Patent ID: 7153928

Claim:
A method for producing a polyhydroxyalkanoate crystal which comprises mixing a solution of a polyhydroxyalkanoate in a good solvent with a poor solvent at 50 to 130° C. to precipitate a polyhydroxyalkanoate, wherein the polyhydroxyalkanoate is a copolymer composed of 3-hydroxyhexanoate and 3-hydroxybutyrate, a mixing temperature of the solution of the polyhydroxyalkanoate in the good solvent with the poor solvent is 85 to 130° C. when a ratio of the 3-hydroxyhexanoate in the polyhydroxyalkanoate is less than 13 mol %, and a mixing temperature of the solution of the polyhydroxyalkanoate in the good solvent with the poor solvent is 50 to 84° C. when a ratio of the 3-hydroxyhexanoate in the polyhydroxyalkanoate is not less than 13 mol %.