| abstract |
Methods are provided for producing biodegradable polyhydroxyalkanoates (PHAs) with desired geometry, molecular mass, mechanical and/or physical-chemical properties from glycerol, an inexpensive carbon source and byproduct of the biodiesel industry. Microorganisms capable of converting carbon to PHA can be used to convert biodiesel-glycerol to poly-3-hydroxybutyrate (PHB) or other monomer or copolymer PHAs via fermentation. The microorganisms are cultured in a medium comprising glycerol as a primary carbon source and one or more low molecular mass organic acids as a secondary carbon source. Biomass can be harvested from the culture medium and crude PHA extracted and purified, thereby recovering purified PHA with the desired property. After PHA isolation, a nucleating agent can be added to improve certain physical-chemical properties of the PHA, e.g., crystallization temperature, to enhance performance of the PHA during injection molding. |