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.