When Dr. Shiran Barber-Zucker joined the lab of Prof. Sarel Fleishman as a postdoctoral fellow, she chose to pursue an environmental dream: breaking down plastic waste into useful chemicals. Nature has clever ways of decomposing tough materials: Dead trees, for example, are recycled by white-rot fungi, whose enzymes degrade wood into nutrients that return to the soil. So why not coax the same enzymes into degrading man-made waste? Barber-Zucker's problem was that these enzymes, called versatile peroxidases, are notoriously unstable. "These natural enzymes are real prima donnas; they are extremely difficult to work with," says Fleishman, of the Biomolecular Sciences Department at the Weizmann Institute of Science.