World Environment Day 2025 is a timely reminder of the importance of protecting our ecosystems. Among the many innovative solutions scientists and environmentalists are exploring, bioremediation and plastic-eating bacteria are leading the way in cleaning up pollutants like plastics, oil, and waste. These microbial solutions are becoming more relevant than ever as the planet grapples with the consequences of pollution and climate change.

What is Bioremediation?

Bioremediation is the process of using living organisms, such as bacteria, fungi, and plants, to clean and recover polluted environments. As a natural and sustainable method of pollution management, it aligns with the goals of World Environment Day 2025.

The environment supports life by providing resources and maintaining natural balance through diverse ecosystems. Microorganisms are vital to these ecosystems, as they help break down organic matter, recycle nutrients, and play an important role in bioremediation.

Biotechnology, the use of biological processes and organisms to solve problems, is widely used in environmental science and agriculture to promote sustainability^[1][2]. Bioremediation uses microorganisms, plants, or their enzymes to restore a polluted ecosystem to its original state^[3]. These organisms may be native to the contaminated area or introduced from elsewhere to degrade or detoxify pollutants^[4]. Common pollutants include pesticides, plastics, waste oils, and biological waste,ll of which contain harmful components that are discharged into the air, soil, or water, causing adverse effects.

Plastic-Eating Bacteria

Plastic-eating bacteria offer a promising solution to the growing problem of plastic waste. These microorganisms break down synthetic polymers like polyethylene terephthalate (PET), commonly used in water bottles and food packaging.

PET is widely used for its durability and versatility, but its increasing use and improper disposal have led to serious environmental issues^[5]. Recycling and bioremediation from plastic-eating microbes are essential for mitigating these issues^[5][6].

In 2016, researchers identified Ideonella sakaiensis, a naturally occurring Gram-negative bacterium capable of producing the PETase enzyme, which breaks down PET into mono (2-hydroxyethyl) terephthalate (MHET). The bacterium also releases a second enzyme, MHETase, which further degrades MHET into its basic components -terephthalic acid and ethylene glycol^[7]. These smaller molecules are then used by the bacterium as sources of carbon and energy.

Radiation-Resistant Bacteria

Radioactive isotopes, along with ionising and non-ionising radiation, are used in nuclear power generation, food preservation, water sterilisation, and crop improvement in agriculture. Their use is widespread and necessary across many industries. However, ongoing exposure or improper disposal of this waste into the environment can be harmful to living organisms[8].

Deinococcus radiodurans, a Gram-positive bacterium, can withstand abnormally high radiation levels due to its powerful antioxidants and increased DNA repair process. As a result, it is becoming the preferred organism for engineering solutions radioactive waste

bioremediation[9]. This radiation-resistant bacterium can be genetically altered to express different genes and/or enzymes to precisely target pollutants within radioactive waste[8][10]. Mercury is a commonly found pollutant in nuclear waste. In modified Deinococcus, the enzyme Mercuric reductase is added, allowing this species to eliminate toxic ionic mercury residues by reducing the inorganic compound Hg(II) to a less toxic form[8].

Oil Spill Cleaning Bacteria

Oil spills are devastating to marine ecosystems, but oil-degrading bacteria offer a bioremediation solution by naturally degrading harmful hydrocarbons.

A well-known example is Alcanivorax borkumensis, a marine bacterium that thrives in oil-contaminated habitats by using hydrocarbons as its main energy source. It rapidly breaks down alkanes -key components of crude oil, and often becomes dominant in affected areas. Research published in Nature Reviews Microbiology says A. borkumensis plays a significant role in the natural reduction of marine oil pollution^[11], thanks to its enzyme systems that convert oil compounds into less harmful substances. Additionally, native marine microbial ecosystems work collectively when oil spills occur to degrade hydrocarbons, reducing environmental damage.

While bioremediation offers a sustainable way to tackle environmental pollution by harnessing the natural processes of microorganisms, plants, and fungi, it does come with certain limitations. Sometimes, it can produce byproducts that are more toxic than the original pollutants, and not all contaminants are easily biodegradable, meaning other remediation methods might be needed. However, as biotechnology continues to evolve, combining bioremediation with genetic engineering holds greater promise for addressing environmental challenges and creating a cleaner, healthier future.

References

1. https://doi.org/10.1016/B978-012373944-5.00150-4

2. https://doi.org/10.1007/s00253-002-1024-6

3. https://doi.org/10.1016/B978-0-443-15232-0.00015-1

4. https://doi.org/10.1016/B978-0-323-89937-6.00013-9

5. https://doi.org/10.1016/j.cscee.2024.100673

6. https://doi.org/10.1007/s10311-021-01384-8

7. https://doi.org/10.1038/s41587-024-02401-1

8. https://doi.org/10.1016/B978-0-323-90452-0.00037-2

9. https://doi.org/10.4161/bbug.3.1.18878

10. https://doi.org/10.1016/j.crmicr.2022.100153

11. https://doi.org/10.1038/nrmicro2671