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Bioremediation: using microorganisms to clean up the environment

Microorganisms are known for their ability to adapt to any environment. We can find them in the most hazardous places on Earth. Their invisible work has led to visible results ― terraforming the planet billions of years ago and converting it into the viable green world that is today. Their ability to utilize and adapt to any available substrate in order to gain energy kept the balance in the ecosystem until humans become dominant species. Since the industrial revolution, human activity has produced a broad range of novel substances to which microorganisms can naturally adapt. The problem is that biodegradation can’t keep pace with the amount of substances being produced. Thankfully modern science offers a technology which employs microorganisms’ adaptability. It is called bioremediation.

What is Bioremediation? 

Bioremediation is a biotechnology procedure, in which microorganisms adapted to degrade pollutants from a contaminated site are stimulated to achieve a better biodegradation rate by enrichment with fertilizers and/or oxygen. Another variation of the technology is introducing microorganisms adapted in a laboratory into the contaminated site. In recent years, scientists have bypassed the adaptation steps microorganisms take by creating microorganisms which are genetically modified using integrating genes necessary for biodegradation of a specific contaminant. Microorganisms involved in the process aren’t only bacteria, but archaea, microalgae, and fungi. The practice poses minimal risk to the environment because after the substrate-contaminant is removed, the microorganisms can no longer survive and the process is cost effective. In situ bioremediation is the most common form of this process. However, instead of treating the contaminated place in its natural environment, bioremediation could also be done ex situ, by excavating pollutants from polluted sites and subsequently transporting them to another site for treatment.

The idea of employing microorganisms in waste management is not as new as one may think. It was used in ancient Rome wastewater treatment facilities. To fulfil their water supply needs, ancient Romans built aqueducts which led to excessive amount of wastewater. This problem was solved by the construction of a sophisticated sewage system – the Cloaca Maxima – where water was drained and cleaned by natural biodegradation. The process was slow and inefficient, but demonstrated nature’s potential to degrade waste substances.

Image credit: In situ bioremediation by Lidiya Angelova. Author owned.

Years later, the same process was employed by George M. Robinson, who developed modern bioremediation in the 1960s. He was a curious petroleum engineer, working for a petrol company in Santa Maria, California. Robinson mixed bacterial cultures with petroleum products and figured out that they could be a potential “cure” for the numerous oil spills, and to help improve the management of waste. He was able to collect enough evidence which convinced the local authorities and public to apply his findings in practice. This led to the implementation of bioremediation for preventing environmental disaster, such as cleaning the British passenger ship the Queen Mary’s fuel storage tanks before her “retirement” as a tourist attraction in Long Beach California in 1967. He later helped design the first large-scale microbial clean-up of an oil spill. California’ s large oil and tourism industry was an enormous burden for the environment, and Robinson’s development of bioremediation assisted to reduce its impact. His work didn’t go unnoticed by the scientific community, and in 1975 Ananda Mohan Chakrabarty ‒ a microbiologist working for General Electrics – designed the first genetically engineered oil degrading bacterium, from the genus Pseudomonas.

In addition to the successful decontamination of oil spills, which have a long-term impact on the health of ecosystems, this technology has countless other applications, from the recovery of coal or metal mines, to environmentally friendly disposal of radioactive waste. BTEX compounds (benzene, toluene, ethylbenzene, and xylenes) are toxic derivates from the oil industry which often end up in the groundwater. Bacteria and archaebacteria species have bioremediation potential which could help break them to less harmful substances.

Recent studies have shown the potential of microorganisms to decrease the environmental impact of landfills which are suffocating the land near metropolises. Even human carcinogens like vinyl chloride can’t stop bacteria. Their ability to degrade it could be implemented in decontamination of groundwater.

Despite its advantages, bioremediation is not well known amongst the people who could benefit from it and those who can make important decisions regarding environmental issues ‒ legislators, regulators, politicians and other influential figures outside the environmental science world.

Scientists and science communicators can help fill the gap by spreading awareness about the abilities of microorganisms to clean up our environment.

Featured image credit: Earth sustainability by Ann Ca. CC0 via Pixabay.

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