For decades, pollution clean-up has relied on expensive technologies, large-scale engineering projects, and chemical treatments. Now, scientists are exploring a different ally in the fight against contamination: bacteria.
According to Nature, researchers are engineering microbes to metabolise certain pollutants, ranging from petroleum products and plastics to corrosive industrial chemicals. They anticipate that these microorganisms can eventually be used in large-scale remediation efforts to clean contaminated soils, waterways, and coastal environments.
While this concept might sound futuristic, it is based on a well-established biological reality: bacteria have been evolving for billions of years and have repeatedly adapted to new environmental challenges, enabling some species to metabolise compounds once thought to be highly resistant to biological degradation.
Recent research in Nature suggests that synthetic biologists are speeding up this process by redesigning microbes so they can break down pollutants more efficiently in the lab than naturally occurring strains.
Oil Spills to Plastic Waste
While microorganisms have been employed to help manage pollutants since, say, after a large oil spill where natural bacteria contributed to the breakdown of hydrocarbons in contaminated waters, the capabilities of these microbes are rapidly being amplified through engineering. A study of Ideonella sakaiensis, a bacterium identified by researchers in Japan in 2016, which uses a set of enzymes to break down polyethylene terephthalate (PET), a common plastic, is only the tip of the iceberg.
The original discovery, published in Science, showed that the bacterium could use PET as a food source. Research has helped scientists understand the structure and reaction mechanisms behind PET-degrading enzymes, opening the door to engineering faster and more efficient versions.
This information enables scientists to engineer faster and more efficient PET-degrading variants of this enzyme and even explore applying a similar concept to plastics commonly used in bottles, food packaging, and other major sources of landfill waste.
Toxic Chemicals to Overcome
Beyond plastics, bacteria are being developed to help degrade hazardous industrial chemicals that have historically resisted breakdown due to their strong chemical bonds. These perfluoroalkyl and polyfluoroalkyl substances (PFAS, or "forever chemicals") are found in products like Teflon-coated cookware, waterproof clothing, and fire-fighting foam; due to these strong bonds, they last for decades.
Researchers reported the formation of degradation products, though scientists continue to study the environmental impacts and toxicity of these by-products. As evidence of PFAS contamination increases in water systems and ecosystems around the world, scientists hope that biologically assisted pollution breakdown will serve as a supplement to existing cleaning technologies, preventing a long-term health crisis.
Engineering Nature
The recent advent of high-precision tools to manipulate the DNA of microbes allows scientists to program their behavior more effectively than before, as shown by recent work reported in Nature. Many researchers are now designing microbes that can detect specific pollutants and, in some cases, move toward areas where those pollutants are concentrated.
Other teams are now experimenting with the engineered cohabitation of different bacteria, which would be programmed to work together to each take a step in the degradation process. According to Nature, Ludmilla Aristilde, an environmental engineer at Northwestern University, is among the researchers seeking solutions with this technology while minimizing environmental impact.
Promise, Tempered with Caution
These findings offer tremendous promise, though scientists remain cautious, acknowledging that translating laboratory breakthroughs to real-world pollution problems is a substantial challenge due to differences in environmental conditions, such as temperature and nutrient availability.
Moreover, the regulatory and ecological ramifications of releasing engineered microbes are far-reaching and necessitate extreme caution before wide-scale implementation. Because of these issues, many now anticipate that engineered microbes will simply become a component of an integrated pollution mitigation strategy.
Despite the cautionary notes, the science has advanced considerably: the idea of bacteria capable of degrading plastics or certain PFAS compounds would have seemed unlikely only a few decades ago. Today, scientists are continuing to improve these abilities in laboratories worldwide, and future clean-up efforts may rely on a mix of biological tools.
