 The simplest and most commonly occurring form of PHA is the fermentative production of poly-beta-hydroxybutyrate (poly-3-hydroxybutyrate, P3HB), which consists of 1000 to 30000 hydroxy fatty acid monomers.In the industrial production of PHA, the polyester is extracted and purified from the bacteria by optimizing the conditions of microbial fermentation of sugar, glucose, or vegetable oil.In the 1980s, Imperial Chemical Industries developed poly(3-hydroxybutyrate-"co"-3-hydroxyvalerate) obtained via fermentation that was named "Biopol".