Domestic researchers have developed a technology to create biodegradable plastic fibers using Escherichia coli. Plastics are not easily decomposed, causing significant harm to ecosystems and exacerbating environmental pollution as they originate from petroleum. The plastics produced by Escherichia coli decompose naturally, and since their raw material is organic matter obtained from living organisms, they have been evaluated as a sustainable production method.
A research team led by Professor Lee Sang-yeop from the Korea Advanced Institute of Science and Technology published these research results in the international academic journal "Nature Chemical Biology" on the 18th.
As of 2022, approximately 400 million tons of plastics were produced annually worldwide. Most of this is produced through petroleum-based chemical processes. Plastics are a major cause of environmental pollution since they do not decompose naturally. The raw material, petroleum products, emit greenhouse gases during production. Scientists are conducting research on synthesizing biodegradable plastics from microorganisms as an alternative.
Bacteria synthesize various polymer compounds to store nutrients. Polymer compounds are chain-like substances with repeated structures, similar to plastics. Until now, there have been studies on synthesizing synthetic fibers such as polyester using bacteria, but it has been difficult to create plastics similar to nylon, which is commonly used in clothing and footwear.
Nylon is a polymer linked by "amide bonds," similar to the amino acids that make up proteins. An amide bond refers to nitrogen attached to a carbon next to an oxygen with a double bond. In contrast, polyester is made up of ester bonds, where a carbon with a double bond to oxygen forms single bonds with other oxygen atoms in a chain. Nylon is stronger than polyester.
The research team modified the genes of Escherichia coli to produce polymers similar to nylon. The polyester amide (PEA) ultimately produced is primarily composed of polyester, but some portions included amide bonds similar to nylon. This resulted in a form that is intermediate between nylon and polyester. Professor Lee Sang-yeop noted, "Since nylon is a polymer made up of 100% amide bonds, further research is necessary to create plastics with identical properties using current technology."
The research team also conducted tests to produce PEA in actual large-scale culture systems beyond the laboratory. As a result, they confirmed the feasibility of mass production by producing approximately 55 grams of PEA per liter. Notably, the PEA created this time was similar to high-density polyethylene (HDPE), a plastic widely used for food packaging. The biodegradable plastics produced by Escherichia coli are likely to be utilized as eco-friendly food packaging materials in the future.
However, there are challenges that remain to be addressed before reaching the industrialization stage. The PEA produced by Escherichia coli has a large particle size, making it unable to pass through the bacterial cell wall. To obtain the plastic, the Escherichia coli must be destroyed. Purification processes are required, along with processes to create the desired shapes.
Professor Lee said, "So far, the production method of PEA using microorganisms costs more than petroleum-based plastic production, but it is expected that production costs can be gradually reduced through optimization processes."
References
Nature Chemical Biology (2025), DOI: https://doi.org/10.1038/s41589-025-01842-2