Trace additive could help compostable PLA plastics break down in backyard bins

Currently, only 18% of the U.S. population has access to industrial composting facilities

MINNEAPOLIS / ST. PAUL (07/27/2026) - Researchers at the University of Minnesota Twin Cities have developed a new strategy that could help compostable plastics break down more quickly under everyday composting conditions, reducing the need for specialized industrial facilities.

The paper was published in ACS Central Science, a peer-reviewed scientific journal that publishes the most compelling discoveries with exceptional impact in the physical and life sciences in which chemistry has a central role.

Polylactide, known as PLA, is a renewable and compostable plastic that can be found in everyday products such as compostable food packaging, cups and cutlery. While these items are labeled “compostable,” access to suitable industrial compost facilities are scarce. 

“Compostability of these plastics is largely limited to industrial composting conditions,” said Marc Hillmyer, McKnight Presidential Endowed Chair in the Department of Chemistry and co-senior author of the paper. “Unfortunately, only about 18% of the U.S. population has access to industrial composting facilities. As a result, many PLA products ultimately end up in landfills upon disposal.”

Researchers found that incorporating a trace amount of 2-sulfobenzoic acid cyclic anhydride (SAn) dramatically accelerates the hydrolytic degradation of PLA. When exposed to moisture over time and under composting temperatures, SAn generates acidic compounds that help break the plastic’s molecular bonds from within. In effect, the additive acts as a “masked acid” that remains dormant during normal use but activates under the combined conditions of moisture, temperature and time found during composting.

Because the process requires as little as 0.01% of the additive, the plastic retains its strength and durability during everyday use. The additive also enables PLA to break down under milder, lower temperature conditions than those required by industrial composting facilities.

“While biorenewable and degradable plastics are a great step forward, they lose their environmental value if they just sit in a landfill,” said Christopher Ellison, Professor in the Department of Chemical Engineering and Materials Science and co-senior author on the paper. “By introducing this new additive, it could make more sustainable and home compostable packaging a reality for the average household.”

Next, the researchers plan to test this method on a wider variety of commercial plastics. They are also conducting rigorous ecotoxicity tests to ensure the plastic containing the additives integrates back into the soil, remaining safe for the environment and local ecosystems.

Read the full paper entitled, “Dramatic Enhancement in Polylactide Hydrolysis and Biodegradability Utilizing Low Levels of Organic Anhydrides As Masked Acids,” on the ACS Publications website.