Answering the Question: How Can Synthetic Biology Improve Fracking Sustainability

Fracking is an emerging technology to extract natural gas with huge benefits for companies but comes with severe environmental sustainability problems and toxic problems. Specifically, in the process of flowback, large amounts of methane gas leaks into the ground water and air, increasing the impact of global warming and causes methane gas to escape into people’s home. Our group knew that bacteria had been proposed for bio-remediation type projects before and we were eager to apply them to this fracking methane problem. Initially, our research led us in two directions: targeting the well water/home treatment phase or targeting the industrial emissions/REC (Reduced Emissions Completion: An environmentally friendly method of completing a gas-well) stage. We took our initial ideas to our interdisciplinary team of advisory experts, Dr. Mark Styczynski, a chemical engineer, Dr. Eric Gaucher, a biologist, and Dr. Wendy Newsletter, an ethnographer of engineering. They asked us to consider how a potential bio-remediation strategy would be practically implemented – which actors would have the technical savvy and economic resources to start up and control a bioremediation process? Through our conversations with them we chose to focus on the REC stage because industrial actors had the right mix of incentives and technical prowess to implement our project. In focusing our literature search on the REC process, we came up with adjustments to our initial idea by focusing on the gaseous chamber of the REC. If we could convert methane gas to a liquid (methanol), our literature search indicated we could eliminate the need for the REC to handle gaseous methane at all, considerably simplifying the workflow thereby making it easier to recover revenue, and reducing the impact of fracking on the environment.

We reviewed methane metabolism literature and discovered research into methanotrophs. Methanotrophs are bacteria that use methane gas as a source of energy and they have enzyme that can break down methane into methanol, called soluble methane monoxygenase or sMMO. Our goal (described below in detail) will be to insert the sMMO genes into E. coli to produce the sMMO protein with optimal rates of transcription and translation of the genes. This will allows us to answer the question: how can synthetic biology be used to solve the problem of environmental sustainability in fracking?

Fracking Sustainability: Past and Future

In the past, flowback extracted from wells after hydraulic fracturing has typically been stored in either open air pits or temporary storage tanks to await treatment, where it vents a large quantity of natural gas and other VOC's into the atmosphere. This venting often results in the loss of around 10,800 Mcf of natural gas (~$76,000 at $7 per Mcf) into the atmosphere^[1]. Previous attempts to capture this methane have been largely fruitless, as the sand present in the flow back would chew through the steel pipes or clog the machine altogether (see diagram), and the high volume of flowback would not allow time enough for particulates to settle out of the flowback.

However, work-overs and completions of new natural gas wells have recently begun employing the REC (reduced emission completion) technique. This technique employs a series of sand traps, separators, dehydrators, and condensers in order to extract methane and other gaseous and liquid hydrocarbons from the flowback mixture. The sand trap unsurprisingly removes sand and other particulates from the flow back, and uses water reclaimed from the separator system to flush captured sand into either a storage tank or evaporation pool. From the sand trap, flowback is sent to the separator, which reclaims up to 89% of natural gas and other hydrocarbons from the mixture. From there, gaseous components are sent to a dehydrator and then pumped into the supply line, while liquid hydrocarbons are sent to a condenser and then stored in barrels for shipment to a fuel processing plant.^[1]

All in all, the combination of reclaimed gas and liquid fuels may exceed $100,000 in worth depending on current fuel prices and the well, but the initial $500,000 price tag and maintenance costs for the REC machinery are prohibitive to many oil and gas companies.^[1]

It is our hope that the development of bacteria with the capability to convert methane to methanol will create a new avenue of REC technology. Given that the VOC's contained in flowback are 95% methane, the conversion of methane to methanol may eliminate the need for the gas extraction component of REC without considerable loss of product. Increases in methanol concentration will increase the yield of condensates in the flowback, and the removal of gas processing components will decrease the capital costs of REC technology, potentially making REC economically viable for thousands of additional gas wells across the US and abroad.

References

1. Coufal, D. E., Blazyk, J. L., Whittington, D. A., Wu, W. W., Rosenzweig, A. C., & Lippard, S. J. (2000). Sequencing and analysis of the Methylococcus capsulatus (Bath) soluble methane monooxygenase genes. European Journal of Biochemistry, 267(8), 2174-2185.

2. A. Marti-Renom, A. Stuart, A. Fiser, R.Sanchez, F. Melo, A. Sali. Comparative protein structure modeling of genes and genomes. Annu. Rev. Biophys. Biomol. Struct. 29, 291-325, 2000.

3. Murrell, J. C., Gilbert, B., & McDonald, I. R. (2000). Molecular biology and regulation of methane monooxygenase. Archives of microbiology, 173(5-6), 325-332.

4. Pandey, V. C., Singh, J. S., Singh, D. P., & Singh, R. P. (2014). Methanotrophs: promising bacteria for environmental remediation. International Journal of Environmental Science and Technology, 11(1), 241-250.

5. West, C. A., Salmond, G. P., Dalton, H., & Murrell, J. C. (1992). Functional expression in Escherichia coli of proteins B and C from soluble methane monooxygenase of Methylococcus capsulatus (Bath). Journal of general microbiology, 138(7), 1301-1307.