Method for producing long-chain fatty acids and its use

Abstract

The purpose of the present invention is to provide a method that is for producing long-chain fatty acids and that enable prevention of a coloring component from being contained and enable high yield recovery of long-chain fatty acids. Provided is a method that is for producing long-chain fatty acids and that comprises: (a) a step for decomposing triglycerides, in crude plant oil derived from waste products containing plant-derived oil, into fatty acids by using an enzyme; (b) a step for removing, through distillation, short-chain fatty acids in the crude plant oil after step (a); and (c) a step for recovering long-chain fatty acids in the crude plant oil after step (b) by short path distillation.

Description

Technical Field

[0001] The present invention relates to a method for producing long-chain fatty acids and their use.

Background Art

[0002] Long-chain fatty acids are used in various applications as food additives, carbon sources for biological cultures, etc. As a raw material rich in long-chain fatty acids, palm oil produced from oil palm is typical, but there are many problems as its plantation expansion often involves environmental destruction.

[0003] On the other hand, from the perspective of Life Cycle Assessment (LCA), in order to reduce CO2, the recovery of long-chain fatty acids from waste as a raw material is desired.

[0004] For example, Patent Document 1 describes a method for producing palm-based oils having an iodine value of 58 or more and a γ-tocotrienol content of 78 ppm or less.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, there is room for improvement in the technology for recovering long-chain fatty acids from waste raw materials.

[0007] Therefore, an object of the present invention is to provide a novel production method capable of reducing the content of coloring components and recovering long-chain fatty acids in a high yield.

Means for Solving the Problems

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that after decomposing triglycerides in crude vegetable oil into fatty acids with an enzyme, removing short-chain fatty acids in the crude vegetable oil by distillation, and then recovering long-chain fatty acids in the crude vegetable oil by short-path distillation, it is possible to produce long-chain fatty acids with a high recovery rate and low chromaticity, and thus have completed the present invention.

[0009] Therefore, one aspect of the present invention relates to a production method including: (a) a step of decomposing triglycerides in crude vegetable oil derived from waste containing plant-derived oil into fatty acids using an enzyme; (b) a step of removing short-chain fatty acids in the crude vegetable oil after the step (a) by distillation; and (c) a step of recovering long-chain fatty acids in the crude vegetable oil after the step (b) by short-path distillation. Weight of long-chain fatty acids obtained in the step (c) / Total weight of fatty acids and triglycerides in the crude vegetable oil in the step (a) × 100... (1)

Effects of the Invention

[0010] According to one aspect of the present invention, it is possible to suppress the content of coloring components and recover long-chain fatty acids in a high yield.

Modes for Carrying Out the Invention

[0011] One embodiment of the present invention will be described in detail below. Unless otherwise specified in this specification, "A to B" representing a numerical range means "A or more and B or less". Further, all documents described in this specification are incorporated herein by reference.

[0012] 〔1. Outline of the Present Invention〕 A method for producing long-chain fatty acids according to an embodiment of the present invention (hereinafter referred to as "this production method") includes: (a) a step of decomposing triglycerides in crude vegetable oil derived from waste containing plant-derived oil into fatty acids using an enzyme; (b) a step of removing short-chain fatty acids in the crude vegetable oil after the step (a) by distillation; and (c) a step of recovering long-chain fatty acids in the crude vegetable oil after the step (b) by short-path distillation. Weight of long-chain fatty acids obtained in the step (c) / Total weight of fatty acids and triglycerides in the crude vegetable oil in the step (a) × 100... (1) When the present inventor was proceeding with the study on the technology for recovering long-chain fatty acids from waste raw materials, the inventor focused on waste containing plant-derived oil as the raw material. Although waste containing plant-derived oil contains a large amount of long-chain fatty acids, various impurities are contained, and the following problems were found. · Due to the presence of impurities, the recovery rate of long-chain fatty acids is low · Due to the presence of impurities having coloring components, it is difficult to obtain long-chain fatty acids with low chromaticity Therefore, as a result of intensive studies on a production method capable of reducing the content of coloring components and recovering long-chain fatty acids in a high yield, the present inventor succeeded in obtaining the following findings. · By a production method including a step of decomposing triglycerides in crude vegetable oil into fatty acids using an enzyme, a step of removing short-chain fatty acids in the crude vegetable oil by distillation, and a step of recovering long-chain fatty acids in the crude vegetable oil by short-path distillation, a high recovery rate (for example, the recovery rate of long-chain fatty acids represented by the following formula (1) is 40% or more: Weight of long-chain fatty acids obtained in the step (c) / Total weight of fatty acids and triglycerides in the crude vegetable oil in the step (a) × 100... (1)) and long-chain fatty acids with low chromaticity (for example, 700 or less) can be produced.

[0013] Thus, according to this production method, since the content of coloring components can be reduced and long-chain fatty acids can be recovered in a high yield, it is extremely advantageous in the production of long-chain fatty acids. Hereinafter, the configuration of this production method will be described in detail.

[0014] [2. Method for Producing Long-Chain Fatty Acids] This production method is a method for producing long-chain fatty acids, including the following steps (a) to (c) as essential steps. · Step (a): A step of decomposing triglycerides in crude vegetable oil derived from waste containing plant-derived oil into fatty acids using an enzyme · Step (b): A step of removing short-chain fatty acids in the crude vegetable oil after step (a) by distillation · Step (c): A step of recovering long-chain fatty acids in the crude vegetable oil after step (b) by short-path distillation According to this production method, the content of coloring components can be suppressed, and long-chain fatty acids can be recovered in a high yield. In this specification, "long-chain fatty acids" means fatty acids having 9 or more carbon atoms. The long-chain fatty acids may originally be contained in waste containing plant-derived oil, or may be produced by decomposing triglycerides contained in waste containing plant-derived oil. The long-chain fatty acids are not particularly limited as long as they are fatty acids having 9 or more carbon atoms, but are preferably fatty acids having 12 or more carbon atoms, more preferably fatty acids having 15 or more carbon atoms, and particularly preferably fatty acids having 18 or more carbon atoms. In one embodiment of the present invention, examples of the long-chain fatty acids include lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid, erucic acid, and the like.

[0015] In one embodiment of the present invention, the long-chain fatty acids can be at least one or more selected from the group consisting of lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid.

[0016] (Step (a)) In step (a) of this production method, triglycerides in crude vegetable oil derived from waste containing plant-derived oil are decomposed into fatty acids using an enzyme.

[0017] As used herein, "waste containing plant-derived oil" means the remaining part of a plant excluding the valuable parts thereof and containing an oil-containing part. For example, when producing edible palm oil from oil palm as a plant raw material, the inedible palm oil excluding the edible palm oil corresponds to the waste containing plant-derived oil. The waste containing plant-derived oil is not particularly limited as long as it satisfies the above definition, and examples thereof include soybean meal, rapeseed meal, sunflower meal, coffee grounds, cocoa husks, sesame oil meal, cottonseed meal, tea seed meal, POME (Palm Oil Mill Effluent ), PKS (Palm Kernel Shell), EFB (Empty Fruit Bunch), grape pomace, olive pomace, tomato pomace, sake lees, shochu lees, starch residue, whisky waste liquid, beer residue, soy sauce residue, and the like.

[0018] In one embodiment of the present invention, the waste containing plant-derived oil may contain at least one selected from the group consisting of water, solids, short-chain fatty acids, triglycerides, long-chain fatty acids, vitamin E, and carotenoids.

[0019] As used herein, "crude vegetable oil" means a roughly refined oil containing fat-soluble components obtained from waste containing plant-derived oil. In one embodiment of the present invention, the crude vegetable oil contains at least fatty acids and triglycerides. The measurement of the components contained in the crude vegetable oil can be easily performed using ordinary methods such as high performance liquid chromatography, gas chromatography, and Robivond automatic colorimeter.

[0020] As used herein, "triglyceride" means a neutral fat in which three molecules of fatty acid are ester-bonded to one molecule of glycerin. The fatty acid constituting the triglyceride is preferably the long-chain fatty acid which is the target product in the present production method.

[0021] In step (a), the triglyceride is decomposed into fatty acids by an enzyme. The enzyme used in step (a) is not particularly limited as long as it has the function of decomposing triglycerides into fatty acids and glycerol. Examples of such enzymes include lipase and the like. As lipase, many types with different decomposition specificities can be mentioned due to the diversity of the substrate triglyceride. From the viewpoint of suppressing the accumulation of monoglyceride and diglyceride, which are hydrolysis products, preferably, it is a lipase that has no specificity for the three ester bonds (α, β, α' positions) and has a wide stable range with respect to pH and temperature, such as triacylglycerol lipase EC 3.1.1.3, phospholipase A2, galactolipase, lipoprotein lipase, acylglycerol lipase.

[0022] In one embodiment of the present invention, the enzyme used in step (a) may be an enzyme contained in a microorganism. That is, in step (a), a microorganism having the above enzyme can also be used.

[0023] In step (a), the treatment time with the enzyme, the addition amount of the enzyme, the reaction temperature, etc. can be appropriately set by those skilled in the art.

[0024] In one embodiment of the present invention, the triglyceride decomposition rate in step (a) is, for example, 90 to 100%, preferably 95 to 100%, and more preferably 97 to 100%. When the triglyceride decomposition rate is within the above range, it has the advantage that long-chain fatty acids can be recovered in a high yield. The triglyceride decomposition rate is measured and calculated by the method described in the examples.

[0025] (Step (a')) In one embodiment of the present invention, this production method may include the following step (a') before the above step (a). · Step (a'): A step of separating waste containing plant-derived oil into an oil phase, an aqueous phase, and a solid phase, and removing the aqueous phase and the solid phase to obtain crude vegetable oil In step (a’), the separation of the waste containing plant-derived oil can be carried out using any method in the relevant technical field without particular limitation. For example, it can be carried out using a commercially available three-phase separation decanter (manufactured by IHI Corporation) described in the examples.

[0026] Each phase (oil phase, water phase, and solid phase) separated in step (a’) is the phase shown below. · Oil phase: The phase containing fat-soluble components such as fatty acids and triglycerides · Water phase: The phase containing water-soluble components such as potassium, sodium, calcium, and magnesium · Solid phase: The phase containing solid components other than the components contained in the above oil phase and water phase In step (a’), after separating into the above oil phase, water phase, and solid phase, crude vegetable oil can be obtained by removing the water phase and solid phase. In step (a’), the method for removing the water phase and solid phase is not particularly limited, and any method in the relevant technical field can be used to remove the water phase and solid phase.

[0027] Note that the crude vegetable oil in step (a’) is the same as that described in the above section (step (a)).

[0028] (Step (b)) In step (b) of the present production method, short-chain fatty acids in the crude vegetable oil after step (a) are removed by distillation.

[0029] In this specification, “short-chain fatty acid” means a fatty acid having 8 or fewer carbon atoms. The short-chain fatty acid is not particularly limited as long as it is a fatty acid having 8 or fewer carbon atoms, but is preferably a fatty acid having 6 or fewer carbon atoms, more preferably a fatty acid having 5 or fewer carbon atoms, and particularly preferably a fatty acid having 4 or fewer carbon atoms. In one embodiment of the present invention, examples of the short-chain fatty acid include butyric acid, propionic acid, isobutyric acid, isovaleric acid, valeric acid, caproic acid, lactic acid, succinic acid, acetic acid, etc.

[0030] In one embodiment of the present invention, the short-chain fatty acid may be at least one selected from the group consisting of butyric acid, propionic acid, isobutyric acid, isovaleric acid, valeric acid, caproic acid, lactic acid, and succinic acid.

[0031] Long-chain fatty acids contained in plant-derived oil-containing waste (e.g., EFB) are often decomposed at 230 to 280°C. Therefore, the distillation temperature in step (b) is preferably carried out at a temperature lower than 230°C. The distillation temperature in step (b) is, for example, less than 230°C, preferably 220°C or lower, and more preferably 210°C or lower. When the distillation temperature in step (b) is within the above range, there is an advantage that short-chain fatty acids can be removed while avoiding the decomposition of long-chain fatty acids.

[0032] Many short-chain fatty acids are classified as odor components. Therefore, step (b) has the advantage that odor components in the crude vegetable oil can be removed, and as a result, odorless long-chain fatty acids can be obtained.

[0033] In one embodiment of the present invention, the removal rate of short-chain fatty acids in step (b) is, for example, 90 to 100%, preferably 95 to 100%, and more preferably 98 to 100%. When the removal rate of short-chain fatty acids is within the above range, there is an advantage that odorless long-chain fatty acids can be obtained. The removal rate of short-chain fatty acids is measured by the method described in the examples.

[0034] In step (b), the distillation is not particularly limited and can be carried out using any method in the technical field. The distillation can be carried out, for example, by simple distillation, continuous distillation, etc., as described in the Chemical Engineering Handbook published by Maruzen Co., Ltd.

[0035] (Step (c)) In step (c) of the present production method, the long-chain fatty acids in the crude vegetable oil after step (b) are recovered by short-path distillation.

[0036] In this specification, "short-path distillation" is synonymous with short-path distillation generally used in the art. That is, short-path distillation means heating under reduced pressure to perform evaporation. By this treatment, the raw material (in step (c), "crude vegetable oil after step (b)") can be separated into a distillate and a residue. The distillate contains long-chain fatty acids with relatively low boiling points, and the residue contains coloring components with relatively high boiling points (for example, β-carotene, tocotrienol, tocopherol, etc.). Stroke And perform evaporation by heating under reduced pressure as follows. By this treatment, the raw material (in step (c), "crude vegetable oil after step (b)") can be separated into a distillate and a residue. The distillate contains long-chain fatty acids with relatively low boiling points, and the residue contains coloring components with relatively high boiling points (for example, β-carotene, tocotrienol, tocopherol, etc.).

[0037] In step (c), by setting the pressure inside the short-path distillation apparatus (hereinafter, may also be referred to as "short-path evaporator") and / or the wall temperature of the short-path distillation apparatus within a specific range, contamination by coloring components can be avoided as much as possible, and only long-chain fatty acids can be recovered.

[0038] In one embodiment of the present invention, the pressure inside the short-path distillation apparatus in step (c) is, for example, 5 to 250 Pa, preferably 5 to 200 Pa, and more preferably 10 to 100 Pa.

[0039] In one embodiment of the present invention, the wall temperature of the short-path distillation apparatus in step (c) is, for example, 150 to 200 °C, preferably 155 to 198 °C, and more preferably 160 to 195 °C.

[0040] In one embodiment of the present invention, the preferable range of the wall temperature of the short-path distillation apparatus in step (c) may vary according to the pressure inside the short-path distillation apparatus. For example, when the pressure inside the short-path distillation apparatus is 5 to 30 Pa, the wall temperature of the short-path distillation apparatus is, for example, 150 to 180°C, preferably 152 to 178°C, and more preferably 155 to 175°C. Further, when the pressure inside the short-path distillation apparatus exceeds 30 Pa and is 250 Pa or less, the wall temperature of the short-path distillation apparatus is, for example, 170 to 200°C, preferably 172 to 198°C, and more preferably 174 to 195°C. When the pressure and the wall temperature inside the short-path distillation apparatus are within the above ranges, it is possible to recover long-chain fatty acids in a high yield while avoiding contamination with coloring components.

[0041] In one embodiment of the present invention, the short-path distillation in step (c) can be carried out at a wall temperature of the apparatus of 150 to 180°C under an internal pressure of the apparatus of 5 to 30 Pa, or at a wall temperature of the apparatus of 170 to 200°C under an internal pressure of the apparatus exceeding 30 Pa and 250 Pa or less.

[0042] The short-path distillation apparatus used in the short-path distillation is not particularly limited, and examples thereof include evaporators such as a falling liquid film type, a centrifugal type, a rising liquid film type, and a wiped film type. For example, as the short-path distillation apparatus, a short-path distiller manufactured by UIC, which is described in the examples below, can be used.

[0043] (Others)) The long-chain fatty acids obtained by this production method have a low chromaticity. Further, according to this production method, a high recovery rate of long-chain fatty acids is enabled.

[0044] In one embodiment of the present invention, the chromaticity of the long-chain fatty acid is, for example, 700 or less, preferably 600 or less, more preferably 500 or less, and particularly preferably 460 or less. When the chromaticity of the long-chain fatty acid is within the above range, a long-chain fatty acid with sufficiently little coloring can be obtained. For example, when used in the production of polyhydroxyalkanoic acid described later, it has the advantage of suppressing the quality deterioration of polyhydroxyalkanoic acid. Further, the lower the chromaticity of the long-chain fatty acid, the better, and the lower limit is not particularly limited, but is, for example, 50 or more. The chromaticity of the long-chain fatty acid is measured by the method described in the examples.

[0045] The recovery rate of the long-chain fatty acid by this production method is represented by the following formula (1).

[0046] Weight of the long-chain fatty acid obtained in step (c) / Total weight of fatty acids and triglycerides in the crude vegetable oil in step (a) × 100... (1) "The crude vegetable oil in step (a)" in formula (1) means "the crude vegetable oil before the enzyme treatment in step (a)". Therefore, "the total weight of fatty acids and triglycerides in the crude vegetable oil in step (a)" in formula (1) means "the total weight of fatty acids and triglycerides in the crude vegetable oil before the enzyme treatment in step (a)". Further, "Weight of the long-chain fatty acid obtained in step (c) / Total weight of fatty acids and triglycerides in the crude vegetable oil in step (a) × 100" can also be described as "Weight of the recovered long-chain fatty acid / Total weight of fatty acids and triglycerides in the crude vegetable oil × 100".

[0047] In one embodiment of the present invention, the recovery rate of the long-chain fatty acid may be 40% or more, preferably 55% or more, more preferably 60% or more, and still more preferably 65% or more. When the recovery rate of the long-chain fatty acid is within the above range, it has the advantage of obtaining the long-chain fatty acid at low cost and efficiently. Further, the higher the recovery rate of the long-chain fatty acid, the better, and the upper limit is not particularly limited, but is, for example, 100% or less. The recovery rate of the long-chain fatty acid is measured by the method described in the examples.

[0048] The concentration of long-chain fatty acids in the fatty acids by this production method is represented by the following formula (2).

[0049] Amount of long-chain fatty acids obtained in step (c) / Amount of fatty acids obtained in step (c) × 100 ··· (2) Note that "Amount of long-chain fatty acids obtained in step (c) / Amount of fatty acids obtained in step (c) × 100" can also be described as "Amount of recovered long-chain fatty acids / Amount of recovered fatty acids × 100".

[0050] In one embodiment of the present invention, the concentration of long-chain fatty acids in the fatty acids is, for example, 93% or more, preferably 94% or more, more preferably 95% or more, still more preferably 96% or more, and particularly preferably 99% or more. When the concentration of long-chain fatty acids in the fatty acids is within the above range, there is an advantage that long-chain fatty acids can be obtained at low cost and efficiently. Also, the higher the concentration of long-chain fatty acids in the fatty acids, the better, and the upper limit is not particularly limited, but is, for example, 100% or less. Note that the concentration of long-chain fatty acids in the fatty acids is measured by the method described in the examples.

[0051] [3. Method for producing polyhydroxyalkanoic acid] In one embodiment of the present invention, provided is a method for producing polyhydroxyalkanoic acid (hereinafter referred to as "PHA") including a step of culturing a microorganism having the ability to produce PHA using the long-chain fatty acids obtained by this production method (conveniently referred to as "step (i)") (hereinafter referred to as "this PHA production method"). In this PHA production method, since the long-chain fatty acids obtained by this production method with sufficiently little coloring are used, there is an advantage that a decrease in the quality of polyhydroxyalkanoic acid can be suppressed.

[0052] As used herein, "PHA" is a general term for polymers having hydroxyalkanoic acids as monomer units. The hydroxyalkanoic acids constituting PHA are not particularly limited, and examples thereof include 3-hydroxybutanoic acid, 4-hydroxybutanoic acid, 3-hydroxypropionic acid, 3-hydroxypentanoic acid, 3-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, 3-hydroxyoctanoic acid, and the like. These polymers may be homopolymers or copolymers containing two or more monomer units.

[0053] More specifically, examples of PHA include poly(3-hydroxybutyrate) (P3HB), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P3HB3HV), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) (P3HB3HO), poly(3-hydroxybutyrate-co-3-hydroxyoctadecanoate) (P3HB3HOD), poly(3-hydroxybutyrate-co-3-hydroxydecanoate) (P3HB3HD), poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (P3HB3HV3HH), and the like.

[0054] The microorganisms having PHA-producing ability used in the method for producing the present PHA are not particularly limited as long as they are microorganisms capable of producing PHA intracellularly. For example, microorganisms isolated from nature, microorganisms deposited in a microorganism depository institution (e.g., IFO, ATCC, etc.), or mutants, transformants, etc. that can be prepared therefrom can be used. More specifically, examples thereof include bacteria belonging to the genus Cupriavidus, Alcaligenes, Ralstonia, Pseudomonas, Bacillus, Azotobacter, Nocardia, Aeromonas, and the like.

[0055] In addition, when the microorganism does not originally have the ability to produce PHA or has a low PHA production amount, a transformant obtained by introducing the target PHA synthase gene and / or its variant into the microorganism can also be used. Such a transformant is also included in the microorganisms having the PHA-producing ability used in the method for producing the present PHA. The PHA synthase gene used for producing the transformant is not particularly limited, but the gene of the PHA synthase derived from Aeromonas caviae is preferred.

[0056] By culturing the above-mentioned microorganism having the PHA-producing ability under appropriate conditions, microbial cells in which PHA is accumulated in the cells can be obtained. The method for culturing the microbial cells is not particularly limited, but for example, the method described in JP-A-05-93049 or the like is used.

[0057] In one embodiment of the present invention, the method for producing the present PHA may include a PHA purification step (conveniently referred to as "step (ii)") after step (i). Since the microorganism cultured in step (i) contains a large amount of cell-derived components as impurities in addition to PHA, it is preferable to include a purification step for decomposing and / or removing impurities other than PHA. This purification step is not particularly limited, and physical treatments, chemical treatments, biological treatments, etc. that can be conceived by those skilled in the art can be applied. As the purification step, for example, the purification method described in International Publication No. 2010 / 067543 can be preferably applied.

[0058] In one embodiment of the present invention, the method for producing the present PHA may further include a PHA drying step (conveniently referred to as "step (iii)") after step (ii). This drying step is not particularly limited, and any method that can be conceived by those skilled in the art can be applied. As the drying step, for example, spray drying using a spray dryer can be applied. By step (iii), the particle size of PHA can be appropriately adjusted according to the subsequent use purpose. Adjustment adjusted.

[0059] The PHA obtained by the method for producing PHA of the present invention can be used for various applications such as paper, film, sheet, tube, plate, rod, container (e.g., bottle container, etc.), bag, parts, etc.

[0060] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0061] That is, one embodiment of the present invention is as follows. <1> (a) A step of decomposing triglycerides in crude vegetable oil derived from waste containing plant-derived oil into fatty acids using an enzyme, (b) A step of removing short-chain fatty acids in the crude vegetable oil after the step (a) by distillation, and (c) A step of recovering long-chain fatty acids in the crude vegetable oil after the step (b) by short-path distillation, a method for producing long-chain fatty acids. <2> The chromaticity of the long-chain fatty acid is 700 or less, and The recovery rate of the long-chain fatty acid represented by the following formula (1) is 40% or more, the method for producing a long-chain fatty acid according to <1>.

[0062] Weight of the long-chain fatty acid obtained in the step (c) / Total weight of fatty acids and triglycerides in the crude vegetable oil in the step (a) × 100... (1) <3> The concentration of long-chain fatty acids in the fatty acid represented by the following formula (2) is 99.0% or more, the method for producing a long-chain fatty acid according to <1> or <2>.

[0063] The long Lock Amount of fatty acid obtained in the step (c) / Amount of fatty acid obtained in the step (c)... (2) <4> Before the step (a), the method for producing a long-chain fatty acid according to any one of <1> to <3>, including the following step (a'): (a') Separating waste containing plant-derived oil into an oil phase, an aqueous phase, and a solid content phase, and removing the aqueous phase and the solid content phase to obtain crude vegetable oil. <5>In the step (c), the short-path distillation is carried out (i) at an internal pressure of the apparatus of 5 to 30 Pa and a wall temperature of the apparatus of 150 to 180 °C, or (ii) at an internal pressure of the apparatus of more than 30 Pa and 250 Pa or less and a wall temperature of the apparatus of 170 to 200 °C, and the method for producing a long-chain fatty acid according to any one of <1> to <4>. <6>The method for producing a long-chain fatty acid according to any one of <1> to <5>, wherein the waste contains at least one selected from the group consisting of water, solid content, short-chain fatty acid, triglyceride, long-chain fatty acid, vitamin E, and carotenoids. <7>In the step (a), the triglyceride decomposition rate is 90 to 100%, and the method for producing a long-chain fatty acid according to any one of <1> to <6>. <8>In the step (b), the removal rate of the short-chain fatty acid is 90 to 100%, and the method for producing a long-chain fatty acid according to any one of <1> to <7>. <9>The method for producing a long-chain fatty acid according to any one of <1> to <8>, wherein the short-chain fatty acid is at least one selected from the group consisting of butyric acid, propionic acid, isobutyric acid, isovaleric acid, valeric acid, caproic acid, lactic acid, and succinic acid. <10>The method for producing a long-chain fatty acid according to any one of <1> to <9>, wherein the long-chain fatty acid is at least one selected from the group consisting of lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. <11>A method for producing PHA, which includes a step of culturing a microorganism having PHA-producing ability using the long-chain fatty acid obtained by the method according to any one of <1> to <10>.

Examples

[0064] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0065] [Measurement and Evaluation Methods] The measurements and evaluations in the examples and comparative examples were carried out by the following methods.

[0066] (Triglyceride Decomposition Rate) Several mL of the reaction product after the enzymatic treatment in (enzymatic treatment, oil-water separation, hot water washing) described below were collected, held in a warm bath at 70 to 80 °C for several minutes to inactivate lipase. Next, only the oil phase was recovered from the mixture obtained after centrifugation and used as the oil phase sample. After dissolving the above oil phase sample in a mixed solution of isopropanol and hexane, gas chromatography was used to quantify glycerides. From the results obtained, the triglyceride decomposition rate was calculated by the following formula. Note that glycerides were the sum of monoglycerides, diglycerides, and triglycerides. Triglyceride decomposition rate [%] = 100 - (concentration of glycerides after reaction / concentration of glycerides before reaction).

[0067] (Removal rate of short-chain fatty acids) The removal rate of short-chain fatty acids was calculated by the following formula. Short-chain fatty acid removal rate [%] = (weight of recovered short-chain fatty acids / weight of short-chain fatty acids in crude vegetable oil) × 100 In the above formula, "crude vegetable oil" means "crude vegetable oil after enzymatic treatment in step (a) of this production method".

[0068] (Measurement of long-chain fatty acid recovery rate) The recovery rate of long-chain fatty acids (long-chain fatty acid recovery rate) obtained from waste containing plant-derived oil was calculated by the following formula. Long-chain fatty acid recovery rate [%] = weight of recovered long-chain fatty acids / total weight of fatty acids and triglycerides in crude vegetable oil × 100 In the above formula, "crude vegetable oil" means "crude vegetable oil before enzymatic treatment in step (a) of this production method".

[0069] (Measurement of long-chain fatty acid concentration in fatty acids) Using gas chromatography (manufactured by Shimadzu Corporation, GC-2030), the long-chain fatty acid concentration in the recovered fatty acids was measured. The long-chain fatty acid concentration was calculated by the following formula. Long-chain fatty acid concentration in fatty acids [%] = amount of recovered long-chain fatty acids / amount of recovered fatty acids × 100 (Colorimetric measurement) As the colority of the long-chain fatty acid, the Hazen unit color number described in JIS K 0071-1:2017 was adopted and measured using a Lovibond automatic colorimeter PFXi995P (manufactured by Tintometer).

[0070] (Quantitative analysis of vitamin E) The quantitative analysis of vitamin E (that is, tocopherol and tocotrienol) obtained from waste containing plant-derived oil was carried out by an external institution (Japan Food Analysis Center, Inc.) by the following method.

[0071] That is, samples of the examples and comparative examples were collected, and sodium chloride solution, pyrogallol, ethanol, and potassium hydroxide were added to saponify the samples. Next, sodium chloride solution and a mixed solution of hexane, 2-propanol, and ethyl acetate were added to the saponified samples, and shaking extraction was performed. After extraction, the above mixed solution was centrifuged, the upper layer was separated, and then the solvent was distilled off. A predetermined amount of hexane was added to the sample after solvent distillation, and it was quantified using high performance liquid chromatography and the sample was analyzed using a fluorescence spectrophotometer.

[0072] [Example 1] (Method for obtaining waste palm oil) The palm empty fruit bunch generated in the process of producing palm oil from palm fruits was treated with a pressing and dehydrating machine to obtain waste palm oil (hereinafter simply referred to as "waste palm oil") containing EFB crude oil (Empty Fruit Bunch crude oil), water, and solids.

[0073] (Decanter separation) The above waste palm oil was supplied to a three-phase separation decanter (manufactured by IHI Corporation) at 55 °C, 3500G, 1 to 2 m 3Decanter separation was carried out under the condition of / hr. By this operation, the above waste palm oil was separated at a ratio of EFB crude oil: water: solids = 4:94:2 by weight. Water and solids were removed from the separated waste palm oil to obtain EFB crude oil. It was confirmed by high-performance liquid chromatography, gas chromatography, and a Robivond automatic colorimeter that short-chain fatty acids, triglycerides, long-chain fatty acids, vitamin A, vitamin E, carotenoids, etc. were contained in the obtained EFB crude oil.

[0074] (Enzyme treatment·Oil-water separation·Hot water washing) The same weight of water was added to the above EFB crude oil and stirred at 40 °C for 15 minutes. Next, a solution of 0.03% by weight of triacylglycerol lipase EC 3.1.1.3 (trade name Lipase OF, manufactured by Meito Sangyo Co., Ltd.) was added to the EFB crude oil, stirred at 40 °C for 2 hours, and then left standing at 40 °C for 13 hours. By this operation, the triglycerides in the EFB crude oil were decomposed by the enzymatic action of lipase to produce fatty acids and glycerol. Next, the mixture of the EFB crude oil with decomposed triglycerides and water was heated to 70 °C to accelerate oil-water separation and inactivate the enzymatic action of lipase. After the above mixture was separated into an oil phase and an aqueous phase, the aqueous phase in which glycerol and inactivated lipase were dissolved was removed, and only the oil phase was recovered. Further, the same weight of water was added to the recovered oil phase, and it was washed with hot water by stirring at 70 °C for 30 minutes and left standing for 30 minutes. After the above mixture was separated into an oil phase and an aqueous phase, the aqueous phase was removed and the oil phase was recovered. The obtained oil phase was quantified using gas chromatography, and the triglyceride decomposition rate was calculated. The triglyceride decomposition rate of the above oil phase reached 98%, and the triglycerides were converted into fatty acids.

[0075] (Vacuum treatment) The above oil phase was held at 85 ± 5 °C and 13.3 kPa for 30 to 60 minutes to remove the remaining water in the oil phase.

[0076] (Degassing treatment) The above oil phase subjected to the depressurization treatment was preheated to 80°C. Next, the above oil phase was passed through a degasser with an internal temperature of 120°C and a pressure of 10 mbar to remove short-chain fatty acids and the like having a boiling point of 200°C or lower from the oil phase. Note that it was confirmed by quantification using gas chromatography that the removal rate of the removed short-chain fatty acids and the like was 97%.

[0077] (Short-path distillation) The above oil phase subjected to the degassing treatment was supplied to a short-path distillation apparatus (diameter 1.2 m, heat transfer area 0.1 m 2 , manufactured by UIC) at a rate of 10 kg / hr. The pressure inside the distillation apparatus was set to 50 Pa, and the rotational speed of the roller wiper was set to 100 rpm. Also, the temperature of the water used in the internal condenser was maintained at 70°C by a temperature control system, and the wall temperature of the distillation apparatus was set to 175°C. By this operation, the long-chain fatty acids dissolved in the oil phase evaporated from the wall surface of the distillation apparatus, then condensed on the surface of the internal condenser, and were discharged outside the distillation apparatus. The discharged long-chain fatty acids were recovered, and the recovery rate and chromaticity were measured. The recovery rate of the obtained long-chain fatty acids, the long-chain fatty acid concentration in the fatty acids, and the chromaticity are shown in Table 1.

[0078] 〔Example 2〕 Long-chain fatty acids were obtained by the same operation as in Example 1, except that the wall temperature of the short-path distillation apparatus was set to 188°C. The triglyceride decomposition rate in the enzymatic treatment step reached 98%, and the removal rate of short-chain fatty acids and the like during the degassing treatment was 97%. The recovery rate of the obtained long-chain fatty acids, the long-chain fatty acid concentration in the fatty acids, and the chromaticity are shown in Table 1.

[0079] 〔Example 3〕 Long-chain fatty acids were obtained by the same operation as in Example 1, except that the wall temperature of the short-path distillation apparatus was set to 193°C. The triglyceride decomposition rate in the enzymatic treatment step reached 98%, and the removal rate of short-chain fatty acids and the like during the degassing treatment was 97%. The recovery rate of the obtained long-chain fatty acids, the long-chain fatty acid concentration in the fatty acids, and the chromaticity are shown in Table 1.

[0080] 〔Example 4〕 The long-chain fatty acids were obtained by the same operation as in Example 1, except that the pressure in the short-path distiller was set to 10 Pa and the wall temperature was set to 170°C. The triglyceride decomposition rate in the enzymatic treatment step reached 98%, and the removal rate of short-chain fatty acids and the like during the degassing treatment was 97%. The recovery rate of the obtained long-chain fatty acids, the long-chain fatty acid concentration in the fatty acids, and the chromaticity are shown in Table 1.

[0081] [Example 5] The long-chain fatty acids were obtained by the same operation as in Example 4, except that the wall temperature of the short-path distiller was set to 165°C. The triglyceride decomposition rate in the enzymatic treatment step reached 98%, and the removal rate of short-chain fatty acids and the like during the degassing treatment was 97%. The recovery rate of the obtained long-chain fatty acids, the long-chain fatty acid concentration in the fatty acids, and the chromaticity are shown in Table 1.

[0082] [Example 6] The long-chain fatty acids were obtained by the same operation as in Example 4, except that the wall temperature of the short-path distiller was set to 160°C. The triglyceride decomposition rate in the enzymatic treatment step reached 98%, and the removal rate of short-chain fatty acids and the like during the degassing treatment was 97%. The recovery rate of the obtained long-chain fatty acids, the long-chain fatty acid concentration in the fatty acids, and the chromaticity are shown in Table 1.

[0083] [Comparative Example 1] The long-chain fatty acids were obtained by the same operation as in Example 1, except that enzymatic treatment, oil-water separation, and hot water washing were not performed. The recovery rate of the obtained long-chain fatty acids, the long-chain fatty acid concentration in the fatty acids, and the chromaticity are shown in Table 1.

[0084] [Comparative Example 2] The long-chain fatty acids were obtained by the same operation as in Example 1, except that the enzymatic treatment in step (a) and the removal of short-chain fatty acids in step (b) were not performed. The triglyceride decomposition rate was 0%, and the removal rate of short-chain fatty acids was 0%. The recovery rate of the obtained long-chain fatty acids, the long-chain fatty acid concentration in the fatty acids, and the chromaticity are shown in Table 1.

[0085] [Table 1] [Results] From Table 1, it was found that in the examples, long-chain fatty acids with a high recovery rate and a low chromaticity could be recovered as compared with the comparative examples. That is, it was found that by performing the enzyme treatment step in step (a) and the short-chain fatty acid removal step in step (b) before the long-chain fatty acid recovery step in the above step (c), long-chain fatty acids with high colorless transparency (low chromaticity) could be obtained at a high recovery rate.

Industrial Applicability

[0086] Since the present invention can produce long-chain fatty acids with a high recovery rate and a low chromaticity, it can be advantageously used in the production of long-chain fatty acids. Further, the long-chain fatty acids obtained by the present production method can be suitably used in food, bioculture, agriculture, fishery, forestry, horticulture, medicine, and other fields.

Claims

1. (a) A step of decomposing triglycerides in crude vegetable oil derived from waste containing plant-derived oil into fatty acids using an enzyme; (b) A step of removing short-chain fatty acids in the crude vegetable oil after the step (a) by distillation; and (c) A step of recovering long-chain fatty acids in the crude vegetable oil after the step (b) by short-path distillation, wherein the short-chain fatty acids are fatty acids having 8 or fewer carbon atoms, and the long-chain fatty acids are fatty acids having 9 or more carbon atoms. A method for producing long-chain fatty acids.

2. The chromaticity of the long-chain fatty acids is 700 or less, and the recovery rate of the long-chain fatty acids represented by the following formula (1) is 40% or more, wherein the chromaticity is the Hazen unit color number described in JIS K 0071-1:2017. The method for producing long-chain fatty acids according to Claim 1. Weight of long-chain fatty acids obtained in step (c) / Total weight of fatty acids and triglycerides in the crude vegetable oil in step (a) × 100... (1)

3. The concentration of long-chain fatty acids in the fatty acids represented by the following formula (2) is 99.0% or more. The method for producing long-chain fatty acids according to Claim 1 or 2. Amount of long-chain fatty acids obtained in step (c) / Amount of fatty acids obtained in step (c)... (2)

4. Before the step (a), the method for producing long-chain fatty acids according to any one of Claims 1 to 3, including the following step (a'): (a') A step of separating waste containing plant-derived oil into an oil phase, an aqueous phase, and a solid content phase, and removing the aqueous phase and the solid content phase to obtain crude vegetable oil.

5. In the step (c), the short-path distillation is performed (i) at an internal pressure of the apparatus of 5 to 30 Pa and a wall temperature of the apparatus of 150 to 180 °C, or (ii) at an internal pressure of the apparatus exceeding 30 Pa and 250 Pa or less and a wall temperature of the apparatus of 170 to 200 °C. The method for producing long-chain fatty acids according to any one of Claims 1 to 4.

6. The waste contains at least one selected from the group consisting of water, solid content, short-chain fatty acids, triglycerides, long-chain fatty acids, vitamin E, and carotenoids. The method for producing long-chain fatty acids according to any one of Claims 1 to 5.

7. In the step (a), the triglyceride decomposition rate is 90 to 100%. The method for producing long-chain fatty acids according to any one of Claims 1 to 6.

8. In the step (b), the removal rate of short-chain fatty acids is 90 to 100%. The method for producing long-chain fatty acids according to any one of Claims 1 to 7. **Claim 9** The method for producing a long-chain fatty acid according to any one of claims 1 to 8, wherein the short-chain fatty acid is at least one selected from the group consisting of butyric acid, propionic acid, isobutyric acid, isovaleric acid, valeric acid, caproic acid, lactic acid, and succinic acid. **Claim 10** The method for producing a long-chain fatty acid according to any one of claims 1 to 9, wherein the long-chain fatty acid is at least one selected from the group consisting of lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. **Claim 11** A method for producing polyhydroxyalkanoic acid, comprising a step of culturing a microorganism having the ability to produce polyhydroxyalkanoic acid using the long-chain fatty acid obtained by the method according to any one of claims 1 to 10.

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