Improved processes for extracting polyhydroxyalkanoate from a biomass
containing the polyhydroxyalkanoate including the steps of: combining the
biomass containing the polyhydroxyalkanoate with a solvent selected from
lower chain ketones, and mixtures thereof to form a biomass liquor
wherein the biomass liquor comprises less than about 25% water; mixing
the biomass liquor for from about 10 to about 300 minutes at a
temperature in the range of from about 70.degree. C. to about 120.degree.
C.; separating the polyhydroxyalkanoate from the biomass liquor to form a
PHA-enriched liquor, wherein the separating occurs at a temperature of at
least about 40.degree. C.; mixing the PHA-enriched liquor with water to
form precipitated polyhydroxyalkanoate and an impure solvent liquor,
wherein the water is mixed with the PHA-enriched liquor in the ratio of
from at least about 0.4-1 parts of water to one part solvent; and
recovering the precipitated polyhydroxyalkanoate from the impure solvent
liquor. Optional treatment with oxidizing agents or mild surfactant or
mild bleach is used to enhance color and odor.