TECHNOLOGY FOCUS - POLYMERS - Preferred Method: The biomass granulate is prepared with a particle size distribution of 0.1-4 mm, preferably with a dominant fraction of 0.5-2 mm. The PHA is recovered in a system and the method comprises selecting a biomass loading to the system based on a chemometric model calibration such that the recovered PHA has an average molecular weight of at least 350 kDa, preferably greater than 700 kDa. The PHA is extracted in an extraction system and the method comprises selecting a biomass loading to the extraction system based on a bench scale trial to determine the specific scission rate such that the recovered PHA has an average molecular weight of at least 350 kDa, preferably greater than 700 kDa. The PHA is recovered in a reactor and the method comprises selecting a biomass loading to the reactor that achieves a minimum PHA-rich solution concentration of greater than 20 g/l, preferably greater than 40 g/l; The step of pressing the solvent away from the PHA-rich solvent gel produces PHA having a purity of greater than 90%, preferably greater than 98%. The method comprises subjecting the biomass to a pre-extraction process with a solvent that is maintained at a temperature below TL15; blending more than one batch of gelated PHA rich solvent into a combined gelated mass before and/or during mechanically engaging the combined gels to reduce the solvent content; pressing the gel by mechanically engaging the gel with pressures of between 5-30 bar; circulating the solvent through the biomass in the extraction reactor and during the process of circulating the solvent through the biomass in the extraction reactor, dissolving PHA in the biomass into the circulating solvent; servicing more than one batch extraction reactor by a common location of PHA-rich solvent gel; taking the PHA-poor solvent from individual or mixtures of solvents within the groups consisting of aliphatic alcohols, ketones, esters, and/or aromatic hydrocarbons; separating non-dissolved biomass from the PHA-rich solvent and subjecting this biomass to an incineration or pyrolysis process; recovering phosphorus from ash produced in the incineration or pyrolysis process; separating and recovering other chemical products such as lipids and fatty acids as part of the solvent recovery after extraction and separation of the solvent from the PHA-rich solvent gel. heating the biomass and solvent in the reactor to a temperature above a limiting extraction temperature; directing the biomass into the reactor, grinding the biomass to form biomass granules, directing the biomass granules into the reactor and contacting the biomass granules with the solvent; directing the PHA-rich solvent through a heat exchanger disposed in a first section of a conduit and heating the PHA-rich solvent by transferring heat from the heat exchanger to the PHA-rich solvent; directing the PHA-rich solvent through the heat exchanger in a second section of the conduit and cooling the PHA-rich solvent by transferring heat between the heat exchanger in the second section of the conduit and the PHA-rich solvent; mechanically pressing the PHA-rich solvent gel to separate PHA from the PHA-rich solvent gel and form a PHA cake; directing the PHA cake to a dryer and drying the PHA cake; mechanically pressing the PHA-rich solvent gel to expel spent solvent from the PHA-rich solvent gel and purifying the spent solvent by subjecting the spent solvent to an evaporation process and producing a solvent vapor; providing an online monitoring process for monitoring kinetics and progress of PHA extraction by near infrared spectroscopy (NIR). The method further includes condensing the solvent vapor to form a purified solvent. The online monitoring process comprises: measuring temperature compensated changes in the viscosity of the PHA-poor solvent over a selected time period; and monitoring the trends of pressure as a function of temperature in an extraction vessel. Preferred Components: The PHA-in-biomass is thermally stable with a thermal decomposition temperature of greater than 270 degrees C, preferably greater than 280 degrees C. The water content of the dried PHA-containing biomass is less than 10 wt.%, preferably less than 2 wt.%. The content of the dried PHA-rich biomass is at least 35 wt.%, preferably 50 wt.%. The chemical additives including molecular weight stabilizers and/or polymer compounding agents, such as chemical scavengers, antioxidants, nucleating agents, plasticizers and/or reactive polymer modifying agents, and are added to the PHA-poor solvent before or after the formation of a PHA-rich solvent and are blended into the gelated mass before and/or during mechanically engaging the gel to reduce the solvent content. The biomass is separated from the PHA-rich solvent by filtration in an extraction reactor and capturing at least a fraction of the biomass in a trap outside of the extraction reactor.