The result: within 16 hours, PHL7 caused the PET to decompose by 90 percent; in the same time, LCC managed a degradation of just 45 percent. "So our enzyme is twice as active as the gold standard among polyester-cleaving hydrolases," Sonnendecker explains. For example, PHL7 broke down a plastic punnet?"the kind used for selling grapes in supermarkets?"in less than 24 hours. The researchers found that a single building block in the enzyme is responsible for this above-average activity. At the site where other previously known polyester-cleaving hydrolases contain a phenylalanine residue, PHL7 carries a leucine.