Irish and German researchers have discovered that the soil bacterium Pseudomonas putida can eat pyrolyzed oil from waste polystyrene to produce the biodegradable polymers PHA (polyhydroxyalkanoates). Kevin O'Connor of University College Dublin and colleagues there and in Germany have demonstrated that an engineered microbial strain can convert petroleum-based plastic waste into a reusable biodegradable form. O'Connor suggests that a similar process might be used to convert other types of discarded plastics into PHA. PHA is commonly used in medical materials and devices and for making plastic kitchenware, packaging film and other disposable items. It is resistant to hot liquids, greases and oils, but unlike polystyrene, it readily breaks down in soil, water, septic systems and backyard composts.