 The mechanical properties and biocompatibility of PHA can also be changed by blending, modifying the surface or combining PHA with other polymers, enzymes and inorganic materials, making it possible for a wider range of applications.To produce PHA, a culture of a micro-organism such as "Cupriavidus necator" is placed in a suitable medium and fed appropriate nutrients so that it multiplies rapidly.Once the population has reached a substantial level, the nutrient composition is changed to force the micro-organism to synthesize PHA.