Danielle Milankov
Concern for the environment is one of the most prevalent issues of our time. From pollution due to fossil fuel emissions to the chemical runoff from agricultural fertilization, there is no shortage of environmental side effects caused by human activity. Despite these consequences, we may be able to remedy our behaviour by looking to nature to find new, sustainable techniques and technologies. In fact, scientists and innovative companies have recently looked into this concept to come up with solutions to pollution by tapping into the potential of our microscopic cohabitants — micro-organisms, commonly called microbes.
In 2010, the infamous Deepwater Horizon oil spill released 4.9 million barrels of oil (about 779 million litres) into the Gulf of Mexico. Alongside the clean-up efforts, researchers found that several native bacteria, including Alcanivorax borkumensis, were consuming and degrading the spilt oil. Although the exact amount of oil consumed by the bacteria is uncertain, estimates suggest that the microbes helped remove as much as 50% of the oil.
Photo of the oil spilt at the Deepwater Horizon oil well. (Image Source: The New Yorker)
The discovery and usage of bacteria and other microbes like Alcanivorax borkumensis is part of an environmental clean up technique called bioremediation. Bioremediation is the process of using microbes to remove pollutants from environments, either by enhancing the pre-existing microbes or by adding new ones. In particular, it uses the natural processes of the bacteria to break down contaminants into harmless by-products, which efficiently removes all pollutants without affecting the environment. The usage of microbes in bioremediation has been put to good use by companies such as TerraStryke Products LLC, which remediated a former textile factory in Hamilton by reducing toxic pollutants like tetrachloroethylene by 98%. TerraStryke uses the bacterial enhancement method by adding nutrients to the polluted sites and creating other favourable conditions to increase bacterial activity and efficiency in contaminant degradation.
Furthermore, additional research has been done on how bacteria can remediate soil and water contaminated with heavy metals from mining operations. In 2017, at an abandoned gold mine in Manitoba’s Nopiming Provincial Park, researchers discovered that a group of bacteria called aerobic anoxygenic phototrophs have the ability to reduce toxic mine tailings into less toxic forms. These bacteria may be deployed to help restore mining sites, further demonstrating the power of microbes in dealing with human pollution.
The application of bacteria is not limited to cleaning up our pollution; microbes can also be used to help reduce the production of pollution as well. Similar to fossil fuels, biofuels are combustible hydrocarbon fuels. However, unlike fossil fuels, biofuels produce less greenhouse gases when burnt and they primarily come from plant matter, which makes them renewable. One usage of biofuels is the addition of the biofuel ethanol to gasoline and diesel, which creates a fuel mixture that reduces the amount of pollutants released when it is burnt by an engine. These mixtures have already been implemented by specialized cars called Flexible Fuel Vehicles (FFV), which have engines capable of using ethanol-gasoline mixtures containing up to 85% ethanol. Such examples of FFVs include cars like the Ford Explorer and Ford F-150. As of 2017, there were 21 million FFVs on the road in the United States alone. Where microbes come into this picture is in the production of ethanol.
The production of biofuel requires large amounts of plant matter that demands greater pesticide and fertilizer use, causing further environmental concerns. Bacteria can help alleviate these concerns by using their biological processes to directly produce sugar from nutrients. These nutrients can either come from plant matter or from fertilizer. This sugar can then be fermented into ethanol by another type of microbe: yeast. The viability of bacterial sugar production has been investigated by the company HelioBioSys Inc. in conjunction with Sandia National Laboratories in the United States, which has found that a microbe called cyanobacteria can produce about four to seven grams of sugar from one litre of biomass — a much greater feat than that of its competitor, algae, which only produced one gram. With this capability, cyanobacteria may be able to supply the eco-friendly biofuel supplement to fossil fuels.
Cyanobacteria under a microscope. (Image Source: ThoughtCo.)
The category of biofuels also includes the process of genetically modifying bacteria to produce the same hydrocarbons used in gasoline and other fossil fuels. In 2013, a report from the National Academy of Sciences found that certain strains of the bacterium Escherichia coli (E. coli) could be completely genetically engineered to convert sugar into a diesel-like oil. Although this discovery may theoretically provide a renewable replacement for fossil fuels, it does not address the issue of the pollution that would still result from using this bacteria-created hydrocarbon fuel. This consideration also applies to the ethanol-fossil fuel mixtures; in helping to produce renewable biofuel supplements, microbes are still prolonging fossil fuel usage and therefore pollution. Unlike bioremediation, biofuels do not help remedy human pollution; they only help to mitigate it. This observation leads one to wonder, what is the best use of the power of microbes?
Perhaps microbes are most beneficial in removing pollution when they are acting naturally in their native habitat. For example, there are many beneficial microbes that are essential to plant health. The most well-known example is the group of soil bacteria belonging to the genus Rhizobium, which associate with plant roots to help provide them with key nutrients such as nitrogen. Researchers have suggested that these plant-friendly bacteria could be used to supply greater amounts of nutrients to crops to increase their yields.
This plant-bacteria relationship is what the company Pivot Bio has been using to eventually replace synthetic fertilizers, which are often applied in excess and end up being released into the environment as greenhouse gases. Pivot Bio finds bacteria already present on farms, genetically enhances their original functionality to produce more nitrogen and reintroduces them to the farm, all in order to reduce the amount of fertilizer used while maintaining crop yields. Since 2019, over one million acres of crops in the United States have used Pivot Bio’s technology. This technique is remarkably similar to bioremediation, as both are using the microbe’s pre-existing function to help remove pollution and are not completely altering the microbe to prolong fossil fuel usage, as microbial biofuel production does.
The application of microbes holds great promise in helping to find environmentally-friendly solutions to pollution. However, the method in which microbes are utilized will determine how helpful they end up being to the environment. While bioremediation and the enhancement of bacteria to reduce synthetic fertilizer usage both hold the promise of reducing, and eventually eliminating, pollution from their respective sources, biofuels hold less promise in that regard. Still, these developments in microbe technology have shown that nature holds viable solutions to humanity’s pollution problem.
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