Methods for purifying polyhydroxy alkanoates
US6340580B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | May 12, 2000 |
| Grant date | Jan 22, 2002 |
| Priority date | — |
| Expiry date | May 12, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G63/06
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A method is provided for isolating and purifying PHA from microbial or plant biomass that contains PHA. The method includes the step of extracting PHA from the biomass using at least one solvent while simultaneously subjecting the biomass to a filtration process to remove cells. In a preferred embodiment of the method, an aqueous slurry of the biomass is directly extracted by diafiltration using an organic solvent. In a preferred diafiltration process, an aqueous slurry of microbial cells comprising PHA is recirculated through a filtration membrane, wherein the membrane has a pore size sufficiently small to reject individual cells or such aggregates of cells as may exist in the slurry. As liquid is progressively removed from the biomass slurry (by flowing out from the filtration membrane), an organic solvent, preferably a water-miscible solvent that also is a solvent for the PHA, is added to the biomass slurry at a rate which approximates the rate of liquid permeation through the filter, thereby maintaining the volume of the biomass slurry. Impurities which are insoluble in water become dissolved in the solvent-water mixture and pass through the filter membrane, and when the organi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.