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A process for recovering polyhydroxyalkanoates (PHAs) from cellular biomass of bacteria, said biomass being obtained by fermentation and in the form of a cellular biomass slurry in aqueous suspension, comprising the steps of: submitting the slurry to operations of injection of PHA solvent, agitation

A process for recovering polyhydroxyalkanoates (PHAs) from cellular biomass of bacteria, said biomass being obtained by fermentation and in the form of a cellular biomass slurry in aqueous suspension, comprising the steps of: submitting the slurry to operations of injection of PHA solvent, agitation and heating, in order to form a suspension comprising PHA solvent with the dissolved PHA, water and insoluble residues; recuperating the solvent enriched with PHA; rapidly cooling the solution of PHA solvent to precipitate the dissolved PHA; micro-filtrating the suspension of PHA precipitated in the solvent, in order to separate a paste concentrated with precipitated PHA; washing with water, heating and agitating the concentrated PHA paste, to promote evaporation of the solvent and to obtain a suspension containing PHA granules; agitating and shearing the PHA granules and depleting the residual solvent; and separating the purified PHA particles from the suspension.

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1. A process for recovering polyhydroxyalkanoates (PHAs) from a concentrated cellular biomass slurry of bacteria in an aqueous suspension obtained by a flocculation and concentration method comprising: providing a cellular biomass in suspension in a fermented culture medium,diluting the cellular bio

1. A process for recovering polyhydroxyalkanoates (PHAs) from a concentrated cellular biomass slurry of bacteria in an aqueous suspension obtained by a flocculation and concentration method comprising: providing a cellular biomass in suspension in a fermented culture medium,diluting the cellular biomass in water to form a fermented material to water ratio of up to about 1-3.0:1,acidifying the diluted cellular biomass to between pH 1.5 to about 5.5,adding an alkalizing agent to bring the pH of the biomass to between pH 7 and pH 12.0, andadding a flocculating agent to the alkalized solution to obtain flocculated biomass, the process comprising the steps of: (i) injecting PHA solvent into the concentrated cellular biomass slurry while vigorously agitating the slurry;(ii) heating the slurry in the interior of a reactor to dissolve the PHA contained in the cellular biomass and form a suspension;(iii) separating the solvent, enriched with the dissolved PHA, from the suspension;(iv) rapidly cooling the PHA solvent solution enriched with PHA to a temperature which is sufficient to substantially precipitate all the dissolved PHA;(v) cold micro filtering the solvent solution at a temperature sufficient to precipitate the dissolved PHA;(vi) separating a concentrated paste of precipitated PHA from the micro-filtered solution;(vii) washing the paste concentrated with PHA with water, while heating and agitating the paste, to promote sufficient evaporation of solvent to form a suspension containing brittle PHA granules of high porosity;(viii) agitating the washed and heated PHA granules, while injecting water vapor into the suspension containing the remaining solvent and water, wherein the recovery rate of PHA particles is 90% or greater; and(ix) separating the purified PHA particles from the suspension wherein the cellular biomass is a biomass derived from any microorganism or plant, which can produce PHA naturally or by genetic modification. 2. The process as set forth in claim 1, wherein the PHA solvent used is selected from the group of solvents consisting of: butyl acetate, isobutyl acetate, amyl acetate, isoamyl acetate, isobutyl alcohol, 1-butanol, 1-pentanol (amyl alcohol), 2-methyl-1-butanol, 3-methyl-1-butanol, (isoamyl alcohol), 3-pentanol, 1-hexanol, cyclohexanol, propyl propionate, butyl propionate, isobutyl proprionate, ethyl butyrate, isobutyl isobutyrate, and mixtures of these solvents. 3. The process as set forth in claim 2, wherein the solvent used is isoamyl alcohol, or isomeric mixtures of isoamyl alcohol. 4. The process as set forth in claim 3, wherein the isoamyl alcohol is obtained by fractionizing fusel oil as a by product of the ethanol fermentation, the fusel oil being primordially composed by isoamyl alcohol and isomers thereof, besides impurities, such as: ethanol, n-propanol, isobutanol, n-butanol, and water. 5. The process as set forth in claim 4, wherein the PHA is selected from the group consisting of poly-3-hydroxybutyrate (PHB), poly(hydroxybutyrate-co-hydroxyvalerate) PHBV, and mixtures of these polymers and copolymers. 6. The process as set forth in claim 5, wherein the PHA is produced by bacterial fermentation, using microorganisms which are able to biosynthesize PHA using, as main raw material, sugars extracted from the sugarcane, and in that the main energetic source used to generate the thermal energy and the electric energy required by the process is the sugarcane bagasse. 7. The process as set forth in claim 1, wherein the PHA is selected from the group consisting of poly-3-hydroxybutyrate (PHB), poly(hydroxybutyrate-co-hydroxyvalerate) PHBV, and mixtures of these polymers and copolymers. 8. The process as set forth in claim 1, wherein the bacterial cellular biomass obtained through fermentation and to be processed is previously thermally inactivated. 9. The process as set forth in claim 1, wherein the step of injecting solvent into the concentrated cellular biomass slurry comprises operations of injecting liquid PHA solvent and PHA solvent in the form of vapor, in order to provoke the heating of the cellular biomass to a temperature between about 90° C. and the boiling temperature of the solvent at a substantially atmospheric pressure, and to form: a liquid phase comprising PHA solvent enriched with PHA and water remaining from the cellular biomass slurry; a solid phase defined by the insoluble residues of the residual cellular biomass; and a vapor phase containing vapors of water and of the PHA solvent. 10. The process as set forth in claim 9, wherein it comprises the additional step of extracting the vapor phase from the interior of the reactor. 11. The process as set forth in claim 10, wherein the PHA paste is washed with a water stream coming from the condensation of the vapor phase extracted from the reactor during the step of cellular rupture and PHA dissolution. 12. The process as set forth in claim 1, wherein the acidification of the diluted cellular biomass is obtained by adding an acid defined by at least one of the sulfuric and phosphoric acids. 13. The process as set forth in claim 1, wherein the alkalizing agent comprises calcium hydroxide. 14. The process as set forth in claim 1, wherein the acidification is carried out in order to obtain a pH from about 2.0 to about 3.0. 15. The process as set forth in claim 1, wherein the flocculated biomass is concentrated by at least one of the operations of decantation and centrifugation. 16. The process as set forth in claim 1, wherein the cellular biomass slurry is subjected to washing with water and concentrated to a concentration of the range of 18%-45% of dry cellular biomass. 17. The process as set forth in claim 16, wherein the step of washing and concentrating the cellular biomass slurry is achieved by simultaneously submitting the latter to a flow of water and to the effects of centrifugal force. 18. The process as set forth in claim 1, wherein the PHA solvent which is injected into the cellular biomass slurry is heated. 19. The process as set forth in claim 1, wherein the step of separating the PHA solvent enriched with PHA dissolved therein from the suspension formed inside the reactor comprises at least one of the operations of membrane micro-filtration and of filtration in precoat filters. 20. The process as set forth in claim 1, wherein the step of separating the PHA solvent enriched with PHA dissolved therein from the suspension formed inside the reactor comprises a step of subjecting said suspension to a separation by the effect of centrifugal force of low intensity. 21. The process as set forth in claim 20, wherein the centrifugal force of low intensity, which is used in the step of separating, from the PHA solution enriched with PHA dissolved therein, insoluble residues of the remaining biomass which are contained in the suspension formed inside the reactor, is obtained by means of hydro cyclones, producing a suspension with low concentration of said residues and another suspension concentrated with said residues. 22. The process as set forth in claim 21, wherein the suspension of low concentration of biomass insoluble residues which leaves the hydro cyclones is rapidly submitted to an additional separation step for completely removing the residues before being submitted to the cooling step. 23. The process as set forth in claim 22, wherein the additional separation step is effected by membrane micro-filtration, in order to produce a solution of PHA dissolved in the PHA solvent, free of insoluble residues, and a suspension concentrated in biomass insoluble residues and containing a fraction of PHA dissolved in the PHA solvent, water, ashes, and color compounds dissolved in the PHA solvent. 24. The process as set forth in claim 23, wherein the suspension concentrated in insoluble residues of cellular biomass is subjected to a filtration step, in order to produce a meal containing the biomass insoluble residues and a filtrated solution of PHA dissolved in the solvent, free of insoluble residues and which will be rapidly submitted to the cooling step. 25. The process as set forth in claim 23, wherein the solution of PHA dissolved in the PHA solvent and free of insoluble residues represents about 60-90% by weight of the suspension in micro-filtration, the suspension concentrated in residues of cellular biomass representing about 10-50% by weight of said suspension in micro-filtration. 26. The process as set forth in claim 21, wherein the suspension concentrated with biomass insoluble residues which leaves the hydro cyclones is submitted to a filtration step for separating the biomass insoluble residues before being submitted to the cooling step. 27. The process as set forth in claim 1, wherein the step of cold micro-filtrating the suspension of PHA precipitated in the PHA solvent is carried out in order to produce a PHA paste with a concentration of PHA from about 3.5% to 8.0% w/w. 28. The process as set forth in claim 1, wherein it further comprises the final step of drying the PHA particles separated from the aqueous medium from which the solvent is depleted. 29. The process as set forth in claim 1, wherein the water and PHA solvent vapors, which are generated in the several stages of the process, are condensed and separated in two liquid phases: one solvent-rich liquid phase which returns to the process in the PHA extraction and recovery step; and another solvent-poor liquid phase, which is recirculated in the process to allow recovering the PHA solvent contained therein. 30. The process as set forth in claim 1, wherein the PHA granules obtained in step (vii), after drying, have a particle average size in the range from 40 to 400 ppm and preferably in the range from 100 to 200 ppm. 31. A process for recovering polyhydroxyalkanoates (PHAs) from a cellular biomass of bacteria, said biomass being obtained by fermentation and by using a flocculating agent, in the form of a cellular biomass slurry in aqueous suspension, and with a dry cellular content not inferior to about 18% by weight, characterized in that it comprises the steps of: i) submitting the concentrated cellular biomass slurry to concomitant operations of injection of solvent, capable to dissolve PHAs, of vigorous agitation and of quick heating in the interior of a reactor, in order to provoke the rupture of the walls of the cellular biomass and the dissolution of the PHA contained in the latter, wherein the steps of heating the fermented cellular biomass, of rupturing the cell walls of said cellular biomass, and of dissolving the PHA contained in the latter are carried out in a total time that is sufficiently short to allow obtaining a PHA with a molecular weight at minimum of about 850,000 Da, from a biomass containing PHA with a molecular weight at minimum of about 1,000,000 Da, and to form a suspension comprising solvent, capable to dissolve PHAs, enriched with dissolved PHA, water remaining from the cellular biomass slurry and insoluble residues of the concentrated cellular biomass;ii) submitting the suspension formed in the reactor to a separation step, for recovering the solvent, enriched with the dissolved PHA, from the insoluble residues of the remaining cellular biomass;iii) cooling the solution of the solvent capable to dissolve PHAs, enriched with PHA, in some seconds, by expansion, through heat exchange with another cooler stream or by means of heat exchangers, to a temperature which is sufficient to substantially precipitate all the dissolved PHA;iv) micro-filtrating at 45° C. or less the PHA suspension precipitated in the solvent, capable to dissolve PHAs, containing water and impurities dissolved therein, in order to separate a concentrated paste of precipitated PHA;v) submitting the paste concentrated with PHA to simultaneous operations of washing with water, heating and agitation, in order to promote the evaporation of a certain amount of solvent which is adequate to obtain a suspension containing PHA granules of high porosity and which are brittle and easily shearable, the remaining solvent, and water;vi) submitting the washed and heated PHA granules to agitation and shearing, so as to rapidly break them, while processing the extraction of the residual solvent by injecting water vapor into the suspension containing the remaining solvent and water, in order to obtain purified PHA particles in the suspension; andvii) separating the purified PHA particles from the suspension. 32. The process of claim 1, wherein the flocculating agent is an anionic polyelectrolyte. 33. The process of claim 31, wherein the flocculating agent is an anionic polyelectrolyte.