Extraction methods pol? Merely in a single solvent.

A process for isolating PHA from a biomass having one or more PHA contained in other materials associated with the biomass non PHA, said process comprising: wherein (a) contacting the biomass with a solvent extraction PHA to form a mixture; (B) agitating the mixture of biomass and PHA extraction solvent to form a first combination including a PHA phase and biomass phase residual; (C) separating the PHA phase phase residual biomass; (D) introducing the phase of PHA in a system containing a receiver PHA solvent, to thereby form a second combination, wherein the extraction solvent PHA is capable of forming an azeotrope of minimum boiling solvent receptor PHA; (E) maintaining the system at a temperature and pressure which the PHA extraction solvent phase PHA solvent and a portion of PHA receptor combination in the gaseous state as an azeotropic mixture are removed; and (f) isolating the PHA precipitated in the second combination when the solvent extraction of PHA is substantially removed from the combination, the extraction solvent of PHA is selected from the group consisting of ketones, esters, alcohols and alkanes, the receiver solvent PHA is water and solvent extraction PHA has a melting point higher than the boiling solvent PHA receptor.