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Scientists Develop Method to Transform PET Plastics and Agricultural Waste into Ingredients Used in Experimental Production of Protein-Rich Cookies.
Researchers from Southern Illinois University in the United States are testing an unusual way to utilize discarded plastics: breaking down molecules found in PET and using genetically modified microorganisms to convert them into components that can be included in food.
The team, led by Sandhya Jayasekara, has already produced experimental protein-rich cookies from this method, but the product is still awaiting health authorities’ approval to proceed with taste tests.
The approach does not involve grinding packaging and adding it directly to the recipe. Instead, the process chemically transforms the waste before delivering it to yeasts, which act as small biological factories. The goal is to capture the carbon present in the plastic and reconstruct it into molecules with different functions.
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The research was published on August 24, 2026, in ACS.
PET Bottles as One of the Raw Materials
The work utilizes PET, or polyethylene terephthalate, a polymer widely used in water and soda bottles. Its composition contains carbon-rich molecules, which are also present in food.
This connection led the team to explore a different use for waste that would normally go to conventional recycling or disposal.
Along with plastics, the scientists are working with agricultural biomass, including discarded stalks and leaves from corn plants. Thus, two sources of waste enter the same conversion system.
Professor Lahiru Jayakody explains that the project began with the search for ways to recycle plastic and produce higher-value items. The potential to transform this carbon into food emerged later as a new direction for the research.
Water, Oxygen, Pressure, and Heat Break Down the Waste Before the Yeasts
The first step uses a procedure called oxidative hydrothermal dissolution. Water and oxygen are subjected to high temperatures and pressure to decompose resistant structures into smaller fragments.
Only after this transformation do microorganisms enter the process.
Jayasekara has programmed different types of yeast, including standard baking yeast, to consume the resulting compounds and convert them into substances such as proteins, vitamins, and aroma compounds.
The logic is similar to the use of microorganisms already established in other areas of biotechnology. Yeasts can receive genetic instructions to produce specific molecules, functioning as living production systems.
Mixture Also Receives Fiber, Starch, and Sweetener
The ingredients produced by microorganisms do not exit the process already in the form of a cookie.
After the biological stage, the researchers add fiber, starch, and sweetener. The resulting preparation is then sent to a 3D printer, which shapes the protein-rich cookies.
The team sees this format as a way to make the technology easier to understand and use. Instead of presenting just a laboratory-produced compound, the scientists aim to demonstrate how it could appear in a recognizable food.
Application Also Considered for Resource-Limited Situations
The proposal is not limited to recycling. The researchers believe that the ability to produce nutrients from waste could be useful in disaster-stricken areas or in future crewed space missions, where food availability and resource reuse become critical issues.
The team members themselves tasted the experimental cookies and found them palatable. Preliminary evaluations of aroma also received positive feedback, although many participants indicated they would consume the product primarily in situations where alternatives are scarce.
However, this stage does not mean that the cookies are cleared for commercial consumption. The research still depends on approval from health authorities to conduct formal taste tests.
The scientific advancement is, for now, in the conversion process: instead of treating plastics solely as waste to be eliminated, the team aims to transform some of its components into raw materials for nutritionally valuable molecules.
