a method of separating a polymer from a biomass containing the polymer , includes contacting the biomass with a solvent system , the solvent system including a solvent for the polymer and a precipitant for the polymer , to provide a residual biomass and a solution that includes the polymer , the solvent for the polymer and the precipitant for the polymer ; and applying a centrifugal force to the solution and residual biomass to separate at least some of the solution from the residual biomass ; where , the polymer is a polyhydroxyalkanoate ; the precipitant comprises at least one alkane ; the solvent for the polymer is selected from the group consisting of ketones , esters and alcohols and combinations thereof ; and the biomass comprises a slurry of the biomass and water .