When plant oil is fermented by certain bacteria, the organisms convert the oil into polyhydroxyalkanoates (PHAs), which accumulate as granules inside their cells. These PHAs serve as an internal energy and carbon storage source. Once sufficient PHA has accumulated, the bacterial cells are harvested, and the PHA is extracted and purified to produce a bioplastic resin. This process is conceptually similar to beer production, where sugars are fermented by yeast to produce alcohol, except in this case, the fermentation product is a biodegradable polymer instead of ethanol.