Production of PHA using petroleum by-products
By employing petroleum-derived carbon sources in fermentation processes with bacteria, PHA production is achieved efficiently and sustainably, addressing the limitations of conventional methods and enabling the incorporation of aromatic compounds into the polymer.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- MEREDIAN INC
- Filing Date
- 2024-06-24
- Publication Date
- 2026-06-30
AI Technical Summary
Existing methods for producing polyhydroxyalkanoate (PHA) rely on agricultural or food-based carbon sources, which are not always economically viable or environmentally friendly, necessitating the exploration of alternative carbon sources.
Utilizing petroleum-derived carbon sources, such as petroleum fractions and polycyclic aromatic compounds, to produce PHA through fermentation with specific bacterial strains, followed by separation of the polymer from the biomass.
Surprisingly, petroleum-derived carbon sources can be effectively utilized to produce PHA, offering a low-cost and environmentally friendly alternative to conventional carbon sources, with the ability to incorporate aromatic moieties into the polymer structure.
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Figure 2026521641000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to biodegradable polymers. More specifically, the present disclosure relates to a method for producing polyhydroxyalkanoate, a biodegradable polymer, using a petroleum-derived carbon source as a raw material.
Background Art
[0002] Polyhydroxyalkanoate (PHA) is a class of biopolymers with increasing commercial interest and is also a biodegradable and / or compostable polymer. Polyhydroxyalkanoate is most commonly produced by bioconversion, during which a carbon source (i.e., a food source) is converted by bacteria or other microorganisms into the desired polyhydroxyalkanoate. The carbon sources used in this bioconversion typically originate from vegetable oils, hemicellulose, animal fats, sugars, and / or residues from the distillation of vegetable oils.
[0003] Although these carbon sources have been sufficient thus far, as commercial interest in polyhydroxyalkanoate has grown over time, it is desirable to provide alternative carbon sources that can be used in the production of polyhydroxyalkanoate.
Summary of the Invention
Problems to be Solved by the Invention
[0004] Therefore, it is desirable to produce polyhydroxyalkanoate while utilizing a novel carbon source that is inherently of relatively low commercial value and / or is inherently considered dangerous or not environmentally friendly. For example, if petroleum by-products that are otherwise undesirable or of low commercial value could be utilized in the production of polyhydroxyalkanoate, that would be considered desirable.
Means for Solving the Problems
[0005] (Summary of the Invention)
[0006] The above and other needs are met by the method for producing poly(hydroxyalkanoate) using petroleum by-products as a carbon source, as described herein.
[0007] In a first embodiment, the Disclosure provides a method for producing poly(hydroxyalkanoate). In one embodiment, the method comprises a first step of mixing biomass containing bacteria with a petroleum-derived carbon source. The method also comprises a step of fermenting the biomass and carbon source at a temperature of about 25°C to about 35°C for a period of at least 24 hours so that the bacteria in the biomass consume at least a portion of the carbon source and synthesize at least one poly(hydroxyalkanoate). The method further comprises a step of separating at least one poly(hydroxyalkanoate) from the biomass.
[0008] According to this disclosure, a petroleum-derived carbon source consists of (1) a mixture of petroleum fractions, wherein at least 90 weight percent of the petroleum fractions have a boiling point of 400°C or higher, as determined by ASTM D7169, or (2) at least 5 weight percent of at least one polycyclic aromatic compound. For example, in some examples, a petroleum-derived carbon source may be made from certain grades of mineral oil, paraffin, pyrolysis oil, and mixtures thereof. A petroleum-derived carbon source may also be made from polycyclic aromatic compounds such as naphthalene and / or anthracene.
[0009] In a particular preferred embodiment, the petroleum-derived carbon source is composed of a mixture of petroleum fractions, where at least 50 weight percent of the petroleum fractions of the carbon source have a boiling point of 470°C or higher, as determined by ASTM D7169.
[0010] In a particular embodiment, the biomass preferably comprises bacteria selected from the group consisting of species of the genera Cupriavidus, Pseudomonas, and Escherichia, and mixtures thereof.
[0011] In some examples, the biomass bacteria and carbon source are preferably mixed in a weight ratio of about 50 to 99 parts carbon source to 1 part bacteria.
[0012] According to a particular embodiment, the biomass and carbon source are fermented preferably at a pH of about 5 to about 9, more preferably at a pH of about 6 to about 8, and even more preferably at a pH of about 6.5 to about 7.5.
[0013] In certain embodiments, at least one poly(hydroxyalkanoate) preferably has a weight-average molecular weight of at least 1,000 daltons as determined by ASTM 5296-19. More preferably, at least one poly(hydroxyalkanoate) has a weight-average molecular weight of about 1,000 to about 3,000,000 daltons as determined by ASTM 5296-19. Even more preferably, at least one poly(hydroxyalkanoate) has a weight-average molecular weight of about 50,000 to about 500,000 daltons as determined by ASTM 5296-19.
[0014] In certain embodiments, at least one poly(hydroxyalkanoate) preferably comprises a homopolymer. For example, at least one poly(hydroxyalkanoate) may comprise poly-3-hydroxybutyrate.
[0015] In other embodiments, at least one poly(hydroxyalkanoate) preferably comprises a poly(hydroxyalkanoate) copolymer. For example, the poly(hydroxyalkanoate) may include poly-3-hydroxybutyrate-co-3-hydroxyhexanoate ("P(3HB-co-3HHx)").
[0016] According to some embodiments, the poly(hydroxyalkanoate) copolymer preferably comprises at least 87 mole percent of monomer repeating units of hydroxybutyrate (such as 3-hydroxybutyrate or 4-hydroxybutyrate) and about 2 to about 13 mole percent of monomer residues of a second hydroxyalkanoate having 5 to 12 carbon atoms.
[0017] In other embodiments, the poly(hydroxyalkanoate) preferably includes a poly(hydroxyalkanoate) terpolymer. For example, the poly(hydroxyalkanoate) terpolymer may include about 75 to about 99.9 mole percent of monomer repeating units of 3-hydroxybutyrate, about 0.1 to about 25 mole percent of monomer repeating units of 3-hydroxyhexanoate, and about 0.1 to about 25 mole percent of monomer repeating units of a third 3-hydroxyalkanoate having 5 to 12 carbon atoms.
[0018] In some examples, the carbon source preferably consists of at least 5 weight percent of at least one polycyclic aromatic compound.
[0019] In a particular embodiment, at least one poly(hydroxyalkanoate) synthesized from one polycyclic aromatic compound comprises a polymer skeleton having at least one aromatic or polycyclic aromatic moiety incorporated into the polymer skeleton. More preferably, at least one poly(hydroxyalkanoate) comprises a polymer skeleton having at least one anthracene moiety incorporated into the polymer skeleton.
[0020] Further advantages of the present invention will become apparent upon reference to the detailed description when considered in conjunction with the figures, which are not to scale for the purpose of more clearly showing details, and like reference numerals denote like elements throughout the several views.
Brief Description of the Drawings
[0021] [Figure 1] A graph illustrating the boiling point range distribution for mineral oil for use according to one embodiment of the present disclosure.
[0022] [Figure 2] A graph illustrating the boiling point range distribution for paraffin for use according to one embodiment of the present disclosure.
[0023] [Figure 3] The NMR spectrum of polyhydroxyalkanoate synthesized according to one embodiment of the present disclosure.
Mode for Carrying Out the Invention
[0024] The present disclosure provides a method for producing poly(hydroxyalkanoate) using petroleum by-products as an alternative carbon source. Not all organic materials can be digested by bacteria. Further, even if a carbon source is digestible, not all carbon sources are suitable for the production of polyhydroxyalkanoate. Surprisingly, however, according to the present disclosure, certain petroleum-derived carbon sources have been found to be usable for the biological production of poly(hydroxyalkanoate) as a carbon source.
[0025] Generally, the method includes a first step of mixing biomass containing bacteria with a petroleum-derived carbon source. The biomass and the carbon source are then fermented such that the bacteria in the biomass consume at least a portion of the carbon source to synthesize at least one poly(hydroxyalkanoate). The at least one poly(hydroxyalkanoate) is then separated from the biomass.
[0026] Conventionally, the bioconversion of poly(hydroxyalkanoate) polymers has been carried out using carbon sources that are agricultural or food-based products. For example, vegetable oils, hemicellulose, animal oils, sugars, and / or residues derived from the distillation of vegetable oils have generally been used as carbon sources in producing poly(hydroxyalkanoate) polymers.
[0027] However, according to the present disclosure, petroleum-derived carbon sources are used in place of agricultural or food-based carbon sources.
[0028] In particular, petroleum-derived carbon sources are typically (1) a mixture of petroleum fractions, wherein at least 90 weight percent of the petroleum fractions has a boiling point of 400 °C or higher as determined by ASTM D7169, or (2) contain any of at least 5 weight percent of at least one polycyclic aromatic compound.
[0029] For example, in some embodiments, the petroleum-derived carbon source may include certain grades of mineral oil, paraffin, pyrolysis oil, and mixtures thereof, wherein at least 90 weight percent of the fractions of these carbon sources has a boiling point of 400 °C or higher as determined by ASTM D7169.
[0030] For certain embodiments, the petroleum-derived carbon source more preferably includes a mixture of petroleum fractions, wherein at least 50 weight percent of the petroleum fractions of the carbon source has a boiling point of 470 °C or higher as determined by ASTM D7169.
[0031] Petroleum-derived carbon sources may also include polycyclic aromatic compounds. For example, the carbon source may include naphthalene, anthracene, and / or other larger polycyclic aromatic compounds. The petroleum-derived carbon source may, for example, contain at least 5 weight percent of at least one polycyclic aromatic compound. In some embodiments, the petroleum-derived carbon source may contain at least 10 weight percent of at least one polycyclic aromatic compound, at least 20 weight percent of at least one polycyclic aromatic compound, or at least 30 weight percent of at least one polycyclic aromatic compound.
[0032] Surprisingly, according to this disclosure, polyhydroxyalkanoates can be produced using carbon sources that are inherently of relatively low commercial value and / or are inherently considered hazardous or environmentally unfriendly. This is in contrast to the conventional use of agriculturally supplied carbon sources such as vegetable oils, hemicellulose, animal oils, sugars, and / or residues derived from the distillation of vegetable oils.
[0033] This petroleum-derived carbon source is mixed with biomass containing bacteria. Typically, the amount of petroleum-derived carbon source mixed with biomass may vary depending on the specific carbon source used. Typically, the petroleum-derived carbon source and biomass bacteria are mixed in a weight ratio of about 10 to 99 parts carbon source to 1 part bacteria. More preferably, the petroleum-derived carbon source and biomass are mixed in a weight ratio of about 50 to 99 parts carbon source to 1 part bacteria, and even more preferably, in a weight ratio of about 90 to 99 parts carbon source to 1 part bacteria.
[0034] Typically, the carbon source and biomass are mixed in a biofermentation tank or container. The biomass and carbon source are then fermented at a temperature of approximately 25°C to 35°C for at least 24 hours, so that the bacteria in the biomass consume at least a portion of the carbon source and synthesize at least one poly(hydroxyalkanoate).
[0035] More preferably, the biomass and carbon source are then fermented at a temperature of about 25°C to about 35°C for a period of at least 72 hours.
[0036] Generally, biomass and carbon sources are fermented at a pH of approximately 5 to 9, more preferably at a pH of approximately 6 to 8, and even more preferably at a pH of approximately 6.5 to 7.5.
[0037] The biomass contains one or more bacterial species capable of synthesizing poly(hydroxyalkanoate) polymers. Suitable bacterial species that may be included in the biomass include, but are not limited to, bacteria selected from the group consisting of Capriavidus, Pseudomonas, and Escherichia genera, and mixtures thereof.
[0038] During the fermentation process, bacteria in at least a portion of the carbon source biomass synthesize at least one poly(hydroxyalkanoate).
[0039] Typically, at least one synthesized poly(hydroxyalkanoate) has a weight-average molecular weight of at least 1,000 daltons, as determined by ASTM 5296-19. More preferably, at least one poly(hydroxyalkanoate) has a weight-average molecular weight of about 5,000 to about 3,000,000 daltons, as determined by ASTM 5296-19. Even more preferably, at least one poly(hydroxyalkanoate) has a weight-average molecular weight of about 50,000 to about 500,000 daltons, as determined by ASTM 5296-19.
[0040] In various embodiments, the at least one poly(hydroxyalkanoate) synthesized from biomass may be a homopolymer, copolymer, terpolymer, or a mixture thereof.
[0041] In certain embodiments, at least one poly(hydroxyalkanoate) may include a homopolymer. For example, at least one poly(hydroxyalkanoate) may include poly-3-hydroxybutyrate.
[0042] In other embodiments, at least one poly(hydroxyalkanoate) may include a poly(hydroxyalkanoate) copolymer. For example, the poly(hydroxyalkanoate) may include poly-3-hydroxybutyrate-co-3-hydroxyhexanoate ("P(3HB-co-3HHx)").
[0043] According to some embodiments, the poly(hydroxyalkanoate) copolymer preferably comprises at least 87 mole percent of monomer repeating units of hydroxybutyrate (such as 3-hydroxybutyrate or 4-hydroxybutyrate) and about 2 to about 13 mole percent of monomer residues of a second hydroxyalkanoate having 5 to 12 carbon atoms.
[0044] In other embodiments, the poly(hydroxyalkanoate) may include poly(hydroxyalkanoate) terpolymers. For example, the poly(hydroxyalkanoate) terpolymer may contain about 75 to about 99.9 mole percent of monomer repeating units of 3-hydroxybutyrate, about 0.1 to about 25 mole percent of monomer repeating units of 3-hydroxyhexanoate, and about 0.1 to about 25 mole percent of monomer repeating units of a third 3-hydroxyalkanoate having 5 to 12 carbon atoms.
[0045] Furthermore, in some embodiments in which the carbon source includes at least one polycyclic aromatic compound, it has been surprisingly found that at least one poly(hydroxyalkanoate) synthesized from the carbon source can also include a polymer skeleton having at least one aromatic or polycyclic aromatic moiety incorporated into the polymer skeleton. For example, in some examples, at least one poly(hydroxyalkanoate) can include at least one anthracene moiety incorporated into its polymer skeleton.
[0046] Ultimately, according to this disclosure, at least one poly(hydroxyalkanoate) is isolated from the biomass. This isolation may involve one or a series of steps and may include the addition of various enzymes, such as a solubilant for disrupting the bacterial cell wall, an endonuclease for cleaving polynucleotide chains in the bacteria, and / or a peptidase for degrading proteins within the bacteria. Surfactants or detergents may also be used to facilitate the separation of poly(hydroxyalkanoate) from the biomass. [Examples]
[0047] The following non-limiting embodiments illustrate various additional aspects of the present invention. Unless otherwise specified, temperatures are given in Celsius, and percentages are given in weight relative to the dry weight of the formulation.
[0048] In this series of experiments, various carbon source materials were tested to determine whether bacteria could metabolize the carbon sources and synthesize poly(hydroxyalkanoate) using them.
[0049] As the first step, a series of stock solutions were prepared as follows.
[0050] [Table 1]
[0051] [Table 2]
[0052] [Table 3]
[0053] [Table 4]
[0054] [Table 5]
[0055] [Table 6]
[0056] [Table 7]
[0057] [Table 8]
[0058] [Table 9]
[0059] Samples of mineral oil and paraffin used in solutions 3D to 3G were also sent to the Petroleum Testing Laboratory (SGS), and the boiling point range distribution of carbon residues in these compounds was determined according to ASTM D7169. The boiling point range distribution data for mineral oil and paraffin are shown in Figures 1 and 2, respectively.
[0060] Next, a series of shaking flasks containing production media were prepared from the aforementioned stock solution. The pH of each shaking flask was approximately 6.8. The composition of each shaking flask was as follows:
[0061] Table 10
[0062] Table 11
[0063] Table 12
[0064] Table 13
[0065] Table 14
[0066] Table 15
[0067] Table 16
[0068] Table 17
[0069] Table 18
[0070] Table 19
[0071] [Table 20]
[0072] [Table 21]
[0073] [Table 22]
[0074] [Table 23]
[0075] It was previously known that bacteria cannot metabolize either methanol solvent or gum arabic emulsifier to synthesize poly(hydroxyalkanoate). Therefore, the composition of the production medium in each shaking flask may have contained a single carbon source for the synthesis of poly(hydroxyalkanoate).
[0076] Separately, 10 mL of a Capriavidus necator H16 culture was seeded into 60 mL of yeast, wheat peptone, and fructose (YWF) medium in a 250 mL flask with 6 baffles, and incubated at 30°C and 300 rpm for 18 hours to produce bacterial inoculum.
[0077] Next, approximately 9 mL of Capriavidus necatol bacterial inoculum was added to each of the carbon source mixtures in the shaking flask. The shaking flasks were then incubated in a rotary shaker at 300 rpm at 30°C for 72 hours.
[0078] To recover any poly(hydroxyalkanoates) generated during incubation, the cultures from each shaking flask were centrifuged in a 50 mL centrifuge tube at 10,000 Xg for 5 minutes. The supernatant was decanted, and the pellet was resuspended in 50 mL of RO water using a vortex. The pellet was treated with Cocktail A and SeBrite (a protease available from Specialty Enzymes) in a 250 mL flask with six baffles at 37°C and 58°C, respectively. Cocktail A consisted of a mixture of 5.5 mL of Tween 20 surfactant, 5.5 mL of Tween 80 surfactant, 0.66 g of lysozyme, and 44 microliters (μL) of nuclease. Hydrogen peroxide was added, and the pellet was washed twice with RO water and ethanol. After drying (on a benchtop), the recovered material was subjected to analysis to determine (1) the presence or absence of poly(hydroxyalkanoate) using NMR and / or FTIR analysis, and (2) the molar percentage of hydroxyhexanoate monomer in any poly-3-hydroxybutyrate-co-3-hydroxyhexanoate ("P(3HB-co-3HHx)") copolymer using NMR analysis.
[0079] The results are as follows:
[0080] [Table 24]
[0081] The results above confirm the use of poly(hydroxyalkanoates) in the culture broth containing polycyclic aromatics, anthracene, and naphthalene as sole sources of carbon, in the production of polyhydroxyalkanoates, including poly(3-hydroxybutyrate)co-poly(3-hydroxyhexanoate) copolymers. Furthermore, this experiment confirms the use of long petroleum-based hydrocarbon chains, such as those found in mineral oil and paraffin, in the production of polyhydroxyalkanoates, including comonomer poly(3-hydroxybutyrate)co-poly(3-hydroxyhexanoate).
[0082] Finally, polyhydroxyalkanoate samples derived from anthracene and naphthalene shaking flasks were subjected to NMR analysis to verify the presence of anthracene and / or naphthalene within the polyhydroxyalkanoate molecules. The samples from the anthracene shaking flask were found to have incorporated aromatic anthracene rings into the polyhydroxyalkanoate polymer chain. This is illustrated in the NMR spectrum shown in Figure 3, where peaks at approximately 7, 8, and 8.5 indicate the presence of the anthracene moiety in the polyhydroxyalkanoate polymer backbone. There was no indication that naphthalene was similarly incorporated into the polyhydroxyalkanoate polymer chain.
[0083] Embodiment
[0084] This disclosure is further illustrated by the following embodiments.
[0085] Embodiment 1. A method for producing poly(hydroxyalkanoate),
[0086] A process of mixing biomass containing bacteria with a petroleum-derived carbon source.
[0087] A process of fermenting biomass and a carbon source at a temperature of approximately 25°C to approximately 35°C for at least 24 hours, so that the bacteria in the biomass consume at least a portion of the carbon source and synthesize at least one type of poly(hydroxyalkanoate), and
[0088] A process for separating at least one type of poly(hydroxyalkanoate) from biomass. Includes,
[0089] A petroleum-derived carbon source is (1) a mixture of petroleum fractions in which at least 90 weight percent of the petroleum fractions have a boiling point of 400°C or higher as determined by ASTM D7169, or (2) a mixture containing at least 5 weight percent of at least one polycyclic aromatic compound. method.
[0090] Embodiment 2. The method according to Embodiment 1, wherein the petroleum-derived carbon source comprises a mixture of petroleum fractions, and at least 50 weight percent of the petroleum fractions of the carbon source have a boiling point of 470°C or higher, as determined by ASTM D7169.
[0091] Embodiment 3. The method according to Embodiment 1 or 2, wherein the biomass comprises bacteria selected from the group consisting of Capriavidus species, Pseudomonas species, and Escherichia species, and mixtures thereof.
[0092] Embodiment 4. The method according to any of the prior embodiments, wherein the biomass bacteria and carbon source are mixed in a weight ratio of approximately 50 to approximately 99 parts carbon source to 1 part bacteria.
[0093] Embodiment 5. A method according to any of the preceding embodiments, wherein biomass and a carbon source are fermented at a pH of approximately 6.5 to approximately 7.5.
[0094] Embodiment 6. The method according to any of the preceding embodiments, wherein at least one poly(hydroxyalkanoate) has a weight-average molecular weight of at least 1,000 daltons, preferably about 1,000 to about 3,000,000 daltons, and more preferably about 50,000 to about 500,000 daltons, as determined by ASTM 5296-19.
[0095] Embodiment 7. The method according to any of the preceding embodiments, wherein at least one poly(hydroxyalkanoate) comprises a homopolymer.
[0096] Embodiment 8. The method according to any of the preceding embodiments, wherein at least one poly(hydroxyalkanoate) comprises poly-3-hydroxybutyrate.
[0097] Embodiment 9. The method according to any of the preceding embodiments, wherein at least one poly(hydroxyalkanoate) comprises a poly(hydroxyalkanoate) copolymer.
[0098] Embodiment 10. The method according to Embodiment 9, wherein the poly(hydroxyalkanoate) copolymer comprises at least 87 mole percent of monomer repeating units of hydroxybutyrate (such as 3-hydroxybutyrate or 4-hydroxybutyrate) and about 2 to about 13 mole percent of monomer residues of a second hydroxyalkanoate having 5 to 12 carbon atoms.
[0099] Embodiment 11. The method according to any of the prior embodiments, wherein the poly(hydroxyalkanoate) comprises a poly(hydroxyalkanoate) terpolymer.
[0100] Embodiment 12. The method according to Embodiment 11, wherein the poly(hydroxyalkanoate) terpolymer comprises about 75 to about 99.9 mole percent of monomer repeating units of 3-hydroxybutyrate, about 0.1 to about 25 mole percent of monomer repeating units of 3-hydroxyhexanoate, and about 0.1 to about 25 mole percent of monomer repeating units of a third 3-hydroxyalkanoate having 5 to 12 carbon atoms.
[0101] Embodiment 13. The method according to any of the prior embodiments, wherein the carbon source comprises at least one polycyclic aromatic compound.
[0102] Embodiment 14. The method according to Embodiment 13, wherein at least one poly(hydroxyalkanoate) comprises a poly(hydroxyalkanoate) having a polymer skeleton having at least one aromatic or polycyclic aromatic moiety incorporated into the polymer skeleton.
[0103] Embodiment 15. The method according to Embodiment 13, wherein at least one poly(hydroxyalkanoate) comprises a poly(hydroxyalkanoate) having a polymer backbone having at least one anthracene moiety incorporated into the polymer backbone.
[0104] The foregoing descriptions of preferred embodiments relating to this disclosure are presented for illustrative and explanatory purposes only. They are not intended to be exhaustive or to limit this disclosure to the exact form disclosed. Obvious modifications and changes are possible in light of the above teachings. These embodiments have been selected and described as part of an effort to provide best examples of the principles of this disclosure and their practical applications, thereby enabling those skilled in the art to utilize this disclosure with various modifications in various embodiments to suit a particular intended use.
Claims
1. A method for producing poly(hydroxyalkanoate), A process of mixing biomass containing bacteria with a petroleum-derived carbon source. A process of fermenting biomass and a carbon source at a temperature of 25°C to 35°C for at least 24 hours, so that bacteria in the biomass consume at least a portion of the carbon source and synthesize at least one type of poly(hydroxyalkanoate), and A process for separating at least one type of poly(hydroxyalkanoate) from biomass, Includes, A petroleum-derived carbon source is (1) a mixture of petroleum fractions in which at least 90 weight percent of the petroleum fractions have a boiling point of 400°C or higher as determined by ASTM D7169, or (2) a mixture containing at least 5 weight percent of at least one polycyclic aromatic compound. method.
2. The method according to claim 1, wherein the petroleum-derived carbon source comprises a mixture of petroleum fractions, and at least 50 weight percent of the petroleum fractions of the carbon source have a boiling point of 470°C or higher, as determined by ASTM D7169.
3. The method according to claim 1, wherein the biomass comprises bacteria selected from the group consisting of species of the genera Capriavidus, Pseudomonas, and Escherichia, and mixtures thereof.
4. The method according to claim 1, wherein the biomass bacteria and carbon source are mixed in a weight ratio of 50 to 99 parts of carbon source to 1 part of bacteria.
5. The method according to claim 1, wherein the biomass and carbon source are fermented at a pH of 6.5 to 7.
5.
6. The method according to claim 1, wherein at least one poly(hydroxyalkanoate) has a weight-average molecular weight of at least 1,000 daltons as determined by ASTM 5296-19.
7. The method according to claim 1, wherein at least one poly(hydroxyalkanoate) comprises a homopolymer.
8. The method according to claim 1, wherein at least one poly(hydroxyalkanoate) comprises poly-3-hydroxybutyrate.
9. The method according to claim 1, wherein at least one poly(hydroxyalkanoate) comprises a poly(hydroxyalkanoate) copolymer.
10. The method according to claim 9, wherein the poly(hydroxyalkanoate) copolymer comprises at least 87 mole percent of hydroxybutyrate monomer repeating units and 2 to 13 mole percent of a second hydroxyalkanoate monomer residue having 5 to 12 carbon atoms.
11. The method according to claim 1, wherein the poly(hydroxyalkanoate) comprises a poly(hydroxyalkanoate) terpolymer.
12. The method according to claim 11, wherein the poly(hydroxyalkanoate) terpolymer comprises 75 to 99.9 mole percent of monomer repeating units of 3-hydroxybutyrate, 0.1 to 25 mole percent of monomer repeating units of 3-hydroxyhexanoate, and 0.1 to 25 mole percent of monomer repeating units of a third 3-hydroxyalkanoate having 5 to 12 carbon atoms.
13. The method according to claim 1, wherein the carbon source comprises at least one polycyclic aromatic compound.
14. The method according to claim 13, wherein at least one poly(hydroxyalkanoate) comprises a poly(hydroxyalkanoate) having a polymer skeleton having at least one aromatic or polycyclic aromatic moiety incorporated into the polymer skeleton.
15. The method according to claim 13, wherein at least one poly(hydroxyalkanoate) comprises a poly(hydroxyalkanoate) having a polymer skeleton having at least one anthracene moiety incorporated into the polymer skeleton.