Polyhydroxyalkanoates production from low-cost sustainable raw materials

The unnerving price of petroleum will push a major change from a petroleum based economy to a natural feedstock based economy. Production of polyhydroxyalkanoates (PHAs) using industrial and agriculture by-products can allow the use of low-cost feedstock to produce materials with specific monomer composition and therefore, with the appropriate physicochemical properties to be used in a broad range of applications. Depending on the monomer composition, PHAs properties can range from thermoplastic to elastomeric materials. Even though PHA has been described as useful polymers due to thier intrinsic biodegradability and biocompatibility, their high price has limited their application significantly. The raw material cost has been known to contribute significantly to the manufacturing cost of PHA. Therefore, much research has been carried out using renewable cheap raw materials to replace the expensive commercial medium, which should reduce the overall production cost. In this review, the production of PHAs using low-cost sustainable raw materials such as molasses, whey, lignocelluloses, fats and oils, glycerol and wastewater are described. Finally, the physicochemical properties of PHAs produced from various carbon sources are discussed.