Bacteria found in fermented foods like kimchi could be a powerful tool in the fight against plastic pollution. Researchers have discovered that a specific bacterium, isolated from kimchi, can bind to nanoplastics in the gut and facilitate their excretion from the body. This finding not only highlights the potential of fermented-food microbes as natural plastic binders but also opens up new avenues for addressing plastic pollution and its associated health concerns.
The Kimchi Microbe's Plastic-Binding Abilities
The bacterium in question, Leuconostoc mesenteroides, commonly found in fermented foods, utilizes a process called biosorption to trap pollutants. Chemical groups on its outer layers enhance its ability to bind to plastic, ensuring stable contact. In laboratory tests, this kimchi-derived bacterium outperformed a comparison strain, binding 87% of nanoplastics before digestion was simulated, compared to 85% for the comparison strain.
Testing in Mice
To further validate the effectiveness of this bacterium, researchers conducted experiments using germ-free mice, which lack their natural gut microbes. When these mice were given the kimchi-derived bacterium, they produced more than twice as many nanoplastics in their feces compared to untreated controls. This suggested that the bacterium was effectively capturing and removing plastic particles from the intestine before they could enter the body.
The Importance of Size
Nanoplastics, due to their small size, can sometimes cross biological barriers and potentially linger in the body. Research has shown higher plastic concentrations in brain samples compared to liver or kidney samples during autopsies. While this does not prove harm, it emphasizes the importance of finding safe methods to prevent plastic particles from entering the body.
The Role of the Intestine
The intestine is a critical site for plastic particle exposure, as it is where these particles meet digestion, mucus, and the cells lining the body. Edible microbes, such as those found in kimchi, offer a promising approach to intercepting contaminants at the entry point, preventing them from spreading further.
Kimchi's Historical Context
Kimchi, a traditional Korean side dish, has been a part of people's diets for generations. The use of lactic acid bacteria in kimchi fermentation provides a large pool of food-safe candidates for further research. The long history of consuming fermented-food microbes reduces the risk of introducing harmful strains, making kimchi a valuable resource in the quest for plastic-binding bacteria.
Limitations and Future Directions
While the study shows promising results, there are limitations to consider. The test plastic used was polystyrene, and further research is needed to determine if the same strain can bind to other common polymers. Additionally, human digestion is more complex than lab simulations, and longer studies are required to assess the impact on absorption, inflammation, and gut ecology.
Despite these limitations, the study highlights the potential of fermented-food microbes as a natural solution to plastic pollution. The next steps include screening fermented foods for stronger binders and conducting careful human studies to ensure safety and effectiveness.
In conclusion, the discovery of a kimchi bacterium's ability to bind and remove nanoplastics from the gut is a significant development in the field of plastic pollution research. It offers a concrete and natural approach to preventing plastic exposure, which is crucial in addressing the growing public health concern of plastic pollution.
