A bacterium isolated from kimchi may assist in kimchi bacterium nanoplastic removal from the gut, according to research from the World Institute of Kimchi (WiKim), a government-funded research institute under South Korea’s Ministry of Science and ICT. The claim rests on laboratory adsorption tests and a germ-free mouse study: real data, but a long way from a human clinical trial.
The strain in question is Leuconostoc mesenteroides CBA3656, a lactic acid bacterium drawn from kimchi. Researchers led by Drs Se Hee Lee and Tae Woong Whon at WiKim set out to measure how well it binds to polystyrene nanoplastics under conditions that mimic the human intestine. That distinction (standard lab conditions versus simulated gut conditions) turns out to be where the interesting result sits.
What the adsorption experiments actually showed
Under standard laboratory conditions, strain CBA3656 achieved an adsorption efficiency of 87% against polystyrene nanoplastics. That sounds impressive, but it was not dramatically different from the reference strain Latilactobacillus sakei CBA3608, which came in at 85%. The more telling comparison came when both strains were placed under simulated human intestinal conditions. CBA3608’s adsorption rate collapsed to 3%. CBA3656, by contrast, held at 57%. The researchers say this indicates the kimchi-derived strain can stably bind nanoplastics even in an environment resembling the gut.
Why that gap exists between the two strains under intestinal conditions is not explained in the published findings. That is not a criticism of the research (it is a reasonable next question for follow-up work) but it is worth noting that the mechanism behind the stability has not been characterised here.
The mouse model results and their limits
The more eye-catching numbers come from the animal experiments. Using a germ-free mouse model, the team found that mice administered strain CBA3656 showed more than a twofold increase in nanoplastics detected in faeces, compared with a control group that received no probiotics. Both male and female mice were included. The researchers interpret this as evidence that the probiotic may be binding nanoplastics in the intestine and helping carry them out of the body.
That is a plausible mechanism. It is also, at this stage, a hypothesis supported by a mouse study rather than a demonstration in humans. Germ-free mouse models are a useful tool precisely because the absence of a resident microbiome makes it easier to isolate a variable, but they are not a direct proxy for what happens in a human gut already colonised by hundreds of bacterial species. Whether CBA3656 would retain its binding capacity in that more competitive environment is an open question the study does not answer.
Nanoplastics, defined here as particles smaller than 1 micrometre, enter the body through food and drinking water. Their size means they can potentially cross the intestinal barrier and accumulate in organs including the kidneys and brain. Biological strategies to reduce that accumulation are, as the researchers acknowledge, at an early stage.
Where this sits in the published literature
The study was published in Bioresource Technology, which carries an Impact Factor of 9.0 and is ranked first in the field of Agricultural Engineering, according to EurekAlert!. The first author is Jisu Lee, PhD; the corresponding authors are Tae Woong Whon, PhD and Se Hee Lee, PhD.
‘Plastic pollution is increasingly recognised not only as an environmental issue but also as a public health concern,’ said Dr Se Hee Lee. ‘Our findings suggest that microorganisms derived from traditional fermented foods could represent a new biological approach to address this emerging challenge.’
That is a reasonable framing of what has been shown: a promising in-vitro and animal result, published in a peer-reviewed journal, pointing to a direction worth pursuing. The claim that kimchi bacterium nanoplastic removal is a proven or deployable health intervention is not what this study establishes. What it does establish is that CBA3656 binds polystyrene nanoplastics more robustly than its comparator under gut-like conditions, and that the signal carries through to faecal excretion in mice. The team says it will continue to develop kimchi microbial resources for public health applications. Human trials, if they follow, will be the point at which the practical significance of that twofold mouse result can actually be assessed.
