Method for extracting lipids from microorganisms

Abstract

The present application relates to a method for extracting lipids from microorganisms, comprising the steps of: (a) preparing a microbial fermentation solution containing lipids; (b) fluidized-bed drying the microbial fermentation solution of step (a) so as to form microbial granules; and (c) press-extracting the microbial granules of step (b), wherein a solvent is not used during lipid extraction.

Description

Method for extracting lipids from microorganisms

[0001] The present application relates to a method for extracting lipids from microorganisms.

[0002]

[0003] Fat, along with carbohydrates and protein, is one of the three major nutrients and is found in most foods consumed by humans. The global population continues to grow, and demand for foods like meat and dairy products, which humans consume for nutritional purposes, is expected to increase accordingly. However, due to issues with current agricultural practices and the carbon footprint of meat consumption, there have been discussions on producing oil from microorganisms and using them as alternatives for environmentally sustainable purposes.

[0004] A method for obtaining microbial lipids by separating lipids produced from microbial cells and drying and extracting them is known, but since organic solvents such as n-hexane or isopropyl alcohol are required for lipid extraction, there is a problem that organic solvent residues may have a harmful effect on the human body.

[0005] Solvent-free extraction methods for extracting lipids from microorganisms include mechanical disruption, enzymatic treatment, and chemical treatment to lyse cells and then extract lipids. However, these methods require a separate extraction process after cell lysis, and emulsification by polar lipids makes lipid separation difficult. Furthermore, the multi-step process is complex and uneconomical.

[0006] The pressing extraction method is a method of extracting lipids from seeds such as sesame, perilla, and sunflower seeds. When using the pressing lipid extraction method, it is the most effective because the cell lysis and extraction methods can be shortened to one step, but the dry particles of the cell culture solution are very small, making it difficult to extract by pressing.

[0007]

[0008] The purpose of the present application is to provide a method for extracting lipids from microorganisms, comprising the steps of (a) preparing a microbial fermentation liquid containing lipids; (b) forming microbial granules by fluidized bed drying the microbial fermentation liquid of step (a); and (c) extracting the microbial granules of step (b) by compression.

[0009]

[0010] As one aspect for achieving the above object, the present application provides a method for extracting lipid from a microorganism, comprising the steps of (a) preparing a microbial fermentation liquid containing lipid; (b) forming microbial granules by fluidized bed drying the microbial fermentation liquid of step (a); and (c) extracting the microbial granules of step (b) by compression.

[0011]

[0012] The present application relates to an efficient method for extracting lipids from microorganisms without using a solvent. The method is a pressing extraction process that does not require enzyme treatment, high-temperature heat treatment, base treatment, organic solvent treatment, and cell wall destruction treatment, which are commonly used in microbial lipid extraction. As a result, the overall process steps are simple, and economical and environmentally friendly microbial oil can be produced.

[0013]

[0014] Figure 1 illustrates a process flow diagram of a method for extracting lipids from microorganisms according to the present application.

[0015]

[0016] This is explained in detail as follows. Meanwhile, each description and embodiment disclosed in this application can also be applied to each other description and embodiment. That is, all combinations of the various elements disclosed in this application fall within the scope of this application. Furthermore, the scope of this application is not limited by the specific descriptions described below. Furthermore, numerous papers and patent documents are referenced and cited throughout this specification. The disclosures of the cited papers and patent documents are incorporated into this specification in their entirety by reference to more clearly explain the level of the technical field to which this application belongs and the contents of this application.

[0017]

[0018] One aspect for achieving the above object provides a method for extracting lipids from microorganisms, comprising the steps of: (a) preparing a microbial fermentation liquid containing lipids; (b) forming microbial granules by fluidized bed drying the microbial fermentation liquid of step (a); and (c) extracting the microbial granules of step (b) by compression.

[0019] In the present application, the method is characterized by not using a solvent during lipid extraction, but is not limited thereto.

[0020]

[0021] The term "microorganism" in this application encompasses both wild-type microorganisms and microorganisms that have undergone natural or artificial genetic modification. The microorganism may be, but is not limited to, yeast, microalgae, bacteria, or mixtures thereof. The term "microorganism" may be used interchangeably with "strain."

[0022] The microorganism of the present application may be a lipid-containing microorganism. The term "lipid-containing microorganism" may be used interchangeably with "lipid-containing microorganism." The lipid-containing microorganism may be a microorganism that naturally contains lipids or a microorganism that has been genetically modified to contain lipids.

[0023] The microorganisms of the present application include yeasts such as Yarrowia lipolytica, Saccharomyces cerevisiae, Candida curvata, Lipomyces starkeyi, and Rhodococcus opacus; microalgae such as Thraustochytrium sp., Haematococcus pluvialis, Botryococcus braunii, and Schizochytrium sp.; And it may be at least one selected from the group consisting of bacteria such as Acinetobacter calcoaceticus, Rhodococcus opacus, and Bacillus alcalophilus. For example, the microorganism of the present application may be a microorganism of the genus Yarrowia, and specifically, may be Yarrowia lipolytica, but is not limited thereto.

[0024]

[0025] The term "lipid" in this application refers to biomolecules that are dissolved in nonpolar solvents among substances found in living organisms, and lipids include fatty acids, waxes, sterols, fat-soluble vitamins (e.g., vitamin A, vitamin D, vitamin E, vitamin K), monoglycerides, diglycerides, triglycerides, and phospholipids, and are classified into eight types: fatty acids, glycerolipids, glycerophospholipids, sphingolipids, glycolipids, polyketides, sterol lipids, and prenol lipids. The lipids may include, but are not limited to, unsaturated fatty acids and saturated fatty acids.

[0026]

[0027] In the method for extracting lipids from microorganisms of the present application, step (a) is a step for preparing a microbial fermentation liquid containing lipids.

[0028] The step of preparing a microbial fermentation solution can be accomplished by cultivating microorganisms in a medium.

[0029] The term "fermentation" in this application refers to the process of growing microorganisms under appropriately controlled environmental conditions, and refers to a process in which microorganisms use their enzymes to decompose organic matter, other than a putrefaction reaction. Fermentation and putrefaction reactions proceed through similar processes; however, if the decomposition results in the production of useful substances, it is called fermentation, whereas if it results in the production of foul-smelling or harmful substances, it is called putrefaction. In this context, the term "fermentation" may be used interchangeably with "microbial fermentation," "cultivation," and "microbial cultivation."

[0030] The term "fermentation solution" in the present application refers to a liquid medium in which a fermentation process has been completed by microorganisms, and the "fermentation solution" may be used interchangeably with "microbial fermentation solution", "culture solution", "microbial culture solution", and "biomass". Furthermore, the fermentation solution includes not only the fermented material itself, but also a culture medium of a strain in which a strain and a culture coexist, a fermented product obtained by filtering the strain from the culture medium, a fermented product obtained by sterilizing the strain from the culture medium and filtering it, an extract obtained by extracting the fermented product or a culture medium containing it, a diluted solution obtained by diluting the fermented product or its extract, a concentrate obtained by drying the fermented product or its extract, a lysate obtained by capturing and crushing the cells of the strain, and all kinds of materials including a fermented product generated from the strain.

[0031]

[0032] In the present application, the fermentation process can be conducted using appropriate media and culture conditions known in the art. This fermentation process can be easily adjusted and used by those skilled in the art depending on the selected strain. Specifically, the fermentation may be batch, continuous, and / or fed-batch, but is not limited thereto.

[0033] The microorganism of the present application can be fermented under aerobic conditions in a conventional medium containing appropriate carbon sources, nitrogen sources, phosphorus, inorganic compounds, amino acids and / or vitamins, while controlling temperature, pH, etc.

[0034] In the present application, the carbon source may include carbohydrates such as glucose, saccharose, lactose, fructose, sucrose, maltose, etc.; sugar alcohols such as mannitol, sorbitol, etc.; organic acids such as pyruvic acid, lactic acid, citric acid, etc.; amino acids such as glutamic acid, methionine, lysine, etc. In addition, natural organic nutrients such as starch hydrolysate, molasses, blackstrap molasses, rice winter, cassava, sugarcane bagasse, and corn steep liquor may be used, and specifically, carbohydrates such as glucose and sterilized pretreated molasses (i.e., molasses converted to reducing sugar) may be used, and other appropriate amounts of carbon sources may be used in various ways without limitation. These carbon sources may be used alone or in combination of two or more, but are not limited thereto.

[0035] The nitrogen source may include inorganic nitrogen sources such as ammonia, ammonium sulfate, ammonium chloride, ammonium acetate, ammonium phosphate, ammonium carbonate, ammonium nitrate, etc.; organic nitrogen sources such as amino acids such as glutamic acid, methionine, glutamine, etc.; peptone, NZ-amine, meat extract, yeast extract, malt extract, corn steep liquor, casein hydrolysate, fish or its decomposition product, defatted soybean cake or its decomposition product, etc. These nitrogen sources may be used alone or in combination of two or more, but are not limited thereto.

[0036] The above-mentioned components may include potassium phosphate monobasic, potassium phosphate dibasic, or their corresponding sodium-containing salts. Inorganic compounds may include sodium chloride, calcium chloride, iron chloride, magnesium sulfate, iron sulfate, manganese sulfate, calcium carbonate, etc. In addition, amino acids, vitamins, and / or suitable precursors may be included. These components or precursors may be added to the medium in batch or continuous manner, but are not limited thereto.

[0037] During the microbial fermentation of the present invention, compounds such as ammonium hydroxide, potassium hydroxide, ammonia, phosphoric acid, sulfuric acid, etc. can be added to the medium in an appropriate manner to adjust the pH of the medium. In addition, during the fermentation, an antifoaming agent such as fatty acid polyglycol ester can be used to suppress bubble formation. In addition, to maintain the aerobic state of the medium, oxygen or an oxygen-containing gas can be injected into the medium, or to maintain anaerobic and microaerobic states, nitrogen, hydrogen, or carbon dioxide gas can be injected without gas injection, but the present invention is not limited thereto.

[0038] Additionally, the culture medium may contain metal salts, such as magnesium sulfate or iron sulfate, necessary for growth. Finally, in addition to the above substances, essential growth substances, such as amino acids and vitamins, may be used. Appropriate precursors may also be used in the culture medium. The above-mentioned raw materials may be added to the culture during the fermentation process in a batch or continuous manner, but are not limited thereto.

[0039]

[0040] In the fermentation of the present application, the culture temperature can be maintained at 20°C to 35°C, specifically 25°C to 35°C, and the culture period can continue until the amount of useful substances produced is obtained, and the culture can be performed for about 10 hours to 160 hours, about 20 hours to 130 hours, about 24 hours to 120 hours, about 36 hours to 120 hours, about 48 hours to 120 hours, about 48 hours or more, or about 48 hours, about 72 hours, or about 120 hours, but is not limited thereto.

[0041]

[0042] In the present application, a step of membrane-filtering the microbial fermentation product prepared in step (a) may be additionally included. The membrane filtration may be performed for the purpose of separating and obtaining the microbial cells (concentrate) within the fermentation product from the liquid (filtrate).

[0043] In the present application, a step of washing the cell body (concentrate) after the membrane filtration step may be additionally included. This washing may be performed to remove impurities accompanying the cell body (concentrate). The washing step may be performed 1 to 3 times by adding water equal to the volume of the concentrate, but is not limited thereto.

[0044]

[0045] In the present application, a step of heating the microbial fermentation solution prepared in step (a) may be additionally included. This step is for inactivating microorganisms, and is a heating step for killing and / or sterilizing microorganisms or inactivating enzymes undesirable for lipid extraction at low or high temperatures. The heating temperature in the heating step may be 60°C to 120°C, and specifically 70°C to 100°C, but is not limited thereto.

[0046]

[0047] In the method for extracting lipids from microorganisms of the present application, step (b) is a step of forming microbial granules by fluidized bed drying the microbial fermentation liquid. This is a process for increasing the size of particles to be compressed and extracted, thereby enhancing the efficiency of lipid extraction.

[0048] The step of forming microbial granules by fluidized bed drying of the microbial fermentation solution of the present application may be performed simultaneously by a fluidized bed granule dryer, but is not limited thereto.

[0049] The term "dry" in this application refers to a physical state that is dehydrated or anhydrous, i.e., substantially free of liquid. The drying process in this application may be drum drying, fluidized bed drying, spray drying, or freeze drying, and more specifically, fluidized bed drying.

[0050] The term "fluidized bed drying" in the present application refers to a method of drying by blowing hot air from the bottom of a material layer filled on a perforated plate to move the material granules as if they were fluid, and a fluidized bed refers to a state in which the hot air and the material particles are mixed and actively move as if the liquid is boiling, but are not blown away by the hot air. The fluidized bed drying in the present application may be drying by a fluidized bed granulation dryer, or may be spray coating a microbial fermentation liquid by a bottom spray coating method, but is not limited thereto.

[0051] In the present application, the input flow rate of the fluidized bed granulation dryer may be 400 g / hr or more, and specifically, may be 400 to 1000 g / hr, 400 to 800 g / hr, 400 to 700 g / hr, 400 to 600 g / hr, 400 to 500 g / hr, or 450 to 550 g / hr, but is not limited thereto.

[0052] In the present application, the microbial granules may contain particles having a particle size of 0.5 mm or more in an amount of 80% or more, specifically, 85% or more, but are not limited thereto.

[0053] In the present application, the microbial granules may contain particles having a particle size of 1.0 mm or more in an amount of 40% or more, specifically, 50% or more, 60% or more, or 70% or more, but are not limited thereto.

[0054] In the present application, the moisture content of the microbial granules may be 7% or less, specifically 5% or less, more specifically 3% or less, and most specifically 2% or less, but is not limited thereto. By maintaining a low moisture content as described above, drying efficiency can be increased and contamination can be prevented.

[0055]

[0056] In the method for extracting lipids from microorganisms of the present application, step (c) is a step of compressing and extracting the microbial granules. This is an eco-friendly and efficient way to extract lipids from microorganisms, and is a simple process that eliminates the risk of residual solvents.

[0057] The term "pressing extraction" used in this application refers to a method of extracting oil by pressing. It is typically used to extract edible oil from oily raw materials such as olives or sesame seeds. Since the oil is extracted solely through pressure without the use of solvents, it has the advantage of being environmentally friendly and free of the risk of residual solvents. The pressing extraction used in this application may involve, but is not limited to, a method of extracting lipids by rotating a screw at high temperatures.

[0058] The compression extraction of the present application uses a milking machine, and the extraction temperature conditions may be 70°C to 200°C, specifically 90°C to 180°C, and more specifically 120°C to 150°C. The temperature conditions may be measured by measuring the temperature of the internal screw, but are not limited thereto.

[0059] In the present application, when extracting lipids by the above method, the lipid extraction rate may be 65% or more, specifically 68% or more, 68% to 90%, or 66.8% to 88%, but is not limited thereto.

[0060] In the present application, when extracting lipids using the above method, the acid value of the lipid extract may be 10 or less, specifically 9 or less, and more specifically 8 or less, but is not limited thereto.

[0061] The above method may include an additional purification process. The purification process may utilize any suitable method known in the art.

[0062]

[0063] The present application will be described in more detail below through examples. However, the following examples are merely preferred embodiments intended to illustrate the present application and are therefore not intended to limit the scope of the present application. Furthermore, technical details not described herein can be readily understood and implemented by those skilled in the technical field of the present application or similar fields.

[0064]

[0065] Example 1: Establishment of a lipid extraction process from microorganisms

[0066]

[0067] In order to establish a method for extracting lipids from microorganisms in an efficient and economical process, a lipid extraction method was developed by preparing a microbial fermentation solution → membrane filtration → inactivation → drying and granulation → solvent-free pressing.

[0068]

[0069] Example 1-1: Preparation process of microbial fermentation solution

[0070]

[0071] To obtain a microbial fermentation broth, a Yarrowia genus fermentation broth was prepared. Specifically, Yarrowia lipolitica CC08-0125 strain was cultured in a 5 L fermenter for 72 hours. For the purpose of seed culture, it was cultured for 30 hours under conditions of 30°C and 200 rpm in a 250 mL flask containing sterilized YLMM2 medium. The flask with the seed culture was dispensed and inoculated into a 5 L fermenter and cultured under conditions of sterilized YLMM2 medium and 30°C, 900 rpm, 1.0 vvm, and pH 7. The YLMM2 medium was prepared by dissolving 40 g / L of glucose, 1.7 g / L of yeast nitrogen base without amino acids and ammonium sulfate, 0.5 g / L of uracil, and 1.25 g / L of ammonium sulfate in 0.1 M sodium phosphate buffer.

[0072]

[0073] Example 1-2: Cell separation and washing process

[0074]

[0075] In order to separate and obtain the bacterial cells (concentrate) from the liquid (filtrate) in the fermentation broth prepared as in Example 1-1, a membrane filtration process was performed. Specifically, a microfiltration device from TAMI industries was used, and a membrane with a pore size of 0.14 μm was used, and the process was performed under the conditions of a filtration flux of 100-200 LMH, a concentration ratio of 2.0-3.0, and a temperature of 50°C. In order to further remove impurities accompanying the bacterial cells (concentrate), water of the same volume as the concentrate was added, and membrane filtration was performed twice.

[0076]

[0077] Example 1-3: Microbial inactivation process

[0078]

[0079] In order to kill and / or sterilize microorganisms in the cell (concentrate) manufactured as in Example 1-2, or to inactivate enzymes undesirable to lipids at low or high temperatures, a heating step was performed. Specifically, a shaking thermostatic bath from Jeiotech was used, and the temperature was treated at 80°C for 60 minutes.

[0080]

[0081] Example 1-4: Drying process and granulation process

[0082]

[0083] As in Example 1-3, the drying and granulation steps of the inactivated fungi (concentrate) were performed. In this step, the fungi (concentrate) was dried and granules of the dried product were simultaneously formed. The drying methods were drum drying, spray drying, freeze drying, and fluidized bed drying, respectively. Specifically, a drum dryer from Daesung Plant was used for the drum drying method, a spray dryer from Ain System was used for the spray drying method, a freeze dryer from Ilshin Biobase was used for the freeze drying method, and a fluidized bed granulation dryer from PTK was used for the fluidized bed drying method.

[0084]

[0085] Example 1-5: Lipid extraction process

[0086]

[0087] Lipids were extracted from the dried product prepared as in Example 1-4 using a solvent-free method. Among the solvent-free methods, lipids were extracted using a pressurized extraction method using an oil extractor manufactured by National Engineering, at extraction temperatures of 90°C, 120°C, 150°C, and 180°C.

[0088]

[0089] Comparative example: Solvent-based lipid extraction from microorganisms

[0090]

[0091] Lipids were extracted from the dried material prepared in Example 1-4 using a solvent method. Normal hexane (Daejung Chemical) was added in a volume 20 times the weight of the dried material, stirred for 1 hour, and the extract was filtered through a paper filter to obtain a liquid. The solvent was removed using an evaporator to obtain lipids.

[0092]

[0093] Example 2: Characteristic analysis method of manufactured dried product and lipid extract

[0094]

[0095] Example 2-1: Measurement of crude fat content

[0096]

[0097] To measure the lipid content in the dried product, ethanol and 4 M HCl were added to the dried powder and boiled at 80°C for 1 hour. After boiling, ethanol and ethyl ether were added, and centrifugation was performed to obtain the first supernatant. The lower layer was extracted twice with ethyl ether to obtain the second and third supernatants. The first to third supernatants were collected, placed on a plate, and dried in a dry oven for more than 1 hour.

[0098]

[0099] Crude fat content (%) = (dried weight - plate weight) / dry weight

[0100]

[0101] Example 2-2: Acid value measurement

[0102]

[0103] To estimate lipid degradation, the acid value of lipid extracts was measured. Acid value is a measure of the number of milligrams of KOH required to neutralize free fatty acids contained in lipids, indicating that fatty acids are not bound to glycerides. Lipids were dissolved in a mixture of ethanol and diethyl ether, titrated against a 0.1 M KOH solution, and the equivalence point was determined using a 1% phenolphthalein indicator.

[0104]

[0105] Acid value (mg / g KOH) = 5.61 × titer (titrant - blank titrant) / sample weight

[0106]

[0107] Example 2-3: Particle size measurement

[0108]

[0109] Samples less than 1500 μm were sieved and measured using a laser diffraction particle size analyzer, and samples greater than 1500 μm were sieved and measured.

[0110]

[0111] Example 2-4: Extraction rate calculation

[0112]

[0113] To confirm the efficiency of drying and extraction conditions, the extraction rate was calculated as follows based on the crude oil content in the dried material before extraction and the amount of lipid obtained after extraction.

[0114]

[0115] Extraction rate (%) = Extracted lipid / crude oil content in dry matter × 100

[0116]

[0117] Example 3: Investigation of the characteristics of lipid extraction process from microorganisms according to conditions.

[0118]

[0119] The extraction efficiency according to drying method, particle size, and extraction method was compared to secure optimal conditions.

[0120]

[0121] Example 3-1: Comparison of extraction rates according to drying method

[0122]

[0123] Drying methods were compared using drum drying, spray drying, freeze drying, and fluidized bed drying, and the extraction method was the same, compression extraction. Table 1 below shows the average particle size and extraction rate by drying method.

[0124]

[0125] Drying methodAverage particle size (μm)Extraction methodExtraction rate (%)Drum drying292Compression extraction28.5Spray drying2430Freeze drying25055.9Fluid bed drying78068.8

[0126] As a result, it was confirmed that the average particle size of the dried product and the lipid extraction rate differed depending on the drying method under the same compression extraction conditions as shown in Table 1 above. It was confirmed that the lipid extraction rate in the freeze-drying method and the fluidized bed drying method was approximately twice as high as that in other drying methods, indicating excellent lipid extraction efficiency.

[0127]

[0128] Example 3-2: Production of microbial lipid dried product using a fluidized bed granulator

[0129]

[0130] 3-2-1: Changes in granule size according to solid content of fermented microbial concentrate

[0131]

[0132] We examined whether particle size distribution varied depending on the solids content of the fermented microbial concentrate. To achieve granulation, the fermented concentrate was concentrated under reduced pressure to control the solids content. Table 2 below shows the granule size distribution according to the variation in solids content of the fermented microbial concentrate.

[0133]

[0134] 12345 Fermented concentrate input amount g 1500 1500 1500 1500 1500 Solid content g 187.5 225 262.5 277.5 300 Fat purity % 45 45 45 45 45 45 Fat content g 84.4 10 1.3 118.1 124.9 135.0 Granular condition Concentrate input Flow rate g / hr 500 500 500 500 500 Particle size distribution (μm) ≥ 2000% 3.4 2.2 3.4 3.8 3.3 1 500 ≤ X ≤ 2000% 33.5 3.8 37.9 34.5 38.1 1 000 ≤ X ≤ 1 500% 29.2 24.1 29.1 2 5 29.2 500 ≤ X ≤ 1 000% 18.8 19.4 16.5 15.5 15.8 1 00 ≤ X ≤ 500% 10.7 14.5 8.4 18.7 9.4 ≤ 100% 4.4 6 4.7 5 4.2 Total % 100 100 100 100 100

[0135] As a result, it was confirmed that there was no change in the overall granule particle size distribution depending on the difference in solid content of the fermented microbial concentrate as shown in Table 2 above.

[0136]

[0137] 3-2-2: Changes in granule particle size according to the injection rate of fermented microbial concentrate

[0138]

[0139] We examined whether particle size distribution varied depending on the flow rate of the fermented microbial concentrate granulated. Granulation was performed while maintaining the same amount of fermented concentrate and solids content, but sequentially increasing the flow rate. Table 3 below shows the particle size distribution of the granulated products according to the fermented concentrate injection rate.

[0140]

[0141] 12345 Fermented concentrate input amount g 1000 1000 1000 1000 1000 Solid content g 175 175 175 175 175 Fat purity % 45 45 45 45 45 45 Fat content g 78.8 78.8 78.8 78.8 Granular condition Concentrate input Flow rate g / hr 100 200 300 400 500 Particle size distribution (μm) ≥ 2000% 000 1.13.4 1500 ≤ X ≤ 2000% 008.5 19.6 37.9 1000 ≤ X ≤ 1500% 2.8 13.5 22.12 8.5 29.1500 ≤ X ≤ 1000% 28.5 25.7 30.9 31.116.5 100 ≤ X ≤ 500% 35.6 40.7 25.2 10.9 8.4 ≤ 100% 33.12 0.11 3.3 8.8 4.7 Total % 100 100 100 100 Average particle size μm 5 38.16 8 3.19 49.8 12 48.8 15 7 6.2

[0142] As a result, as shown in Table 3 above, as the input speed of the fermentation concentrate increased, the particle size distribution of 1000 μm or more increased, and when input was 500 g / hr, the particle size distribution of 1000 μm or more was the highest at 70.4%. Based on the above results, it was confirmed that the particle size can be controlled depending on the input flow rate of the fermentation concentrate.

[0143]

[0144] Example 3-3: Comparison of extraction rates by particle distribution

[0145]

[0146] Five particle distributions were selected to identify the particle size that showed the highest extraction efficiency under the same extraction method by separating by particle distribution. They were classified by particle size into less than 100 μm, 100 μm or more but less than 500 μm, 500 μm or more but less than 1000 μm, 1000 μm or more but less than 2000 μm, and 2000 μm or more but less than 3000 μm, and the extraction method was the same for all, pressing extraction. Table 4 below shows the difference in extraction rate according to particle distribution.

[0147]

[0148] Particle size (μm) Extraction method Extraction rate (%) <100 Pressing extraction 26 100~500 45 500~1000 69 1000~2000 84 2000~3000 88

[0149] As a result, it was confirmed that when the particle size was 500 μm or more under the same compression extraction method as in Table 4, the extraction rate was relatively appropriate at 69%, and when the particle size was 1000 μm or more, the extraction rate was 84% ​​to 88%, which was the best extraction rate.

[0150]

[0151] Example 3-4: Comparison of extraction rates by extraction temperature

[0152]

[0153] When extracting lipids using the compression extraction method, the lipid extraction rate according to the extraction temperature was confirmed (Table 5).

[0154]

[0155] Drying methodParticle size (μm)Extraction methodExtraction temperature (℃)Extraction rate (%)Fluidized bed drying1000~3000Compression extraction9084120881508818087

[0156] As a result, as shown in Table 5 above, when the internal screw temperature was set to 90°C to 180°C, all had excellent extraction rates, and in particular, when the temperature was set to 120°C to 150°C, the lipid extraction rate was 88%, which was the best extraction rate.

[0157]

[0158] Example 3-5: Comparison of changes in extraction yield and acid value according to changes in extraction and drying methods.

[0159]

[0160] Extracting lipids at high temperatures can lead to lipid oxidation. Therefore, to compare solventless and solvent-based extraction, the extraction yield and acid value were examined according to differences in drying and extraction methods. Table 6 below compares the extraction yield and acid value according to variations in extraction and drying methods.

[0161]

[0162] Extraction method Drying method Extraction rate (%) Acid value Compression extraction Drum drying 28.5 7.5 Spray drying 306.5 Freeze drying 55.9 3.3 Fluidized bed drying 68.8 7.7 Solvent extraction Drum drying 357.8 Spray drying 23.26.7 Freeze drying 323.1 Fluidized bed drying 23.5 7.1

[0163] As a result, as shown in Table 6 above, the acid value was the lowest when the freeze-drying method was used regardless of the extraction method. In addition, it was confirmed that the extraction rate varied depending on the extraction method even for dried products made with the same drying method. That is, in the case of dried products made with the same fluidized bed drying method, the extraction rate was only 23.5% when solvent extracted, but the extraction rate was 68.8% when compressed, confirming excellent extraction efficiency. However, although there was a difference in acid value depending on the drying method, the difference in acid value depending on the extraction method was not significant.

[0164]

[0165] In summary, in the case of the fluidized bed drying method among drying methods, the extraction efficiency of the dried product is good during the compression extraction, and as the input speed of the fermented microorganism concentrate increases, the granule particle size increases, and the larger the granule particle size, the higher the lipid extraction efficiency, so the lipid extract according to the drying method and extraction method according to the present application has excellent extraction efficiency and no difference in acid value, so that lipid can be extracted from microorganisms economically and efficiently.

[0166]

[0167] From the above description, those skilled in the art will understand that the present application can be implemented in other specific forms without altering its technical concept or essential characteristics. In this regard, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of this application should be interpreted as encompassing all changes or modifications derived from the meaning and scope of the following claims and their equivalents, rather than the detailed description above.

Claims

1. (a) A step of preparing a microbial fermentation solution containing lipid; (b) a step of forming microbial granules by fluidized bed drying the microbial fermentation solution of step (a); and (c) A method for extracting lipids from microorganisms, comprising a step of compressing and extracting the microbial granules of step (b).

2. A method according to claim 1, characterized in that no solvent is used during lipid extraction.

3. A method according to claim 1, wherein the microorganism is yeast, microalgae, bacteria or a mixture thereof.

4. A method according to claim 1, further comprising a step of filtering the microbial fermentation product in step (a).

5. A method according to claim 4, further comprising a step of washing the concentrate after the membrane filtration.

6. A method according to claim 1, further comprising a step of heating the microbial fermentation liquid in step (a).

7. A method according to claim 6, wherein the heating of the microbial fermentation liquid is performed at 60°C to 120°C.

8. A method according to claim 1, wherein the fluidized bed drying is performed using a fluidized bed granulation dryer.

9. A method according to claim 8, wherein, in the drying, the input flow rate of the microbial fermentation liquid is 400 g / hr or more.

10. A method according to claim 1, wherein the microbial granules of step (b) contain particles having a particle size of 0.5 mm or more at 80% or more.

11. A method according to claim 1, wherein the extraction temperature of step (c) is 70°C to 200°C.

12. In the first paragraph, the method for extracting lipids from the microorganism has at least one effect selected from the following i) and ii): i) Lipid extraction rate is 65% or more; and ⅱ) The acid value of the lipid extract is 10 or less.

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