Overview

• Researchers from the microONE project exposed stool-derived gut cultures from five healthy donors to five common polymers at estimated human exposure levels.
• Exposed cultures showed consistently lower pH, indicating altered microbial metabolism compared with unexposed controls.
• Polymer‑dependent shifts were observed mainly within the Bacillota phylum, including changes across Lachnospiraceae, Oscillospiraceae, Enterobacteriaceae and Ruminococcaceae.
• Metabolomic profiles changed by plastic type, with reported alterations in valeric acid, 5‑aminopentanoic acid, lysine or lactic acid that corresponded with the pH drop.
• Some microbial patterns resembled those previously linked to colorectal cancer and depression, while overall bacterial cell counts remained largely unchanged and experts urged cautious interpretation.