2011


A Biosensor for Naphthenic Acids

Naphthenic Acids in the Oil Sands

Figure 1. Structure of Naphthenic Acids as discussed in Whitby, C. et al. 2010.

Naphthenic Acids (NAs) are a group of recalcitrant, hydrophobic, compounds which may contain a variety of structures. All naphthenic acids contain a conserved carboxylic acid group followed by a hydrocarbon chain. Attached to this hydrophobic chain can be between one and four hydrogenated ring systems. The classification of what defines a naphthenic acid has been of great debate in the scientific community, with their diversity has contributed to difficulties targeting them in biodegredation. NAs are natively found in oil sands deposits and their surfactant quality aids in a higher efficiency of oil sands recovery in the hot water extraction process. The majority of NAs end up in large tailings ponds with a variety of other toxic bioproducts of bitumen extraction. The NAs continuously accumulate in these large tailings ponds and are allowed to settle to the bottom of these pools.

Figure 2. Courtesy of Pembina

The Toxicity of Naphthenic Acids

One of the major industry concerns with NAs are their contribution to corrosion in equipment and pipelines. In addition, their surfactant nature also makes them toxic in mammalian systems allowing them to pass through and potentially disrupt cell membranes. NA's with a higher molecular weight are typically less toxic than those with a lower molecular weight. These lower molecular weight compounds have been shown to have LC50 values of less than 50 mg/L in freshwater systems. The higher the concentration of the NAs in the environment the greater the potential harm to the local ecosystem, in particular their contamination of biological communities surrounding the tailings ponds.



Figure 3. LC50 values for Adult kutum, sturgeon, and roach when exposed to Napthenic Acids. Adapted from Dokholyan VK., Magomedov AK. (1983).


Monitoring Naphthenic Acids

Having the ability to monitor the levels of NAs is mandated by Canadian law and would be useful in assessing whether or not any future detoxification or remediation efforts are effective. Other applications including examining the surrounding areas for seepage of NAs into ground water, and determining the extent of damage caused by oil based chemical spills. Currently, the only ways to test for the presence of NAs are mass spectrometry and gas chromatography. These methods are costly, require the experience of a trained technician, must be shipped to a facility to be processed, and takes up to several hours per analysis. The University of Calgary’s iGEM team is working on developing a novel electrochemical biosensor which would allow for cheap, quick, and convenient on site monitoring of NAs. The bacteria used to sense the naphthenic acids would be contained inside a device, and respond specifically to these compounds. Their response would signal a change in electrochemical potential in the solution which could be used as a read-out for our device in a quantitative manner.

Figure 4. The Vision of our project. The University of Calgary team imagined a device which could allow for on-site testing of water samples for naphthenic acids. Solutions would be placed into the device, where a bacteria would recognize the concentration of naphthenic acids in solution and generate a response. This can be detected by the device and a quantitative interpretation of the data would be viewable by the user.


Engineering the Biosensor

Engineering the biosensor involved three main components: finding an appropriate sensory element, characterizing a novel reporter and selecting and designing tools for an appropriate chassis for our system. Information on the sensory element can be found on our Promoter Project page. More details on our reporter can be found on the Reporter Project page. More details on our chassis can be found on our Chassis Project page.