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US 4,391,766 AGranted
Extraction of poly(.beta.-hydroxybutyric acid)
AssigneeImperial Chemical Industries PLC
InventorsPeter J. Barham, Alan Selwood
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Abstract
.beta.-Hydroxybutyric acid polymers are extracted from micro-organism cells by contact with a solvent, such as 1,2-dichloroethane which is a poor solvent for the polymer once it has been precipitated. The solution obtained by extraction is caused to gel and then solvent is expelled by subjecting the gel to a deformation process. Expelled solvent is recovered for extraction of polymer from a further quantity of cells.
Claims10
A process for the separation of a polymer containing at least 50 mole % of .beta.-hydroxybutyric acid residues in the polymer chain from micro-organism cells comprising
- (a) extracting the polymer from the cells by contacting the polymer-containing cells with a solvent in which the polymer is soluble at the extraction temperature but in which extracted polymer, which has been freshly precipitated and not heated to above 40.degree. C., is not soluble at temperatures below 25.degree. C.,
- (b) separating the solution of the polymer in said solvent from the micro-organism cell residue,
- (c) causing said solution to gel,
- (d) subjecting said gel to a non-random deformation process whereby the bulk of the solvent is expelled from said gel, and
- (e) using at least the bulk of said expelled solvent for extraction of polymer from a further quantity of the polymer-containing cells.
2 more elements
Dependencies are inferred from the claim text.