Microbial Degradation of Poly(3-Hydroxybutyrate-co-4-Hydroxybutyrate) in Soil

The microbial degradation of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3/4HB) copolymers with different 4HB molar fraction were investigated in soil for 60?days. In the degradation process, changes in weight loss and molecular weight were periodically measured to determine the biodegradability; the surface morphology also was observed using scanning electron microscopy and polarizing optical microscopy. The results showed that the rate of degradation of P3/4HB depends strongly on its crystallinity and surface morphology. Enzymatic degradation, which proceeded via surface erosion mechanisms, was observed mainly during the degradation period in soil. The amorphous interspherulitic regions and crystal center were prone to degrade.