Single solvent polymer extraction methods

1. A method of isolating a PHA from a biomass containing the PHA, the method comprising:

contacting the biomass with a PHA extraction solvent comprising 2-hexanone to form a first combination comprising a PHA phase and a residual biomass phase;

separating the PHA phase from the residual biomass phase;

introducing the PHA phase into a PHA receiving solvent comprising water, thereby forming a second combination;

maintaining the second combination at a temperature and pressure such that the PHA extraction solvent of the PHA phase and a portion of the PHA receiving solvent are removed from the second combination in the gaseous state as an azeotropic mixture; and

precipitating the PHA from the second combination when the PHA extraction solvent is substantially removed from the second combination.

2. The method of claim 1 , wherein the precipitating comprises forming granules of the PHA.

3. The method of claim 2 , wherein the PHA granules have a bulk density of at least about 0.25 kg/m 3 .

4. The method of claim 1 , wherein the first combination is formed by agitating the biomass and the PHA extraction solvent.

5. The method of claim 4 , wherein the agitating is effected by stirring.

6. A method of isolating a PHA, the method comprising:

combining the PHA, a PHA extraction solvent comprising 2-hexanone, and a PHA receiving solvent comprising water, to form a combination; and

maintaining the combination at a temperature and pressure such that the PHA extraction solvent is substantially removed and a portion of the PHA receiving solvent is removed from the combination in the gaseous state as a minimum boiling azeotropic mixture; and

precipitating the PHA from the combination as PHA granules.

7. The method of claim 6 , wherein the PHA granules have a bulk density of at least about 0.25 kg/m 3 .

8. The method of claim 6 , wherein the precipitating the PHA comprises reducing the temperature of the combination after substantially removing the PHA extraction solvent and removing at least a part of the PHA receiving solvent as the minimum boiling azeotropic mixture.

9. The method of claim 6 , wherein the combining comprises combining the PHA and the PHA extraction solvent to form a first combination; and combining the first combination with the PHA receiving solvent to form the combination.