Method for producing gamma-butyrolactone from biomass

Abstract

An improved method for producing a high-purity gamma-butyrolactone (GBL) product in high yield from a starting biomass containing poly-4-hydroxybutyrate (P4HB) and water is disclosed. The method comprises the step of recycling a portion of the GBL product to replace water in order to obtain a substantially water-removed biomass slurry that undergoes a conversion process to convert the P4HB into GBL.

Description

Technology Field

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 325,243 filed on March 30, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to an improved process for producing gamma-butyrolactone (GBL) from biomass. Background Technology

[0003] With concerns over depleting petroleum resources, rising energy prices, and environmental issues, the development of energy-efficient biorefining processes to produce bio-based chemicals from renewable and inexpensive carbon sources offers a unique solution to overcome the increasing limitations of petroleum-based chemicals.

[0004] One of the chemicals with a wide range of industrial and pharmaceutical applications that can be manufactured using biopurification processes is gamma-butyrolactone (GBL). Global market demand for GBL is estimated at £850 million annually, which translates to a total annual revenue of $1 billion. GBL is a colorless, mild-odored liquid primarily used as an intermediate in the production of commercially important chemicals such as 1,4-butanediol (BDO), tetrahydrofuran (THF), N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), 2-pyrrolidinone, N-vinylpyrrolidone (NVP), and polyvinylpyrrolidone (PVP). These chemicals are applied as high-performance solvents for electronics, lubricant extraction, magnetic wire coating, engineering resins, pharmaceutical intermediates, cosmetics, hairspray, and high-value polymers. GBL itself has numerous uses, including paint stripping, degreasing agents, viscosity modifiers for polyurethane, dispersants for water-soluble inks, curing agents for urethanes and polyamides, etching agents for metal-coated plastics, rubber additives, and herbicide components.

[0005] Petroleum-based GBL is manufactured by various chemical processes. For example, GBL is synthesized by the dehydration of gamma-hydroxybutyric acid (GHB), the reaction of acetylene with formaldehyde, or the gas-phase hydrogenation of maleate anhydride or succinate anhydride and their esters. The last two methods are known as the Reppe process and the Davy process, respectively. The Reppe process was developed in the 1940s and was historically the first commercial route for the production of 1,4-butanediol. This process begins by reacting acetylene with formaldehyde, undergoes a series of hydrogenation steps to obtain BDO, and finally produces GBL through dehydrogenation. The main disadvantage of this process is that the starting reactants are highly hazardous and generally pose handling and environmental issues for manufacturers. Additionally, acetylene is a relatively expensive starting material.

[0006] The Davy process, developed in the 1990s, utilizes a multi-step process that begins with the reaction of molten maleic anhydride with methanol to produce monomethyl maleate. Next, monomethyl maleate is converted to dimethyl maleate in the presence of an acidic resin catalyst. Through a catalytic gas-phase hydrogenation reaction, dimethyl maleate is converted to dimethyl succinate, which is then finally converted to GBL through a series of additional reactions. The final product is purified to provide high-purity GBL. Numerous patents describe various types of hydrogenation catalysts used for the conversion of maleate anhydride or succinate anhydride to GBL. These include copper chromite (described in U.S. Patent No. 3,065,243), nickel-containing copper chromite (U.S. Patent No. 4,006,165), mixtures of copper, zinc, or aluminum oxide (U.S. Patent No. 5,347,021), and mixtures of reduced copper and aluminum oxide (U.S. Patent No. 6,075,153).

[0007] Despite the vast number of hydrogenation catalysts for GBL production, there are drawbacks that need to be overcome, such as yield, selectivity, ease of product recovery, and cost.

[0008] U.S. Patent No. 9,084,467 discloses a process for producing a bio-based gamma-butyrolactone product, the process comprising: a) combining genetically modified biomass containing poly-4-hydroxybutyrate (P4HB) with a catalyst; and b) heating the biomass containing the catalyst to convert P4HB into a GBL product, wherein the catalyst is sodium carbonate or calcium hydroxide.

[0009] U.S. Patent Application Publication No. 2014-0170714 discloses a process for the production and purification of bio-based GBL, wherein the process comprises: a) combining genetically modified biomass containing poly-4-hydroxybutyrate (P4HB) with a catalyst; b) heating the biomass containing the catalyst to convert P4HB into a GBL product; and c) removing impurities from the GBL product to form pure GBL.

[0010] According to U.S. Patent No. 9,084,467 and U.S. Patent Application Publication No. 2014-0170714, during or after the production (e.g., culture) of P4HB biomass, the biomass is combined with a catalyst under suitable conditions to help convert the P4HB polymer into a high-purity GBL product. The catalyst (in solid or solution form) and the biomass are combined, for example, by mixing, aggregation, centrifugation, or spray drying, or by other suitable methods used to promote the interaction between the biomass and the catalyst to induce an efficient and selective conversion of P4HB to GBL. The biomass is initially dried for a certain period of time, for example, at a temperature of about 100°C to about 150°C, to reduce the moisture content of the biomass. Subsequently, the dried biomass is resuspended in water to proceed with the conversion to obtain GBL before combining with the catalyst. The full contents of U.S. Patent No. 9,084,467 and U.S. Patent Application Publication No. 2014-0170714 are incorporated herein by reference.

[0011] Conventional processes for producing GBL from poly(4-hydroxybutyric acid) (P4HB), such as those described in U.S. Patent No. 9,084,467 and U.S. Patent Application Publication No. 2014-0170714, include a step of spray-drying biomass from a fermentation culture (a water removal step), or a drying step (e.g., using a high-temperature drum dryer (e.g., a high-temperature metal surface at 300°C)), followed by a pyrolysis step, i.e., a step of converting P4HB to GBL through a reaction with a catalyst. Conventional drying processes for biomass are energy-intensive and inefficient. A drying step is required because the biomass containing P4HB must be heated to above 150°C for the conversion of P4HB to GBL. The generated GBL is in a highly unrefined state, containing significant amounts of N-methylpyrrolidone (NMP) and various other organic compounds (furfurol and amines) that can impart color and odor to the product, and therefore requires post-processing and distillation that necessitate high reflux rates and a large number of trays within the column. The conversion process itself may require high surface temperatures, and some difficult solids treatment issues may arise. The problem to be solved

[0012] Therefore, it is necessary to develop a new GBL manufacturing process using sustainable starting materials that not only improves product yield, purity, and cost but also has a more positive impact on the environment. means of solving the problem

[0013] One aspect of the present disclosure relates to a process for producing a high-purity, high-yield, bio-based gamma-butyrolactone (GBL) product from a bio-based renewable carbon source, comprising the steps of removing water from a bio-based renewable carbon source (starting biomass) and introducing a recycled stream of GBL to replace at least a portion of the removed water. In one embodiment, a process for producing a gamma-butyrolactone (GBL) product from a starting biomass containing poly-4-hydroxybutyrate (P4HB) comprises the steps of removing water from the starting biomass by replacing the water with a recycled stream of steam or liquid GBL to obtain a substantially water-removed biomass in the form of a suspension or solution containing P4HB dissolved or suspended in the GBL, and combining the substantially water-removed biomass thus obtained, containing P4HB and GBL, with a catalyst and heating the P4HB-containing biomass containing the catalyst to convert the P4HB into a gamma-butyrolactone (GBL) product. Thus, the steam or liquid GBL introduced into the biomass, in particular the steam or liquid recycled GBL, acts as a solvent for P4HB (P4HB extracted from host cells within the biomass). The terms “substantially water-removed” or “substantially water-free” as used throughout this disclosure are intended to indicate that the biomass introduced into the conversion reaction (i.e., the step of combining with a catalyst) contains water in an amount of about 5 wt% or less, about 4.5 wt% or less, about 4 wt% or less, about 3.5 wt% or less, about 3 wt% or less, about 2.5 wt% or less, about 2 wt% or less, about 2 wt% or less, about 1.5 wt% or less, or about 1 wt% or less, based on the weight of the biomass combined with the conversion reaction catalyst. In some embodiments, the biomass combined with the conversion reaction catalyst does not contain any added water.In a non-limiting embodiment, the process may be carried out using a multiple-effect evaporator.

[0014] A multi-effect evaporator is a device that evaporates water by efficiently using heat from steam. Water boils in a series of vessels (columns), each vessel maintained at a pressure lower than that of the previous vessel. Since the boiling point of water decreases as the pressure decreases, the steam boiling in one vessel can be used to heat the next vessel, and thus an external heat source is required only for the first vessel (at the highest pressure). Theoretically, evaporators can be constructed with any number of stages, but evaporators with four or more stages are rarely practical except for systems intended for liquid as a product, such as chemical recovery systems where up to seven stages are used.

[0015] The process of the present disclosure obtains a suspension or solution of biomass to be combined with a conversion reaction catalyst by removing and replacing the water contained in the starting biomass with a liquid or vapor GBL acting as a solvent for P4HB at least once, at least twice, or at least three times. The suspension or solution of the biomass contains P4HB (extracted from the host cells of the biomass) dissolved or suspended in the GBL that replaced the water contained in the starting biomass. The starting biomass from the fermentation culture generally contains about 10-30% biomass (solid), and the remainder is water. The entire process from the initial loading of the starting biomass to the completion of the conversion reaction is a fluid process that does not use additional solvents such as added water, and does not include a drying process (since the GBL functions / acts as a solvent for P4HB). By using liquid or vapor GBL that is recycled back into biomass as a solvent, the purity and yield of the GBL obtained as a conversion product are improved, and the energy efficiency of the process is enhanced.

[0016] Introducing a recycled steam or liquid stream of GBL into the biomass to obtain a substantially water-removed biomass suspension or solution combined with a catalyst for the conversion of P4HB to GBL can help lower the conversion reaction temperature and reduce the amount of high-boiling point, foul-smelling impurities. This method significantly improves heat transfer and reduces the amount of energy used in the process by at least 50%.

[0017] The content of P4HB in the starting biomass exceeds 10% by weight based on the weight of the total starting biomass. The starting biomass or bio-based renewable starting material may be genetically modified biomass as described in US 9,084,467 B2, the entire contents of which are incorporated herein by reference. The advantage of this bioprocess is that a renewable carbon source is used as a feedstock, and genetically modified microorganisms produce P4HB in very high yields without toxic effects on host cells (which may limit process efficiency), and when combined with a catalyst and heated, bio-based GBL can be produced in good yields with good purity.

[0018] In some embodiments, the steam or liquid GBL introduced to replace the water contained in the starting biomass is a fully recycled stream (liquid or steam) GBL produced from P4HB by a conversion process. In some other embodiments, a portion of the steam or liquid GBL introduced to replace the water contained in the starting biomass is added to the GBL, and the remainder of the steam or liquid GBL is used as a recycled stream. The added GBL may be bio-based GBL or petroleum-based GBL. The process according to the present disclosure may be a continuous process, and the added GBL may be introduced only at the beginning of the process until the amount of recycled GBL can replace substantially all the water in the biomass, and all of the GBL introduced into the biomass may be recycled GBL. The term “added GBL” is intended to refer to GBL introduced into the biomass from a source other than recycled GBL. The present disclosure relates to a bio-based gamma-butyrolactone (GBL) product produced by the process described herein. In a specific embodiment, the amount of GBL in the produced conversion product (prior to production-post-purification, e.g., distillation) is 85 wt%, or greater than 85 wt%, or greater than 90 wt%, or greater than 91 wt%, or greater than 92 wt%, or greater than 93 wt%, or greater than 94 wt%, or greater than 95 wt%. In a further embodiment, the starting biomass comprising poly-4-hydroxybutyrate produced from a renewable source suitable as a feedstock for the production of gamma-butyrolactone products contains greater than 10%, greater than 20%, greater than 30%, greater than 40%, or greater than 50% of poly-4-hydroxybutyrate based on the weight of the said biomass.

[0019] Specifically, the present disclosure relates to the following items.

[0020] Item 1. A method for producing a gamma-butyrolactone (GBL) product from a starting biomass comprising water and cells containing poly-4-hydroxybutyrate (P4HB), wherein the method comprises:

[0021] (a) A step of introducing the above-mentioned starting biomass into an evaporator,

[0022] (b) introducing liquid or vapor GBL as a solvent with a weight equal to or less than the weight of the removed water into the evaporator to obtain a biomass suspension or solution comprising P4HB dissolved or suspended in the GBL, in which water is substantially removed.

[0023] (c) combining the substantially water-removed biomass suspension or solution with a conversion catalyst, and heating the resulting mixture to convert the P4HB into GBL, and

[0024] (d) includes the step of collecting the above GBL,

[0025] Here, the liquid or vapor GBL introduced in step (b) is recycled GBL, which is part of the GBL collected in step (d), and is recycled back to the evaporator and mixed with the biomass as a solvent, and

[0026] The above method is a method that does not include a drying step.

[0027] Item 2. Item 1, wherein (e) a mixing, stirring, vortexing, or strong stirring step further comprising to facilitate the extraction of P4HB from host cells into GBL.

[0028] Item 3. The method of Item 1, further comprising, prior to step (c), (f) a step of removing solids from a biomass suspension or solution from which water has been substantially removed by filtration, sedimentation, or centrifugation.

[0029] Item 4. Method of Item 1, in which water is not added in steps (a), (b) and (c).

[0030] Item 5. The method of Item 1, wherein the evaporator comprises a plurality of series evaporators fluidly connected to one another, and the recycled liquid GBL is introduced into one or more of the evaporators.

[0031] Item 6. The method of Item 1, wherein the evaporator comprises a first evaporator, a second evaporator and a third evaporator, said evaporators fluidly communicating with one another in series in the said order, and a recycled GBL is introduced into said second evaporator and / or said third evaporator.

[0032] Item 7. In Item 1, step (a) is performed at a temperature of about 60°C to 100°C under vacuum or atmospheric pressure, a method.

[0033] Item 8. A method according to Item 6, wherein about 20–50% of the water contained in the starting biomass is removed in a first evaporator, about 20–45% of the water contained in the starting biomass is removed in a second evaporator, and about 5–35% of the water contained in the starting biomass is removed in a third evaporator; wherein recycled GBL is introduced to replace the water removed from the first and second evaporators.

[0034] Item 9. The method of Item 1, wherein the substantially water-removed biomass solution or suspension comprises a water content of about 5 wt% or less, about 4 wt% or less, about 3.5 wt% or less, about 3 wt% or less, about 2.5 wt% or less, about 2 wt% or less, about 1.5 wt% or less, or about 1 wt% or less, based on the weight of the biomass solution or suspension.

[0035] Item 10. In Item 1, step (a) is performed under vacuum at a temperature of about 70°C to 90°C, a method.

[0036] Item 11. In Item 1, step (a) is performed at a time interval of about 5 minutes to about 2 hours.

[0037] Item 12. A method according to Item 1, wherein the GBL collected in step (d) contains less than 5% by weight of by-products.

[0038] Item 13. A method in which the conversion of step (c) of Item 1 is performed in the presence of a catalyst.

[0039] Item 14. The method of Item 13, wherein the catalyst is sodium carbonate or calcium hydroxide.

[0040] Item 15. A method according to Item 1, wherein the yield of the GBL product is about 85% by weight or more, based on 1 gram of GBL in the converted product per gram of poly-4-hydroxybutyrate.

[0041] Item 16. The method of Item 1, wherein the starting biomass is genetically engineered biomass from host cells containing a non-naturally occurring amount of P4HB.

[0042] Item 17. Bio-based gamma-butyrolactone product produced by the method of Item 1.

[0043] Item 18. In Item 17, the gamma-butyrolactone product comprises less than 5% by weight of by-products, a bio-based gamma-butyrolactone product Effects of the invention

[0044] An improved method for producing a high-purity gamma-butyrolactone (GBL) product in high yield from starting biomass containing poly-4-hydroxybutyrate (P4HB) and water is disclosed. The method comprises the step of recycling a portion of the GBL product to replace water in order to obtain a substantially water-removed biomass slurry that undergoes a conversion process to convert P4HB to GBL. Brief explanation of the drawing

[0045] Figure 1 is a schematic diagram of an exemplary process for the production of GBL from P4HB biomass. Figure 2 shows a 30% solution of 300 K Da P4HB in GBL (left) (P4HB is dissolved in GBL) and an extract of P4HB from biomass containing GBL in Rotovap (right). Figure 3 is a photograph of P4HB extracted using GBL and precipitated in water. Figure 4 is a schematic diagram of another exemplary process for the production of GBL from P4HB biomass. Specific details for implementing the invention

[0046] The present disclosure relates to a novel process that introduces a recycled stream of GBL into a reaction step to help lower the reaction temperature and reduce the amount of foul-smelling impurities with high boiling points. The process significantly improves heat transfer and reduces the amount of energy used in the process by at least 50% compared to existing processes that include a biomass drying step.

[0047] The process according to the embodiment eliminates the drying step of biomass (spray drying or drum drying), thereby reducing energy costs by up to 50% compared to existing processes that include the drying step of biomass.

[0048] The process according to the embodiment reduces the maximum temperature through which the biomass undergoes a conversion reaction in which P4HB is converted to GBL by the action of a catalyst under heat treatment, and reduces the amount of side reactions that produce a significant amount of N-containing compounds, such as N-methylpyrrolidone (NMP). NMP is a known carcinogen and is a persistent impurity that is difficult to separate from GBL because the difference in boiling point (BP) is only 2°C. Removing N from the biomass before the conversion reaction can reduce the amount of NMP impurities.

[0049] The process according to the embodiment eliminates the biomass drying step, thereby eliminating the need to handle any solids at the manufacturing plant.

[0050] The process according to the embodiment is significantly cost-effective because the conversion product contains high-yield, high-purity GBL, and subsequent separation or purification steps using, for example, distillation / condensation column(s) to obtain the desired purity and / or yield of the final GBL can be performed with reduced separation capacity. In some embodiments, the resulting GBL product concentrate is >99% GBL without any distillation. This slurry / solution can be fed to a reactor to further decompose the remaining polymer before recovery. The process according to the embodiment is a highly clean process capable of producing 99.9% purity GBL in a single distillation step, while virtually eliminating high-temperature decomposition byproducts of biomass.

[0051] In certain embodiments, genetically modified P4HB biomass from a host organism serves as a renewable source for the conversion of poly-4-hydroxybutyrate (P4HB) to GBL. In some embodiments, the source of the renewable feedstock is selected from glucose, fructose, sucrose, arabinose, maltose, lactose, xylose, fatty acids, vegetable oils, and biomass-derived synthesis gas, or a combination of two or more of these. In certain embodiments, the heating of the substantially water-removed biomass suspension or solution and the catalyst (i.e., the conversion reaction) is carried out at a temperature of about 190°C to about 300°C. In some embodiments, the heating temperature is about 195°C to about 285°C, or about 200°C to about 275°C, or about 200°C to about 260°C, or about 200°C to about 250°C, or about 195°C to about 265°C, or about 200°C to about 260°C, or about 205°C to about 250°C, or about 210°C to about 240°C. In other embodiments, the heating temperature is about 190 to 220°C. In some aspects, the multi-effect evaporation process reduces the moisture content of the biomass to about 15 wt% or less, about 12 wt% or less, about 10 wt% or less, about 9 wt% or less, about 8 wt% or less, about 7 wt% or less, about 6 wt% or less, or about 5 wt% or less. In the described embodiment, heating of the substantially water-removed biomass suspension or solution and catalyst is performed for a time of about 30 seconds to about 5 minutes, or about 1 minute to about 4 minutes, or about 2 minutes to about 3 minutes, or about 5 minutes to about 2 hours, or about 10 minutes to about 90 minutes, or about 20 minutes to about 80 minutes, or about 30 minutes to about 70 minutes, or about 40 minutes to about 60 minutes, or about 45 minutes to about 55 minutes.In a specific embodiment, gamma-butyrolactone contains less than 10%, or less than 9%, or less than 8%, or less than 7%, or less than 6%, or less than 5%, or less than 4%, or less than 3%, or less than 2%, or less than 1% of by-products.

[0052] In a specific embodiment, the catalyst for the conversion reaction is sodium carbonate or calcium hydroxide. The weight percentage of the catalyst is in the range of about 4% to about 50%, or about 8% to about 45%, or about 10% to about 40%, or about 15% to about 35%, or about 20% to about 30%, or about 25% to about 30%, based on the total weight of the mixture of the substantially water-removed biomass suspension or solution and the catalyst. In a specific embodiment, the weight percentage of the catalyst is in the range of about 4% to about 50%, and the heating of the substantially water-removed biomass suspension or solution and the catalyst is carried out at about 300°C, or about 280°C, or about 250°C, or about 240°C, or about 230°C, or about 220°C, or about 210°C, or about 200°C. In some embodiments, the catalyst is 4%, or 5%, or 6%, or 7%, or 8%, or 9%, or 10%, or 11%, or 12%, or 13%, or 14%, or 15% based on the weight of calcium hydroxide, and heating is performed at a temperature of about 300°C, or about 290°C, or about 280°C, or about 270°C, or about 260°C, or about 250°C, or about 240°C, or about 230°C, or about 225°C, or about 220°C, or about 215°C, or about 210°C, or about 205°C, or about 200°C, or about 195°C.

[0053] For the purposes of the present disclosure, P4HB is also defined as comprising a copolymer of 4-hydroxybutyrate and 3-hydroxybutyrate, wherein the percentage (%) of 4-hydroxybutyrate in the copolymer is 80%, or 82%, or 85%, or 88%, or 90%, or 92%, preferably greater than 95% of the monomer in the copolymer.

[0054] In some embodiments, about 0.1 to 30 weight percent of the GBL product from the conversion reaction may be recycled back to the evaporator. In some embodiments, about 0.5 to 30 weight percent of the GBL product, or about 0.5 to 20 weight percent of the GBL product, or about 0.5 to 10 weight percent of the GBL product, or about 1 to 30 weight percent of the GBL product, or about 1 to 20 weight percent of the GBL product, or about 2 to 25 weight percent of the GBL product, or about 2 to 20 weight percent of the GBL product, or about 2 to 15 weight percent of the GBL product, or about 3 to 20 weight percent of the GBL product, or about 3 to 15 weight percent of the GBL product, or about 1 to 10 weight percent of the GBL product, or about 2 to 10 weight percent of the GBL product, is recycled back to the evaporator. Here, if the steam GBL is recycled, the corresponding recycling rate can be converted into the corresponding volume %.

[0055] In some embodiments, the final GBL is further processed for the production of other desired goods and special products, such as 1,4-butanediol (BDO), tetrahydrofuran (THF), N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), 2-pyrrolidinone, N-vinylpyrrolidone (NVP), polyvinylpyrrolidone (PVP), etc.

[0056] As used herein, “biomass” or “starting biomass” is intended to mean any genetically modified biomass from a host (e.g., recombinant bacteria) comprising a non-naturally occurring amount of a polyhydroxyalkanoate polymer, e.g., poly-4-hydroxybutyrate (P4HB), as disclosed in U.S. Patent No. 9,084,467, the contents of which are incorporated herein by reference. The polyhydroxyalkanoate polymer comprises a homopolymer of 4-hydroxybutyrate, a copolymer of other monomers such as 4-hydroxybutyrate and 3-hydroxybutyrate, or a mixture thereof.

[0057] Referring to FIG. 1, an exemplary embodiment of the present disclosure comprises at least a triple-effect evaporator comprising a first evaporator (1), a second evaporator (2), a third evaporator (3), a reaction vessel (4), a distillation column (5), a condenser (6) for collecting water vapor, and a condenser (7) for collecting GBL vapor. The first evaporator (1), the second evaporator (2), and the third evaporator (3) are fluidly connected to each other in series according to the corresponding order. Although FIG. 1 illustrates three evaporators, the present disclosure is not limited thereto.

[0058] A fermentation culture medium (starting biomass) containing 10% to 50% by weight (based on the total weight of the culture medium) of biomass containing P4HB is supplied to a first evaporator (1) and heated to about 60°C to 100°C for a certain period of time under vacuum or atmospheric pressure using a device known in the art to reduce the moisture content. The water vapor is removed into a vessel such as a condenser (6). Based on the total weight of the culture medium, about 20% to 50% by weight, or about 25% to 45%, or about 30% to 40% of water is removed in the first evaporator.

[0059] The liquid with reduced moisture content is transferred to a second evaporator (2), where a recycled GBL stream is added to replace the water removed from the first evaporator. The second evaporator is heated to 60°C to 100°C for a certain period of time under vacuum or atmospheric pressure using a device known in the art to further reduce the moisture content. The water vapor is removed into a vessel such as a condenser (6). Based on the total weight of the culture medium, about 20% to 45% by weight, or about 25% to 40%, or about 30% to 35% of the water is removed in the second evaporator (2). As the GBL content increases toward the third evaporator (3), the temperature and pressure can be adjusted to facilitate the efficient evaporation of the residual water.

[0060] Liquid biomass containing additionally reduced moisture content (i.e., a mixture of biomass, GBL, and residue) is transferred to a third evaporator (3), which is heated for a certain period of time at about 60°C to 100°C under vacuum or atmospheric pressure using a device known in the art to reduce the moisture content. Residual moisture in the culture medium is removed into a vessel such as a condenser (6) to provide a slurry containing biomass essentially containing P4HB (P4HB biomass) and GBL, wherein the biomass is substantially free of moisture. The slurry can be supplied directly to a reaction vessel (4) for combination with a catalyst. The heating temperature of the reaction vessel is generally about 50°C to 130°C, or about 60°C to 120°C, or about 70°C to 115°C, or about 80°C to 110°C, or about 85°C to 105°C, or about 90°C to 100°C, or about 100°C lower than the heating temperature of the conventional process. The reaction vessel may be an LTP (low temperature pyrolysis) unit spray pyrolysis / fluidized bed / or general reaction vessel, etc. Alternatively, for flash pyrolysis, the slurry may be preheated to 300°C and delivered to an LTP spray nozzle. The slurry (unit liquid feed) has a heat transfer rate three times better than conventional dried biomass powder obtained by spray drying or drum drying.

[0061] In another embodiment, the slurry (also referred to as “substantially water-removed biomass suspension or solution” or “biomass suspension or solution”) is optionally stirred, mixed, vortexed, or vigorously stirred to further promote the extraction of P4HB from host cells to GBL.

[0062] In another embodiment, the slurry is optionally treated by centrifugation, sedimentation, or filtration to remove debris before being supplied to the reaction vessel (4), as shown in FIG. 4.

[0063] The terms “substantially water-removed” or “substantially water-free” are intended to indicate that the biomass introduced into the conversion reaction (i.e., the step of combining with the catalyst) contains water in an amount of about 5 wt% or less, about 4.5 wt% or less, about 4 wt% or less, about 3.5 wt% or less, about 3 wt% or less, about 2.5 wt% or less, about 2 wt% or less, about 2 wt% or less, about 1.5 wt% or less, or about 1 wt% or less, based on the weight of the biomass suspension or solution undergoing the conversion reaction. The water content of the biomass suspension or solution (present in or flowing in the system) may be measured by methods known in the art.

[0064] Although FIG. 1 illustrates the recycling stream of GBL being added to a second evaporator, the present disclosure is not limited thereto. The recycling stream of GBL may be added to another evaporator, such as a third evaporator, or to two or more evaporators. Similarly, the evaporators may include one or more, two or more, three or more, etc., and the number of evaporator columns may be determined based on the amount of starting biomass, the moisture content of the starting biomass, energy efficiency, or the total cost of the process.

[0065] Combination of practically water-removed P4HB biomass and catalyst

[0066] According to an embodiment, the P4HB biomass from which water has been substantially removed is in the form of a suspension or solution because liquid GBL functions as a solvent, and no water is added to the corresponding conversion reaction.

[0067] In the reaction vessel (4), P4HB biomass is combined with a catalyst under suitable conditions to aid in the conversion of the P4HB polymer into a high-purity gamma-butyrolactone product. The catalyst (in solid or solution form) and the biomass are combined, for example, by mixing, aggregating, centrifugation, or spray drying, or by other suitable methods known in the art to promote the interaction between the biomass and the catalyst, thereby inducing an efficient and specific conversion from P4HB to gamma-butyrolactone. “Suitable conditions” refers to conditions that promote the catalytic reaction. For example, this refers to conditions that maximize the production of the gamma-butyrolactone product, such as the presence of an auxiliary or other substance that contributes to the reaction efficiency. Other suitable conditions include conditions in which impurities, such as metals or other substances, that could hinder the progress of the reaction are absent.

[0068] As used herein, “catalyst” refers to a substance that initiates or accelerates a chemical reaction without being affected or consumed in the reaction. Examples of useful catalysts include metal catalysts. In a specific embodiment, the catalyst lowers the temperature for initiating thermal decomposition and increases the rate of thermal decomposition at a specific thermal decomposition temperature (e.g., about 190°C to about 300°C).

[0069] In some embodiments, the catalyst is a chloride, oxide, hydroxide, nitrate, phosphate, sulfate, carbonate, or stearate compound containing metal ions. Examples of suitable metal ions include aluminum, antimony, barium, bismuth, cadmium, calcium, cerium, chromium, cobalt, copper, gallium, iron, lanthanum, lead, lithium, magnesium, molybdenum, nickel, palladium, potassium, silver, sodium, strontium, tin, tungsten, vanadium, or zinc, etc. In some embodiments, the catalyst is an organic catalyst that is an amine, azide, enol, glycol, quaternary ammonium salt, phenoxide, cyanate, thiocyanate, dialkyl amide, and alkyl thioleate. In some embodiments, the catalyst is calcium hydroxide. In some embodiments, the catalyst is sodium carbonate. A mixture of two or more catalysts is also included.

[0070] In a specific embodiment, the amount of metal catalyst is about 0.1% to about 15%, or about 1% to about 25%, or 4% to about 50% based on the weight of the metal ions relative to the weight of the substantially water-removed biomass. In some embodiments, the amount of catalyst is about 7.5% to about 12%. In other embodiments, the amount of catalyst is about 0.5%, about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, or about 10%, or about 11%, or about 12%, or about 13%, or about 14%, or about 15%, or about 20%, or about 30%, or about 40%, or about 50%, or an amount between these, based on the weight of the substantially water-removed biomass.

[0071] Where used in connection with chemical reagents in any reaction, the term “sufficient amount,” as used herein, is intended to mean an amount of reference reagent capable of satisfying the required amount of the chemical reaction and the desired purity of the product.

[0072] Thermal decomposition of P4HB biomass

[0073] As used herein, “pyrolysis” and “thermolysis” refer to the thermal degradation (e.g., decomposition) of P4HB biomass for conversion to GBL. Generally, the thermal degradation of P4HB biomass occurs at elevated temperatures in the presence of a catalyst. For example, in a specific embodiment, the heating temperature for the process described herein is about 190°C to about 300°C. In some embodiments, the heating temperature is about 195°C to about 275°C, or about 200°C to about 260°C, or about 205°C to about 250°C, or about 210°C to about 225°C. In other embodiments, the heating temperature is about 190°C to 220°C. The heating temperature of the reaction vessel is generally about 50°C to 130°C, or about 60°C to 120°C, or about 70°C to 115°C, or about 80°C to 110°C, or about 85°C to 105°C, or about 90°C to 100°C, or about 100°C lower than the heating temperature of the conventional process.

[0074] "Pyrolysis" generally refers to the thermochemical decomposition of biomass at elevated temperatures for a specific period. The duration can vary from a few seconds to several hours. Under certain conditions, pyrolysis occurs in the absence of oxygen or in the presence of only a limited amount of oxygen to avoid oxygenation. The P4HB biomass pyrolysis process may involve direct or indirect heat transfer. "Flash pyrolysis" refers to the rapid heating of biomass to high temperatures for the rapid decomposition of P4HB biomass, for example, the depolymerization of P4HB in the biomass. Another example of flash pyrolysis is RTP. TM It is rapid pyrolysis. Envergent Technologies (Des Plaines, Ill.)'s RTP TM Technology and equipment convert feedstock into bio-oil.

[0075] In some embodiments, heating is performed under vacuum, at atmospheric pressure, or under controlled pressure. In certain embodiments, heating is performed using no or minimal oil-generated energy.

[0076] In a specific embodiment, heating of the P4HB biomass / catalyst mixture is performed for a time sufficient to efficiently and specifically convert the P4HB biomass to GBL. In a specific embodiment, the heating time is about 30 seconds to about 1 minute, about 30 seconds to about 1.5 minutes, about 1 minute to about 10 minutes, about 1 minute to about 5 minutes, or a time in between, e.g., about 1 minute, about 2 minutes, about 1.5 minutes, about 2.5 minutes, or about 3.5 minutes.

[0077] In another embodiment, the time is about 1 minute to about 2 minutes. In yet another embodiment, the heating duration is about 5 minutes to about 30 minutes, about 30 minutes to about 2 hours, or about 2 hours to about 10 hours, or more than 10 hours (e.g., 24 hours).

[0078] In a specific embodiment, the heating temperature is a temperature of about 190°C to about 300°C, which includes, for example, temperatures between about 195°C, about 200°C, about 205°C, about 210°C, about 215°C, about 220°C, about 225°C, about 230°C, about 235°C, about 240°C, about 245°C, about 250°C, about 255°C, about 260°C, about 270°C, about 275°C, about 280°C, and about 290°C. In a specific embodiment, the temperature is about 200°C. In a specific embodiment, the temperature is about 205°C, or about 210°C, or about 220°C, or about 230°C.

[0079] In a specific embodiment, the process also includes a step of flash pyrolyzing the residual biomass for a period sufficient to decompose at least a portion of the residual biomass into a pyrolysis liquid at a temperature, for example, 400°C or higher. In a specific embodiment, the flash pyrolysis step is performed at a temperature of about 400°C to 750°C, or about 450°C to 725°C, or about 475°C to 700°C, or about 500°C to 675°C, or about 525°C to 650°C, or about 550°C to 625°C. In some embodiments, the residence time of the residual biomass in the flash pyrolysis step is 1 second to 15 seconds, or 1 second to 5 seconds, or a time sufficient to pyrolyze the biomass to produce a desired pyrolysis precut, for example, a pyrolysis liquid.

[0080] As used herein, “pyrolysis liquid” is generally defined as a low-viscosity fluid containing sugars, aldehydes, furans, ketones, alcohols, carboxylic acids, and lignin. These materials, also known as bio-oils, are generally produced by rapid pyrolysis at a temperature sufficient to sufficiently decompose biomass into recoverable gases and liquids, which may solidify when left to stand. In some embodiments, a temperature sufficient for the decomposition of biomass is about 400°C to 800°C, or about 450°C to 750°C, or about 500°C to 700°C, or about 550°C to 650°C.

[0081] In a specific embodiment, "recovery" of gamma-butyrolactone vapor includes the condensation of said vapor. As used herein, the term "recovery" applied to vapor means separation from P4HB biomass material, which includes, but is not limited to, condensation, separation methods such as the use of membranes, gas (e.g., vapor) phase separation, such as distillation. Accordingly, recovery can be achieved through a condensation mechanism that captures monomeric component vapor, condenses said monomeric component vapor into a liquid form, and separates and delivers it from said biomass material.

[0082] As a non-limiting example, the condensation of GBL vapor can be described as follows. An incoming gas / vapor stream from the pyrolysis chamber (4) enters a distillation column (5), where the gas / vapor stream may be pre-cooled. Subsequently, the gas / vapor stream passes through a cooler, where the temperature of the gas / vapor stream is lowered by indirect contact with a refrigerant to the temperature required to condense a specified vapor from the gas. The gas and condensed vapor flow from the cooler into a condenser (7), where the condensed vapor is collected at the bottom. A portion of the vapor from the distillation column (5) or the liquid from the condenser (7) is recycled back to the evaporator as a recycled GBL stream. Now, the vapor-free gas flows out of the condenser and exits the device. The recovered liquid flows from the bottom of the condenser to a storage area or is pumped. For some products, the condensed vapor solidifies and the solid is collected.

[0083] In certain embodiments, a catalyst recovery step is additionally included in the process of the present disclosure. For example, when a calcium catalyst is used, calcination is a useful recovery technique. Calcination is a heat treatment process performed on minerals, metals, or ores to transform the material through decarboxylation, dehydration, devolatilization of organic matter, phase change, or oxidation. The process is generally carried out in a reactor such as a hearth furnace, shaft furnace, rotary kiln, or, more recently, a fluidized bed reactor. The calcination temperature is selected to be lower than the melting point of the substrate but higher than its decomposition or phase transition temperature. This is considered the temperature at which the Gibbs free energy of the reaction becomes zero. In the case of decomposing CaCO3 into CaO, the calcination temperature at △G = 0 is calculated to be ~850°C. Generally, for most minerals, the calcination temperature is in the range of about 800–1000°C or about 850–950°C, but calcination may also refer to heating performed in the range of 200–800°C.

[0084] In order to recover the calcium catalyst from the biomass after the recovery of GBL, the consumed biomass residue from the pyrolysis is directly transferred into a calcination reactor, and the biomass residue is continuously heated in the atmosphere at 825–850°C for a certain period to remove all traces of the organic biomass. Once the organic biomass is removed, the catalyst is used as is, or the metal oxides present therein (from the fermentation medium and the catalyst) can be further purified according to density using equipment known in the art.

[0085] In certain embodiments, the process may be selected for the production of a gamma-butyrolactone product containing a smaller amount of undesirable byproducts (e.g., dimerization products of GBL (3-(dihydro-2(3H)-furanylidene)dihydro-2(3H)-furanone), other oligomers of GBL, or other byproducts). For example, if a certain catalyst is used in sufficient amounts, the production of undesirable byproducts can be reduced and the yield of GBL can be increased by at least about twofold. In some embodiments, the production of undesirable byproducts will be reduced to at least about 50%, at least about 40%, at least about 30%, at least about 20%, at least about 10%, or at least about 5%. In a specific embodiment, the undesirable byproduct will be less than about 5% of the recovered GBL, less than about 4% of the recovered GBL, less than about 3% of the recovered GBL, less than about 2% of the recovered GBL, or less than about 1% of the recovered GBL.

[0086] The process described herein may provide an expression of GBL yield as a percentage yield, for example, when produced from glucose as a carbon source, the yield is up to 99%, or up to 98%, or up to 97%, or up to 96% based on the grams of GBL recovered per gram of P4HB contained in the biomass feed for the process (reported as a percentage). In other embodiments, the yield is in the range of about 60% to about 95%, for example, about 65% to about 90%, or about 70% to 90%. In other embodiments, the yield is about 98%, about 95%, about 92%, about 90%, about 88%, about 85%, about 80%, or about 75%.

[0087] As used herein, "gamma-butyrolactone" or GBL refers to a compound having the following chemical structure:

[0088]

[0089] The term "gamma-butyrolactone product" or "GBL" refers to a product containing at least about 80 to 100 weight percent of gamma-butyrolactone. For example, in a specific embodiment, the gamma-butyrolactone product may contain 95% by weight of gamma-butyrolactone and 5% by weight of by-products. In some embodiments, the amount of gamma-butyrolactone in the gamma-butyrolactone product is about 81% by weight, about 82% by weight, about 83% by weight, about 84% by weight, about 85% by weight, about 86% by weight, about 87% by weight, about 88% by weight, about 89% by weight, about 90% by weight, about 91% by weight, about 92% by weight, about 93% by weight, about 94% by weight, about 95% by weight, about 96% by weight, about 97% by weight, about 98% by weight, about 99% by weight, or about 100% by weight. In certain embodiments, the weight percentage of the gamma-butyrolactone product produced by the process described herein is 85%, or greater than 85%, or greater than 90%, or greater than 95%.

[0090] In other embodiments, the gamma-butyrolactone product may be further purified, if necessary, by additional methods known in the art, e.g., by distillation, by reactive distillation using a treatment using activated carbon to remove color and / or odor substances, by ion exchange treatment, by liquid-liquid extraction using a GBL-insoluble solvent to remove fatty acids, etc. for purification after GBL recovery, by vacuum distillation, by extractive distillation, or by similar methods to further purify the gamma-butyrolactone product to increase the gamma-butyrolactone yield. Combinations of these treatment methods may also be utilized. Specifically, the gamma-butyrolactone product may be further purified by the method disclosed in US 2014 / 0170714 A1, the contents of which are incorporated herein by reference.

[0091] In certain embodiments, GBL is further chemically modified and / or substituted with other four-carbon products (4C products) and derivatives including, but not limited to, succinic acid, 1,4-butanediamide, succinonitrile, succinamide, N-vinyl-2-pyrrolidone (NVP), 2-pyrrolidone (2-Py), N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), and 1,4-butanediol (BDO). Methods and reactions for producing such derivatives from gamma-butyrolactone are readily known to those skilled in the art.

[0092] As shown in Figures 2 and 3, the inventors demonstrated up to 30% of a 300,000 Dalton P4HB solution in the laboratory and confirmed the presence of P4HB in the solution by forming white polymer clumps by removing water to perform extraction and then pouring the solution into water. The left test tube in Figure 2 represents a 30% solution of 300,000 Dalton P4HB in GBL. The right test tube in Figure 2 represents the extract of P4HB from biomass containing GBL in Rotovap. Figure 3 shows P4HB extracted using GBL and then precipitated in water.

[0093] FIG. 4 illustrates an alternative example of the process. In addition to the evaporators (1, 2, and 3), reaction vessel (4), distillation column (5), condenser (6), and condenser (7) as shown in FIG. 1, a filter (8) or centrifuge (9) is provided between the third evaporator (3) and the reaction vessel (4). The same steps described in relation to the process illustrated in FIG. 1 are included herein by reference. The filter (8) or centrifuge (9) may be appropriately selected by a person skilled in the art.

[0094] Form for carrying out the invention

[0095] Examples

[0096] The following examples are provided for illustrative purposes only and are not intended to limit the scope of the invention.

[0097] Example 1. Production of starting biomass from genetically modified microorganisms producing poly-4-hydroxybutyrate (P4HB)

[0098] Biomass containing poly-4-hydroxybutyrate (poly-4HB) was produced in a 20 L New Brunswick Scientific fermenter (BioFlo 4500) using genetically modified E. coli strains specifically designed for the high-yield production of poly-4HB from glucose syrup as a carbon source. Examples of E. coli strains, fermentation conditions, media, and feed conditions are described in U.S. Patents No. 6,316,262; No. 6,689,589; No. 7,081,357; and No. 7,229,804, the contents of which are incorporated herein by reference. The E. coli strains produced a fermentation culture with a PHA potency of approximately 100–120 g PHA per kg of stock. After fermentation, an equal amount of water was added to the culture to wash the culture with deionized water (DI), mixed for 2 minutes, and then the water was centrifuged and drained. The washed culture medium contained approximately 10% by weight of P4HB, 10% by weight of biomass and salt, and 80% by weight of water, based on the total weight of the culture medium.

[0099] Example 2. Production of Gamma-Butyrolactone (GBL) from Starting Biomass

[0100] Next, 1000 g of the washed culture obtained in Example 1 was fed into a first evaporator and heated at 100°C for 30 minutes to remove approximately 40% of the water based on the total weight of the culture. The resulting solution was transferred to a second evaporator, where a recycled GBL stream was fed to replace the water removed in the first evaporator. The mixture was heated at 100°C for 30 minutes to remove an additional approximately 40% of the water based on the total weight of the culture. The resulting solution was transferred to a third evaporator and heated at 100°C for 20 minutes to remove the remaining water. The resulting slurry contained, based on the total weight of the slurry, approximately 25% by weight of P4HB, approximately 25% by weight of biomass and salt, approximately 47% by weight of GBL, and less than 3% of water.

[0101] Although not essential, filtration was performed on the slurry (a biomass solution / suspension from which water had been substantially removed) to further increase the purity of the GBL product. Through filtration, a polymer solution was obtained containing, based on the total weight of the polymer solution, approximately 30% by weight of P4HB, approximately 3% by weight of biomass and salt, and approximately 66% by weight of GBL.

[0102] A filtered, substantially dewatered biomass solution was mixed with lime (98% Ca(OH)2 standard hydrated lime, Mississippi Lime) targeting a weight of 4% based on P4HB. The thermal decomposition of GBL+P4HB+Ca(OH)2 was performed using a flask equipped with a stirrer, either under vortexing or while stirring at 200–250°C. At the start of the process, a weighed sample of GBL+P4HB+Ca(OH)2 was placed into the flask, and nitrogen purge flow was set. Subsequently, stirring and heating were initiated. When the temperature of the flask reaches its setpoint (e.g., about 204°C), the gas generated by the GBL+P4HB+Ca(OH)2 sample is swept out of the flask by nitrogen purging and enters a series of glass condensers or cooling traps. The condensers consisted of a vertical cooled glass condenser tower equipped with a condensate collection bulb at its bottom. A glycol / water mixture maintained at 0°C was circulated through the entire glass condenser. The cooled gas exiting from the top of the first condenser was directed downward through the second condenser and the second condensate collection bulb, and then bubbled through a glass impinger (dust collector) filled with deionized water.

[0103] The total pyrolysis run time was about 60 minutes.

[0104] After the pyrolysis run was completed, the condensate from the condenser was collected and weighed. The results indicated that the combined weight of the condensate was approximately 240 g. Karl Fisher moisture analysis and GC-MS analysis of the condensate revealed that the condensate contained 3% water and 0.06% fatty acids, with the remainder being GBL products. Accordingly, the GBL product yield ((g of GBL product / g of starting P4HB) × 100%) was calculated to be approximately 87%. Impurities, such as GBL dimers, organic-sulfur, and amide compounds, were not detected in the condensate using GC-MS, indicating that the purity of the GBL product from the pyrolysis was approximately 99%.

[0105] Experiments were conducted to confirm that the process according to the embodiment, which uses recycled GBL for the production of substantially water-removed biomass solution / suspension and performs a conversion process thereon, surprisingly effectively converts P4HB to GBL. Some Sigma GBL was doped with a known amount of Undecane. Spray-dried P4HB biomass was added to Sigma GBL, heated to 190°C under reflux, and maintained for 6 hours. Samples (GBL KS-1, KS-2, KS-3, and KS-4) were collected at reaction times of 0, 30, 90, and 300 minutes and analyzed to determine the GBL to Undecane ratio. Table 1 below shows that the ratio of Undecane to GBL ("Ratio" column) and the Undecane level (PPM UD) decrease as time progresses from time 0 to time 300 minutes.

[0106]

[0107] Example 3. Post-purification of bio-based GBL by distillation, steam stripping, and peroxide treatment

[0108] This example briefly describes an optional procedure for purifying a bio-based GBL liquid prepared from the pyrolysis of a genetically modified microorganism that produces a poly-4-hydroxybutyrate polymer mixed with a catalyst, as outlined in Example 2 above. It should be noted that since the product from Example 2 is already highly pure, the corresponding distillation purification process may not be necessary.

[0109] GBL purification is a batch process in which the "crude" GBL liquid recovered after pyrolysis is first filtered to remove solid particulates (typically <1% of the total crude GBL weight), and then distilled twice to remove compounds affecting odor and color.

[0110] Filtration of crude GBL liquid is performed on a laboratory scale using a Buchner fritted-glass funnel coupled to an Erlenmeyer receiving flask. Approximately 1 liter of crude GBL was filtered to produce approximately 0.99 liters of recovered GBL liquid.

[0111] Distillation of the filtered GBL liquid is performed using a high-vacuum 20-stage glass distillation column. The stage sections of the column are contained within silver-coated, vacuum-insulated glass sleeves to minimize heat loss from the column during the distillation process. Distillation is performed under vacuum conditions using a vacuum pump equipped with a liquid nitrogen cold trap. The typical column operating pressure during distillation is in the 25-inch Hg range. Cooling water maintained at 10°C passes through the condenser at the top of the column to aid in the fractionation of the vapor. The column is also equipped with two thermocouples: one is mounted at the top of the column to monitor the vapor temperature, and the other is mounted at the bottom of the column to monitor the liquid feed temperature. When distillation begins, approximately 1 liter of filtered GBL liquid is filled into the bottom of the column, the condenser cooling water is activated, and then the vacuum is turned on. Once the pressure stabilizes, the filtered GBL liquid is slowly heated to the boiling point of GBL (204°C) using a heating mantle.

[0112] During the initial stage of distillation, water contained in the filtered GBL is first removed and discarded along with lower boiling impurities. When the water and lower boiling impurities are completely removed, the temperature of the GBL liquid feed increases to the boiling point of the GBL. At this stage, the vapor generated at the top of the column is mostly GBL, which is condensed, collected, and stored for further distillation. Distillation is stopped when it is observed that the temperature of the liquid feed has rapidly increased above 204°C. The total amount of GBL liquid recovered from the first distillation is 0.9 liters, and its purity is 97%.

[0113] Another variation for the second distillation is attempted by adding 1–3% (by GBL weight) of a 30% hydrogen peroxide solution to the previously distilled GBL liquid along with deionized water. The peroxide acts to oxidize impurities in the GBL liquid, reducing volatility and thereby facilitating separation. To perform this distillation, 0.9 liters of the previously distilled GBL liquid are added to the bottom of the distillation column along with 203 g of deionized water and 10.2 g of 30–32% hydrogen peroxide (Sigma Aldrich). Condenser cooling water and vacuum are applied, and the GBL liquid feed is heated. The distillation produced a first water fraction and a second transition fraction before the pure GBL vapor. Both the first and second fractions are discarded, and the pure GBL liquid is collected. Analysis of the GBL liquid by GC-MS revealed a purity of >99.5% with very low odor and color. To remove additional water, the purified GBL liquid can be stored in a dry molecular sieve (pore size 3–4 Å, Sigma Aldrich) until use. A portion of the GBL liquid purified in this way is recycled back to the evaporator of Example 2.

[0114] Table 2 below summarizes the heat balance of a conventional process ("Basic Case Process"), which includes a drying step of the starting biomass using a spray dryer to evaporate most of the water from the fermentation, compared to the process of Example 2. As can be seen from Table 1, as the recycling rate (recycled GBL / product GBL) increases, the required evaporator surface area decreases, and heat from the recycled GBL can be efficiently used for evaporation.

[0115]

[0116] Another variation of the aforementioned purification step is to add deionized water and / or a 30% hydrogen peroxide solution during the first distillation step. Additional purification steps may include treatment using ozone, ion exchange resin, or activated carbon.

[0117] In another embodiment, it is also possible to produce corresponding diols, hydroxyl esters, and amides (e.g., 1,4-butanediol, alkyl 4-hydroxybutyrate, or N-alkyl 2-pyrrolidone, respectively, when hydrogenation using H2, esterification using alkyl alcohols, and amidation using alkyl amines) by directly applying hydrogenation, esterification using alkyl alcohols, and amidation using alkyl amines.

[0118] The processing of fats and oils for alcohol production provides several guidelines in this regard. Oils and fats are important sources of fatty alcohols used in various applications, such as lubricants and surfactants. Fats are generally not hydrogenated directly, as high-intensity reaction conditions tend to degrade glycerol into lower alcohols such as propylene glycol and propanol. For this reason, to enable more efficient hydrogenation, it is more common to preferentially hydrolyze oils and then pre-refine fatty acids (see, for example, Lurgi's hydrogenation process in Bailey's Industrial Oil and Fat Products (Sixth Edition, Six Volume Set. Edited by Fereidoon Shahidi, John Wiley & Sons, Inc. 2005)).

[0119] Although the subject matter disclosed herein has been described in relation to what is considered to be a practical exemplary embodiment, the present disclosure is not limited to the disclosed embodiments and should be understood to include various modifications and equivalent arrangements that fall within the spirit and scope of the appended claims.

[0120] Unless otherwise exemplified or otherwise specified herein, all numerical ranges, amounts, values, and percentages regarding the amount of a substance, element content, reaction time and temperature, ratio of amount, etc. in the foregoing parts of this specification and the appended claims may be understood as being preceded by the word “about” even if the word “about” does not explicitly appear with respect to such values, amounts, or ranges.

[0121] Accordingly, unless otherwise indicated, the numeric parameters set forth in the foregoing specification and appended claims are approximations that may vary depending on the desired characteristics to be obtained through the present invention. At the very least, each numeric parameter should be interpreted by taking into account at least the reported number of significant digits and applying general rounding techniques, not as an attempt to limit the application of the equivalence principle to the scope of the claims.

[0122] Although the numerical ranges and parameters describing the broad scope of the invention are approximations, the numerical values ​​presented in specific examples are reported as accurately as possible. However, all numerical values ​​contain errors that inevitably arise due to the standard deviation inherent in each test measurement. Additionally, where numerical ranges are presented herein, these ranges include the endpoints of the cited ranges (i.e., endpoints may be used). Where weight-based percentages are used herein, the reported numerical values ​​are values ​​relative to the total weight.

[0123] Additionally, any numerical range cited herein is to be understood as including all sub-ranges contained therein. For example, the range “1 to 10” is intended to include all sub-ranges between (and including) the cited minimum value 1 and the cited maximum value 10, that is, everything where the minimum value is 1 or greater and the maximum value is 10 or less. Unless otherwise specified, the terms “one,” “one,” or “one” as used herein are intended to include “at least one” or “one or more.”

Claims

Claim 1 A method for producing a gamma-butyrolactone (GBL) product from water and a starting biomass containing poly-4-hydroxybutyrate (P4HB) cells, the method comprising: (a) introducing the starting biomass into an evaporator; (b) introducing liquid or vapor GBL into the evaporator as a solvent in an amount equal to or less than the weight of the removed water to obtain a biomass suspension or solution containing P4HB dissolved or suspended in the GBL from which the water has been removed; (c) combining the water-removed biomass suspension or solution with a conversion catalyst and heating the resulting mixture to convert the P4HB into GBL; and (d) collecting the GBL, wherein the liquid or vapor GBL introduced in step (b) is recycled GBL that is part of the GBL collected in step (d), which is recycled back into the evaporator and mixed with the biomass as a solvent, and the method does not include a drying step. Claim 2 The method of claim 1, further comprising (e) a mixing, stirring, vortexing, or strong stirring step to promote the extraction of P4HB from host cells into GBL. Claim 3 A method according to claim 1, further comprising, prior to step (c), (f) a step of removing solids from a biomass suspension or solution from which water has been removed by filtration, sedimentation, or centrifugation. Claim 4 A method according to claim 1, wherein water is not added in steps (a), (b) and (c). Claim 5 A method according to claim 1, wherein the evaporator comprises a plurality of series evaporators fluidly connected to each other, and the recycled GBL is introduced into one or more of the evaporators. Claim 6 A method according to claim 1, wherein the evaporator comprises a first evaporator, a second evaporator and a third evaporator, wherein the evaporators are fluidly connected to each other in series in the corresponding order, and the recycled GBL is introduced into the second evaporator and / or the third evaporator. Claim 7 A method according to claim 1, wherein step (a) is performed at a temperature of 60°C to 100°C under vacuum or atmospheric pressure. Claim 8 A method according to claim 6, wherein 20 to 50% of the water contained in the starting biomass is removed in the first evaporator, 20 to 45% of the water contained in the starting biomass is removed in the second evaporator, and 5 to 35% of the water contained in the starting biomass is removed in the third evaporator; wherein the recycled GBL is introduced to replace the water removed from the first and second evaporators. Claim 9 The method according to claim 1, wherein the biomass solution or suspension from which water has been removed comprises a water content of 5% by weight or less based on the weight of the biomass solution or suspension. Claim 10 A method according to claim 1, wherein step (a) is performed at a temperature of 70°C to 90°C under vacuum. Claim 11 A method according to claim 1, wherein step (a) is performed in a time cycle of 5 minutes to 2 hours. Claim 12 A method according to claim 1, wherein the GBL collected in step (d) comprises less than 5% by weight of by-products. Claim 13 A method according to claim 1, wherein the conversion of step (c) is performed in the presence of a catalyst. Claim 14 In paragraph 13, the method wherein the catalyst is sodium carbonate or calcium hydroxide. Claim 15 A method according to claim 1, wherein the yield of the GBL product is 85% or more by weight based on 1 gram of GBL among the converted products per gram of P4HB. Claim 16 The method of claim 1, wherein the starting biomass is genetically engineered biomass from a host cell containing a non-naturally occurring amount of P4HB. Claim 17 delete Claim 18 delete

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