Engineered biodegradable plastics disappear in the deep ocean

Researchers from Japan have developed a novel biodegradable plastic, called LAHB (lactate-based hybrid polymer), that can degrade in the deep ocean—addressing a major environmental challenge where conventional biodegradable plastics like polylactide (PLA) fail. While PLA is widely used and compostable at high industrial temperatures, it does not break down in marine environments because marine bacteria lack the enzymes to recognize and degrade its molecular structure. In contrast, LAHB combines lactic acid from PLA with 3-hydroxybutyrate (3HB) from polyhydroxybutyrate (PHB), a naturally occurring polyester that marine microbes can digest. This hybrid polymer maintains material strength while being susceptible to microbial degradation in deep-sea conditions. The breakthrough stems from engineering Escherichia coli bacteria to biosynthesize LAHB by inserting genes for a lactate-polymerizing enzyme, enabling the production of a plastic that balances durability with biodegradability. Marine bacteria have evolved depolymerase enzymes that