Biofuel Production, Characterization and Degradation of 3-hydroxybutyate Methyl Ester from Polyhydroxybutyrate

Abstract

Poly(3-hydroxybutyrate) [P(3HB)], isolated from Bacillus licheniformis M2-12, were utilized as biofuel substrate. P(3HB) was esterified by acid- and alkali-catalysis to become 3-hydroxybutyrate methyl ester (3HBME). High 3HBME recovery percentage (68%) and purity (>95%) were obtained from acid catalytic processes. Afterward, 3HBME was further characterized for basic physical, chemical and fuel related properties. According to 3HBME properties such as density, flash point, boiling point and freezing point, 3HBME showed the possible ability to be utilized as a novel biofuel or a fuel additive. In addition, the fuel properties were also compared with ethanol, gasoline, diesel and biodiesel. The degradation of 3HBME was investigated under different storage conditions. Only 5% degradation was found when 3HBME was stored under 4°C. However, 3HBME degradation increased (30-90%) when the storage temperature increased (30-40°C). The highest rate of degradation (90%) was observed in samples stored under 40°C together with air exposure and water.