The CU Boulder iGEM team was inspired by combining ideas from previous work and legislation related to fracking with recently-produced genetics including the use of logic gates and cell-to-cell signaling. This combination ultimately results in the most cutting-edge naphthalene biosensor for practical industrial use in controlling groundwater contamination due to fracking.
Despite fracking being a relatively recent topic among environmental discussions, the technology to drill vertical hydraulic fracturing wells has been around and used since 1940s. It wasn’t until the 1980s when George P. Mitchell, a petroleum engineer from Texas, invented the horizontal drilling process. Soon, no natural gas companies could survive unless the adapted the technique themselves. By the 1990s, more than 80% of natural gas in the United States was extracted with fracking, and environmentalists began to fear some of the unintended consequences of the practice. Chemistry and law quickly stepped in to evaluate remediation options, all of which has led to the creation of CU Boulder iGEM team’s device.
The first description of a whole-cell biosensor with environmental applications was described by researchers at the Swiss Federal Institute for Environmental Science and Technology. They engineered Pseudomonas putida bacteria to luminesce proportionately to aqueous naphthalene concentrations. However, these bacteria had complex biochemical pathways that were not well enough understood to be easily adjusted and refined. Furthermore, the cells were not sensitive enough to report the dilute naphthalene concentrations that fracking companies may be interested in reporting.
The Energy Policy Act of 2005 was passed to change US energy regulations, and restructuring tax incentives within the energy industries. Part of this bill included a provision that would exempt natural gas companies that use fracking from disclosing the chemicals involved that would normally be required of energy companies. While many drilling companies would benefit, it caused the started to grow skeptical about their intentions and the environmental impact of hydraulic fracturing.
According to their website, FracFocus Chemical Disclosure is a government run agency that was the first to provide public access to information on fracking and the chemicals used near homes. Naphthalene was reported as the most common, as it was found in more than 30% of all contamination sites. Recent legislation has required companies to register the chemicals they use on FracFocus, and it coordinates with reporting companies to keep updated records of contaminant history across the United States. The foundation of the site and coordinating legislation provided transparency, but few companies have been held accountable for data published through FracFocus.
Since the government had loose regulations on fracking contamination and people grew more concerned about the now-reported chemicals being used, the private sector’s demand for chemical sensors increased. OptiEnz is a leading biosensor development company that was founded by a professor at Colorado State University. Their product uses extracted enzymes and fiber optics to sense real-time pollution directly in the water source, preventing the need for pretreatment and skilled labor that has been previously required.
Based on information from their wiki, the 2013 iGEM team from Peking developed many parts to detect aromatic compounds. Among those produced were the NahR transcriptional regulator combined with a salicylate promoter and an sfGFP gene that can respond to naphthalene at concentrations within an order of magnitude of the EPA’s maximum of 20 µg/L. This part was thoroughly characterized and available in the distribution kit, so it quickly became the goal of the CU 2015 team to improve its use to make the system more sensitive, easier to use, and ultimately more practical for industrial application.
According to CNN, Houstonian Lisa Parr sued Aruba Petroleum for health problems that arose upon the construction of 22 natural gas wells within 2 miles of her home. She suspected that her families’ persistent nausea, migraines, and dizziness came as a result of toxic air and water pollution. Although the Aruba insisted that toxicologists and medical professionals supported that their operations posed no harm, the jury voted and awarded Parr a $2.9 million settlement. This case a need for the general public to have access to practical methods to measure of contamination, and that there may be demand for sensors outside of just private companies or regulatory agencies.
Michael van den Bossche from the University of Virginia proposed a network of sensors to track methane pollution in the air as a result of increased fracking use in the natural gas industry. This was among the first designs of a full-scale network of sensors that could run continuously as a large-scale operation. Because it can run continuously and is not dependent on instantaneous measurement from a sample or a single source, it can produce significant information with very low system maintenance following installation.
The Naphthalene Recorder project by CU Boulder iGEM incorporates the whole-cell concept for simplicity of processing and production and extends OptiEnz concept of measuring untreated samples from bodies of water by introducing a stake that can maintain homeostatic conditions wherever it’s placed. The concept of a low-maintenance network with contaminant “memory” extends the concept proposed for methane sensors, and its use can allow the public to run their own tests, avoiding lawsuits and not being strictly dependent upon the law requiring a company to run a test themselves.