Building Cellular Machines to Solve Environmental Crises
Mounting environmental challenges force scientists to look to a new hero; bacterial cells.
The Exxon Valdez oil spill that occurred in 1989 remains one of the most infamous climate disasters in history. An oil tanker’s ruptured hull spilled nearly 11 million gallons of crude oil into Alaska’s Prince William Sound. The outcome of this spill was devastating, and the cleanup efforts dragged on for four summers before being called off. However, the according to the Exxon Valdez Oil Spill Trustee council, the cleanup was incomplete and many beaches remain oiled today.
One tactic used in the Exxon Valdez cleanup was bioremediation. This is a strategy touted by the EPA which uses “naturally occurring organisms to break down hazardous substances”. In the case of Exxon Valdez the bioremediation used fertilizers to aid already present bacteria in breaking down the hydrocarbons in the spilled oil. This strategy, though effective, works slowly and stands to be greatly improved by synthetic biology. The largest component of crude oil are hydrocarbons. It is very feasible to create an organism which breaks hydrocarbons down to make them less harmful to the environment and easier to remove. Perfecting and tweaking this process, to innovate in ways nature could not on a timeline not allowed by evolution, is a promising solution to this and many environmental challenges.
The earth is facing enormous environmental changes and challenges. According to the National Center for Atmospheric Research, NCAR, 1983–2012 was the warmest 30 year period in the past 1,400 years. While global warming and its effects have drastically increased in the recent past, so have innovations to combat and prevent these negative changes. In those past 20 years a new branch of scientific discovery has emerged, one that scientists are now turning to in order to solve and prevent some of the issues of climate change. This unlikely environmental hero comes in the form of synthetically engineered cells.
Imagine being able to control a cell, telling it exactly how to function and what outputs to produce. This is what synthetic biology allows scientists to do, and it is possible that these designer cells will revolutionize the way scientists combat the changing climate. Synthetic biologists write new genetic sequences and implant them into to cells, usually empty bacterial cells such as E. coli, so that they perform a set of discrete tasks. This method of precise genetic control is becoming a leading strategy for scientific innovations to combat climate change.
The beginnings of synthetic biology came from the pharmaceutical industry. Before the 1980’s, pharmaceutical production of insulin relied on isolating the substance from cow and pig pancreases. This method, though it produced a lifesaving medication for diabetics, was expensive, environmentally damaging, and inefficient. Scientists searched for a more efficient way to produce this imperative medication. By implanting the genes which code for insulin into E. coli cells, scientists at Eli Lilly & CO were able to create the first synthetically derived insulin, Humulin, which earned FDA approval in 1982. This method, though technically genetic engineering, ushered in a new era of genetic manipulation and harnessing the power of cells for innovation.
Assembling a genetic code is like placing beads on a string, each bead a telling the cell to do or produce something different. Synthetic biology allows scientists to create unlimited combinations of these genetic beads, harnessing cellular power to innovate nearly every field of scientific discovery. Synthetic biology is used to produce medications, to create cellular calculators, and to innovate systems of designed synthetic functioning. Its limitless applications allow scientists to address problems from non-traditional methods, and to combine engineered solution with biologically viable ones.
Jim Dixon, a Massachusetts Master Teacher and Presidential Distinguished teacher who had been bringing synthetic biology to high school students through specialized summer programs in partnership with MIT speculated that “there will be many partnerships [between synthetic biology labs and companies because] there is a lot of money to be made by seeking alternate sources to limited resources”. Three ways that this is being applied to the environmental crises are greener production of historically raw materials, production of energy and fuel sources, and using engineered cells to clean up oil and chemical spills and abate their effects.
Natural rubber is used in everything from tires to rain boots, gloves, and erasers. According to the Scientific American, 70% of this rubber is used to manufacture tires and the demand is only growing. Rubber is harvested from Hevea brasiliensis trees through the process of tapping. This process is generally thought of as having low environmental impact, but damage to the trees is common and when demand for rubber is high the tree is sometimes sacrificed for faster rubber production. Additionally, the scarcity and importance of this natural resource places the rubber industry in a precipitous place. A single leaf blight was able to wipe out the entire industry in Brazil, where the rubber tree species originated. The brunt of natural rubber production has now moved to Southeast Asia where similar blights and the demands of deforestation further threaten the industry. This is the perfect opportunity to put synthetic biology to the test in a large and important market.
The Hevea tree produces an enzyme, isoprene synthase, which produces the raw ingredient of natural rubber, isoprene. This is an enzyme that can easily be reproduced inside of any bacteria and has. Amyris, a California based synthetic biology company announced in 2011 that it would begin producing isoprene for Michelin tires. It was then announced in 2014 that another synthetic biology company, Braskem, would be joining the collaboration. While none of these tires have hit the roads yet, these announcements mark a big shift in moving the science from the lab to the marketplace
Another exciting area where synthetic biology is being applied to environmental issues is the production of biofuels. Labs across the world are racing to design and perfect an easily produced and utilized synthetic biofuel because of the major market potential for such a product. One such lab is the Yazdani at the International Centre for Genetic Engineering and Biotechnology in New Delhi, India. They are working to design a strain of E. coli that can produce batches of ethanol. Although ethanol has been celebrated as a semi renewable fuel that can be easily obtained from sources like corn, a study published in Nature found that ethanol fuels can increase ground-level ozone pollution to dangerous levels. It is important to consider what the implications of different biofuel engineering strategies are, if labs are working to create products such as ethanol this fits into the current fuel industry which worsens the pollution and climate change the earth is facing. Perhaps, labs should be looking into solutions which work outside this existing structure, but provide fuel in way that does not worsen climate change. Joule, a lab in Cambridge, Massachusetts has created an organisms which converts sunlight and waste CO2 into diesel fuel. Innovations such as this show that synthetic biology’s use for creating greener and more effective fuels, though just starting out, have incredible potential.
These developments hold great promise, not only to advance the scientific understanding of the synthetic biology, but to provide innovative ways to combat the earth’s changing climate. As the world looks to a future threatened by the effects of humanity’s damage to the climate there is also a future where bright scientific minds can creatively address these problems.
