Isolation and purification of bacterial poly(3-hydroxyalkanoates)

The isolation and the purification of bacterial polyhydroxyalkanoates are the key step of the process profitability in the fermentation system. That is why many scientists have studied this field for the production of this biodegradable polymer. The ideal method should lead to a high purity and recovery level at a low production cost. This paper reviews four isolation methods, i.e. solvent extraction of halosolvent and nonhalosolvent, digestion of non-polyhydroxyalkanoate cell material involving surfactants, sodium hypochlorite or enzyme, mechanical cell disruption methods like using bead mills and high pressure homogenization, and new methods like spontaneous liberation of poly(3-hydroxybutyrate), dissolved air flotation, air classification, or by using supercritical CO2. The pretreatment of cell disruption and the purification methods and analytical methods of polyhydroxyalkanoates are also presented.