Method of separating poly-3-hydroxyalkanoic acid

1. A method of producing a poly-3-hydroxyalkanoic acid, which comprises carrying out a physical disruption treatment of a suspension of poly-3-hydroxyalkanoic acid-containing microbial cells with adding an alkali thereto either continuously or intermittently and, thereafter, separating the poly-3-hydroxyalkanoic acid.

2. The method according to claim 1 ,

wherein said addition of an alkali is carried out with controlling the pH of the suspension.

3. The method according to claim 2 ,

wherein the pH of the suspension is controlled between 9 and 13.5.

4. The method according to claim 1 ,

wherein said physical disruption treatment is carried out under stirring of said suspension.

5. The method according to claim 1 ,

wherein said physical disruption treatment is carried out at the temperature not less than 20° C. and below 40° C.

6. The method according to claim 1 ,

wherein the poly-3-hydroxyalkanoic acid is a copolymer comprising of D-3-hydroxyhexanoate (3HH) and one or more other 3-hydroxyalkanoic acids.

7. The method according to claim 6 ,

wherein the poly-3-hydroxyalkanoic acid is a binary copolymer comprising of D-3-hydroxybutyrate (3HB) and D-3-hydroxyhexanoate (3HH) or a ternary copolymer comprising of D-3-hydroxybutyrate (3HB), D-3-hydroxyvalerate (3HV), and D-3-hydroxyhexanoate (3HH).

8. The method according to claim 1 ,

wherein the poly-3-hydroxyalkanoic acid-containing microbial cells are cells of Aeromonas caviae.

9. The method according to claim 1 ,

wherein the poly-3-hydroxyalkanoic acid-containing microbial cells are cells of a strain of microorganism transformed by a poly-3-hydroxyalkanoic acid synthase group gene derived from Aeromonas caviae.