METHOD FOR EXTRACTING OIL FROM MICROBIAL BIOMASS

Abstract

METHOD FOR EXTRACTING OIL FROM MICROBIAL BIOMASS ABSTRACT The current invention relates to a method for extracting oil from a microbial biomass comprising the steps of: mechanically lysing a microbial biomass, thereby obtaining a fat-in-water emulsion; churning the fat-in-water emulsion, thereby obtaining a water-in-fat emulsion and an aqueous phase; and centrifuging the water-in-fat emulsion, thereby obtaining a microbial 0” containing fraction.

Description

FIELD OF THE INVENTION The present invention relates to a . BACKGROUND The extraction of oil from microbial biomass, such as yeast, presents several challenges. Traditional methods typically involve the use of organic solvents, which can be both costly and environmentally harmful. These methods often require the drying of biomass to remove water, as the presence of water inhibits solvent extraction. The drying process itself is energy-intensive, adding to the overall cost and environmental impact. Furthermore, the use of solvents necessitates subsequent distillation and renewal processes, further increasing energy consumption and operational costs. Additionally, prior to drying, a cell disruption step is usually applied to enhance oil migration from the biomass into the solvent. This disruption is commonly achieved through enzymatic treatment, bead milling, ultrasound, or homogenization, all of which can be complex and require significant energy input. Another significant drawback of these traditional methods is the potential for heat-induced deterioration of the oil, which can compromise its quality. Finally, the remaining cell fragments after oil extraction are often dry, complicating further processing for the production of valuable ingredients. These issues highlight the need for a more efficient, environmentally friendly, and cost-effective . The present invention aims to resolve at least some of the problems and disadvantages mentioned above. SUMMARY OF THE INVENTION The present invention and embodiments thereof serve to provide a solution to one or more of above-mentioned disadvantages. To this end, the present invention relates to a method for extracting oil from a microbial biomass according to claim 1. Particularly, the invention provides a m2ethod for extracting oil from a microbial biomass comprising the steps lysing a microbial biomass, thereby obtaining a fat-in- water emulsion, churning the fat-in-water emulsion, thereby obtaining a water-in- fat emulsion and an aqueous phase, and centrifuging at least the water-in-fat emulsion, thereby obtaining a microbial oil containing fraction. Preferred embodiments of the device are shown in any of the claims 2 to 18. The provided method offers significant benefits primarily due to its low energy requirements. The absence of a need for water evaporation stands out as an advantage. Typically, processes that involve water evaporation consume a substantial amount of energy to convert water from liquid to vapor. By eliminating this phase, the overall energy consumption is markedly reduced. This characteristic not only enhances the efficiency of the process but also contributes to its sustainability. Additionally, this method is environmentally friendlier as it avoids the use of solvents. In conventional processes, solvents are often essential for extracting specific substances, but they pose environmental risks and require additional energy for distillation and renewal. By eschewing solvents, this technique not only reduces the potential for environmental harm but also curtails the energy expended in solvent recovery. Furthermore, the quality of the oil produced is preserved since it does not need to be heated to high temperatures, which can lead to heat-induced deterioration. This aspect ensures that the oil retains more of its natural qualities and efficacy. Lastly, the process leaves behind cell fragments in a wet state, which is advantageous for subsequent stages that convert these fragments into valuable ingredients. This moisture content is critical as it facilitates further processing without the need for rehydration, streamlining the production cycle and enhancing the feasibility of extracting additional valuable compounds from the biomass. DETAILED DESCRIPTION OF THE INVENTION The present invention concerns a . Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better3appreciate the teaching of the present invention. As used herein, the following terms have the following meanings: The term "churning" refers to the process of turbulent agitating of a liquid under cool conditions, during which air is beaten into the liquid to promote the coalescence of semi-solid fat bodies. This process is typically carried out in specialized equipment known as a churn, which can be either a batch churn or a continuous churn. Each type of churn is essentially a cylindrical container with a central axis that agitates the fluid. Churning is known in the field of butter making, wherein cream is agitated under controlled conditions to separate the butterfat from the buttermilk. The term lysing biomass refers to the process of breaking down biological material, such as cells, to release their internal components. The expression "mechanical lysis" refers to the process of breaking down microbial cells or through physical means to release their internal contents, including lipids. The term "fat-in-water emulsion" is synonym to oil-in-water emulsion and refers to a mixture where fat droplets are dispersed within a continuous water phase. The term "water-in-fat emulsion" is synonym to water-in-oil emulsion and refers to a mixture where water droplets are dispersed within a continuous fat phase. Butter is an example of a water-in-fat emulsion. A water-in-fat emulsion preferably has an oil content of at least 50 wt.%. The term "aqueous phase" refers to the water-based portion of a system in which water is the primary liquid. An aqueous phase can be characterized by a water content of at least 50 wt.%, or even at least 60, 70, 80 or 90 wt.%. The expression oleaginous as used herein refers to material, e.g., a microorganism, which contains a significant component of oils, or which is itself substantial composed of oil. An oleaginous microorganism can be one that is naturally occurring or synthetically engineered to generate a significant proportion of oil. The expression oleaginous yeast as used herein refers to a collection of yeast species that can accumulate a high proportion of their biomass as lipids (namely greater than 20% of dry cell mass). An o|:aginous yeast can be one that is naturally occurring or synthetically engineered to generate a significant proportion of oil. For the purposes of this disclosure microbial oil and microbial fat refer to microbial lipids produced by the microbial biomass, preferably the oleaginous microbial biomass. The expression "solid fat content" (SFC) refers to the proportion of fat that remains solid at a specific temperature. It is preferably measured using Nuclear Magnetic Resonance (NMR) spectroscopy, a technique outlined in the ISO 8292:2008 standard, which provides a rapid and non-destructive means of quantifying the solid and liquid phases of fats. A, an, and the as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, a compartment refers to one or more than one compartment. Comprise, comprising, and comprises and comprised of as used herein are synonymous with include, including, includes or contain, containing, contains and are inclusive or open-ended terms that specifies the presence of what follows e.g. component and do not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein. Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order, unless specified. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein. The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range, as well as the recited endpoints. The expression % by weight, weight percent, %wt. or wt.%, here and throughout the description unless otherwise defined, refers to the relative weight of the respective component based on the overall weight of the formulation. The expression % by volume, volumî percent, %vol or vol.%, here and throughout the description unless otherwise defined, refers to the relative volume of the respective component based on the overall volume. Whereas the terms one or more or at least one, such as one or more or at least one member(s) of a group of members, is clear per se, by means of further exemplification, the term encompasses inter a / ia a reference to any one of said members, or to any two or more of said members, such as, e.g., any 23, 24, 25, 26 or 27 etc. of said members, and up to all said members. Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, definitions for the terms used in the description are included to better appreciate the teaching of the present invention. The terms or definitions used herein are provided solely to aid in the understanding of the invention. Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at leastone embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination. In a first aspect, the invention relates to a method for extracting oil from a microbial biomass. In a preferred embodiment, the method comprises the steps of: i. lysing a microbial biomass, thereby obtaining a fat-in-water emulsion, ii. churning the fat-in-water emulsion, thereby obtaining a water-in-fat emulsion and an aqueous phase, and iii. centrifuging the water-in-fat eÎnulsion, thereby obtaining a microbial oil containing fraction. It has been found that oil can be extracted from microbial biomass by using a churning step after lysing. In the method of the invention, oil is extracted from microbial biomass by using disrupting the cells to form a coarse fat-in-water emulsion. The fat-in-water emulsion is churned thereby inversing the emulsion to obtain a water-in-fat emulsion and an aqueous phase. Churning is traditionally used in the dairy industry for making butter. During churning, partially solid oil droplets are agitated with shear and air, which causes the partially solid oil droplets to coalesce and grow. Eventually, the partially solid oil body engulfs all fat in the medium and separates into a water-in-fat emulsion (butter) and an aqueous phase (buttermilk). With coarse fat-in-water emulsion, an emulsion having a mean particle size between 1 and 100 um, preferably between 5 and 50 pm, is meant. The lysing is preferably mechanical lysing. Mechanical involves physically breaking open the cells in the biomass. This method is often preferred for its simplicity and effectiveness, and it can be especially useful when dealing with large volumes of biomass or when chemical and enzymatic methods might affect the integrity of the extracted molecules. Mechanical lysing is advantageous, because autolysis, enzymatic lysis or chemical lysis have been proven to not efficiently achieve an wat- in-water emulsion needed for churning. In a preferred embodiment, the method comprises the steps of: i. mechanically lysing a microbial biomass, thereby obtaining a fat-in-water emulsion, ii. churning the fat-in-water emulsion, thereby obtaining a water-in-fat emulsion and an aqueous phase, and iii. centrifuging the water-in-fat emulsion, thereby obtaining a microbial oil containing fraction. In an embodiment the churning is carried out at a temperature where the solid fat content of the fat-in-water emulsion is between 0 and 70 wt.%, preferably between 10 and 60 wt.%, more preferably between 20 and 50 wt.%, even more preferably between 20 and 40 wt.%, or even between 25 and 35 wt.%. The solid fat content is preferably measured according to ISO 8292:2008. It has been found that a solid content (SFC) between 20-50 wt.% is advantageous because it directly influences the efficiency and quality of the churning process. This SFC range ensures that the cream has enough solid fats to facilitate the aggregation and coalescence of fat globules during churning, which is crucial for forming butter granules. A lower SFC might not provide sufficient fat aggregation, leading to a longer churning time and potentially softer butter. It is noted that a higher solid fat content is possible but that this increases the churning time. A far higher SFC could result in too rapid aggregation, making the butter excessively hard and difficult to process. Thus, maintaining an SFC within this range helps achieve a balance, ensuring the water-in-fat emulsion has the right texture and firmness after churning, while also optimizing the churning process itself for time and energy efficiency. In an embodiment, the fat-in-water emulsion has a dry matter content of between 5 and 35 wt.%, preferably between 10 and 30 wt.%, even more preferably between 15 and 25 wt.%. In another or further embodiment, the fat-in-water emulsion can undergo an intermediate centrifugation prior to churning. In a further embodiment, the centrifuged fat-in-water emulsion has a dry matter content of at least 20 wt.%, preferably at least 25 wt.%, more preferably at least 30 wt.%, even more preferably at least 35 wt.%, even more preferably at least 40 wt.%, or even more preferably at least 45 wt.%. In another or further embodiment, the centrifuged fat-in-water emulsion has a dry matter content of between 20 and 70 wt.%, preferably between 25 and 70 wt.%, more preferably between 30 and 70 wt.%, even more preferably between 35 and 65 wt.%, even more preferably between 40 and 60 wt.%, or even more preferably between 45 and 55 wt.%. In an embodiment the churning is carried out at a temperature of between 0 and 20°C, preferably between 5 and 20°C, more preferably between 5 and 15°C, or even between 8 and 12°C. In an embodiment the water-in-fat emulsion obtained after churning has a fat content of at least 50 wt.%, more preferably at least 55 wt.%, even more preferably at least 60 wt.%, even more preferably at least 65 wt.%, even more preferably at least 70 wt.%. In another or further embodiment the wat8er-in-fat emulsion obtained after churning has a fat content of at most 90 wt.%, more preferably at most 85 wt.%, even more preferably at most 80 wt.%. In another or further embodiment the water-in-fat emulsion obtained after churning has a fat content of at between 50 and 90 wt.%, more preferably between 55 wt.% and 90 wt.%, even more preferably between 60 and 90 wt.%, even more preferably between 65 and 85 wt.%, even more preferably between 70 and 85 wt.%. In an embodiment, the water-in-fat emulsion has a dry matter content of at least 50 wt.%, more preferably at least 55 wt.%, even more preferably at least 60 wt.%, even more preferably at least 65 wt.%, even more preferably at least 70 wt.%, even more preferably at least 75 wt.%. In another or further embodiment, the water-in- fat emulsion has a dry matter content of between 50 and 95 wt.%, preferably between 55 and 95 wt.%, even more preferably between 60 and 95 wt.%, even more preferably between 65 and 95 wt.%, even more preferably between 70 and 95 wt.%, even more preferably between 75 and 95 wt.%, or even between 75 and 90 wt.%. In another or further embodiment the aqueous phase obtained after churning has a fat content of at most 5 wt.%, more preferably at most 2 wt.%, even more preferably at most 1 wt.%, even more preferably at most 0.5 wt.%, even more preferably at most 0.1 wt.%. During churning the fat-in-water emulsion is agitated under cool conditions, during which air is beaten into the liquid to promote coalescence of semi-solid fat bodies. Churning can be carried out in a churn, which can be a batch churn or a continuous churn. In both cases, the churn is preferably a cylindrical container with a central axis which agitates the fluid. In an embodiment, the churn is filled with fat-in-water emulsion for at most 70 vol.%, preferably at most 65 vol.%, more preferably at most 60 vol.%, even more preferably at most 55 vol.%, and most preferably at most 50 vol.%. The maximum filing percentage will allow sufficient air to be included during churning. In an embodiment, the churning is carrieîl out with an agitating speed of between 100 and 200 rpm, preferably between 120 and 180 rpm, more preferably between 130 and 170 rpm, even more preferably between 140 and 160 rpm. The water-in-fat emulsion and the aqueous phase obtained after churning can be separated before centrifuging or can be centrifuged together. The mechanical lysing is preferably performed using high-pressure homogenization, grinding or bead milling, preferably high-pressure homogenization or bead milling. High-pressure homogenization subjects the cell suspension to (very) high pressure, forcing it through a narrow space. This results in the rapid acceleration and deceleration of cells, causing them to rupture. The high-pressure homogenization is preferably conducted at a pressure of at least 300 bar, preferably at least 500 bar. In another or further embodiment the high-pressure homogenization is conducted at a pressure of between 500 and 5000 bar, preferably between 500 and 3000 bar. Bead beating involves agitating the microbial cells with small beads, typically made of glass, ceramic, or steel. This is done in a shaking or vortexing apparatus that physically disrupts the cells. The bead milling is preferably carried out with beads having a diameter between 100 um and 10 mm. Grinding with a mortar and pestle, particularly when cells are frozen with liquid nitrogen, is a manual but effective method to disrupt tough cell walls. The fat-in-water emulsion can be stored at a temperature between 0 and 99°C for a duration between 1 minute and 5 days before churning. The centrifugation step allows the remaining cell debris to settle after, the water of the water-in-fat emulsion to sediment & coalesce into a water phase, and the fat / oil to cream to the top and form a continuous oil containing fraction. The centrifugation will thus yield three phases. An oil containing fraction, the top phase, an aqueous middle phase which may contain some salts, sugars and soluble peptides, and a heavy solid phase containing cell fragments and denatured proteins. The oil containing fraction can be collected after centrifugation. Collecting the oil containing fraction can be done using several methods, such as decanting; pipetting or syringing: siphoning; or industrial autloenated separation equipment designed to continuously or semi-continuously remove the oil layer. These might use mechanical skimmers or programmed pumps that adjust based on the interface level detected by sensors. In an embodiment, the oil-containing fraction has a dry matter content of at least 70 wt.%, more preferably at least 75 wt.%, even more preferably at least 80 wt.%, even more preferably at least 85 wt.%, even more preferably at least 90 wt.%, even more preferably at least 95 wt.%, or even at least 99 wt.%. In an embodiment a heating step is carried out between the churning step and the centrifuging step. In this embodiment, at least the water-in-fat emulsion obtained after churning is heated to a temperature wherein said water-in-fat emulsion liquifies, thereby obtaining an oil-rich liquid phase, and the oil-rich liquid phase is centrifuged, thereby obtaining a microbial oil containing fraction. In a further embodiment the method comprises the steps of: i. mechanically lysing a microbial biomass, thereby obtaining a fat-in-water emulsion, ii. churning the fat-in-water emulsion, thereby obtaining a water-in-fat emulsion and an aqueous phase, iii. heating at least the water-in-fat emulsion to a temperature wherein said water-in-fat emulsion liquifies, thereby obtaining an oil-rich liquid phase, and iv. centrifuging the oil-rich liquid phase, thereby obtaining a microbial oil containing fraction. Heating the water-in-fat emulsion will result in an even better and more efficient separation process. The water-in-fat emulsion is preferably heated to a temperature of at least 60°C, more preferably at least 65°C, even more preferably at least 70°C. In another or further embodiment the water-in-fat emulsion is preferably heated to a temperature of between 20 and 99°C, preferably between 40 and 99°C, more preferably between 60 and 99°C, more preferably between 65 and 90°C, even more preferably between 70 and 80°C. Heating the water-in-fat emulsion to 70°C causes denaturation of proteins and liquifying of the oil. The centrifugation process allows the denatured proteins (alongside remaining cell debris) to settle, the water of the water-in-fat emulsion to sediment& coalesce into a water phase, and the fat / oil to cream to the top and form a continuous oil containing fraction. The water-in-fat emulsion and the aqueous phase obtained after churning can be separated before heating or can be heated and centrifuged together. In an embodiment, the method does not comprise the step of extracting by organic solvents, which the not only reduces the potential for environmental harm but also curtails the energy expended in solvent recovery. In an embodiment, the method does not comprise a drying step, which also only reduces the potential for environmental harm but also curtails the energy expended in solvent recovery. In an embodiment the microbial biomass comprises between 20 and 80 wt.% oil on a dry matter basis, preferably between 20 and 70 wt.%, more preferably between 30 and 70 wt.%, even more preferably between 40 and 70 wt.%, or even more preferably between 50 and 70 wt.% The particles in the microbial biomass have a D90 of between 0.5 and 50 um, preferably between 1 and 25 pm, more preferably between 1 and 10 um. The D90 is preferably measured according to ISO 13320:2020. The microbial biomass is preferably an oleaginous microbial biomass, which means it comprises preferably oleaginous microorganisms, such as bacteria, algae, yeast, or fungi. The microbial biomass is preferably a fermented microbial biomass. During the fermentation stage, the cell density and the microbial oil in the cell suspension will increase due to microbial growth. At a certain point, the microbial cell will have exhausted one or more nutrients required for further microbial growth and oil production. At such point, the oil may not further increase in the cell suspension and the oil may be extracted according to an embodiment of the method described herein. Hence, in some embodiments, the microbial biomass has a cell density selected from the range of 107 10ll celllsîml, such as from the range of 108 1010 cells / ml. The use of oleaginous microorganisms for oil production has many advantages over traditional oil harvesting methods, e.g., palm oil harvesting from palm plants. For example, microbial fermentation (1) does not compete with food production in terms of land utilization; (2) can be carried out in conventional microbial bioreactors; (3) has rapid growth rates; (4) is unaffected or minimally affected by space, light, or climate variations; (5) can utilize waste products as feedstock; (6) is readily scalable; and (7) is amenable to bioengineering for the enrichment of desired fatty acids or oil compositions. Oleaginous yeast in particular are robust, viable over multiple generations, and versatile in nutrient utilization. They also have the potential to accumulate intracellular lipid content up to greater than 70% of their dry biomass. The microbial biomass comprises preferably an oleaginous yeast. In some embodiments, the yeast may be in haploid or diploid forms. The yeasts may be capable of undergoing fermentation under anaerobic conditions, aerobic conditions, or both anaerobic and aerobic conditions. A variety of species of oleaginous yeast that produce suitable oils and / or lipids can be used to extract oil in accordance with the present disclosure. In some embodiments, the oleaginous yeast in the microbial biomass naturally produces high (20%, 25%, 50% or 75% of dry cell weight or higher) levels of suitable oils and / or lipids. In some embodiments, the oleaginous yeast comprises cells that are capable of producing at least 20%, 25%, 50% or 75% or more oil by dry weight. Suitable species of oleaginous yeast for extracting microbial oil according to the of the present disclosure include, but are not limited to Candida apico / a, Candida sp., Cryptococcus albidus. Cryptococcus curvatus, Cryptococcus terricolus, Cutaneotrichosporon oleaginosus, Debaromyces hansenii, Endomycopsis vernalis, Geotrichum carabidarum, Geotrichum cucujoidarum, Geotrichum histeridarum, Geotrichum silvico / a, Geotrichum vulgare, Hyphopichia burtonii, Lipomyces lipofer, Lipomyces orenta / is, Lipomyces starkeyi, Lipomyces tetrasporous, Pichia mexicana, Rhodosporidium sphaerocarpum, Rhodosporidium toruoides Rhodotoru / a aurantiaca, Rhodotorula dairenensis, Rhodotoru / a difuens, Rhodotoru / a glutinus, Rhodotoru / a glutinis var. glutinis, Rhodotorula gracilis, Rhodotorula graminis Rhodotorula minuta, Rhodotorula muci / aginosa, Rhodotorula muci / aginosa, Rhodotorula terpenoid / is, Rhodotoru / a toru / oides, Sporobo / omyces alborubescens, Starmere / la bomb / cola, Toru / aspora delbruekii, Toru / aspora 13prelroriensis, Trichosporon behrend, Trichosporon brassicas, Trichosporon domesticum, Trichosporon laibachii, Trichosporon loubieri, Trichosporon loubieri, Trichosporon montevideense, Trichosporon pullulans, Trichosporon Sp., Wickerhamomyces, Yarrowia lipolytica, and Zygoascus meyerae. In an embodiment, said yeast is from the Cutaneotrichosporon genus. Said Cutaneotrichosporon yeast is preferably Cutaneotrichosporon oleaginosus. Cutaneotrichosporon oleaginosus may be capable of growing and producing yeast oil at (relatively) low temperatures. Further, Cutaneotrichosporon oleaginosus may provide particularly high yeast oil yields and / or yeast oil titers compared to other species of yeast. Hence, Cutaneotrichosporon oleaginosus is particularly appropriate to provide a microbial oil. In a particularly preferred embodiment said microbial biomass comprises an oleaginous yeast, wherein said oleaginous yeast is Cutaneotrichosporon oleaginosus. In a particularly preferred embodiment the method comprises the steps of: i. mechanically lysing a microbial biomass, thereby obtaining a fat-in-water emulsion, wherein the microbial biomass comprises a yeast, preferably an oleaginous yeast, ii. churning the fat-in-water emulsion, thereby obtaining a water-in-fat emulsion and an aqueous phase, iii. optionally, heating at least the water-in-fat emulsion to a temperature wherein said water-in-fat emulsion liquifies, thereby obtaining an oil-rich liquid phase, and iv. centrifuging the water-in-fat emulsion or the oil-rich liquid phase, thereby obtaining a microbial oil containing fraction. In an embodiment, the oil containing fraction has an oil content of at least 85 wt.%, preferably at least 90 wt.%, more preferably at least 95 wt.% oil, and with the most preference at least 98 wt.% or even at least 99 wt.%. The oil containing fraction preferably comprises impurities in an amount of at most 10 wt.%, preferably at most 5 wt.%, and with the most preference at most 2 wt.% or 1 wt.%, or even at most 0.5 wt.%. Examples of possible impurities present in the oil containing fraction are moisture, waxes, or vitamins. The obtained oil containing fraction prefej'ably has a solid fat content at 20°C of between 5 and 80% by weight, preferably between 10 and 80% by weight, more preferably between 15 and 80% by weight, more preferably between 20 and 80% by weight, even more preferably between 25 and 80% by weight, even more preferably between 30 and 80% by weight. In an embodiment, said oil containing fraction has a solid fat content at 20°C of between 5 and 80% by weight, preferably between 5 and 70% by weight, more preferably between 5 and 60% by weight, even more preferably between 5 and 50% by weight, even more preferably between 5 and 40% by weight, even more preferably between 5 and 30% by weight. In an embodiment, said oil containing fraction has a solid fat content at 20°C of between 5 and 30% by weight, preferably between 5 and 25% by weight, more preferably between 5 and 20% by weight, even more preferably between 10 and 20% by weight. In an embodiment, said oil containing fraction has a solid fat content at 20°C of between 5 and 80% by weight, preferably between 10 and 70% by weight, more preferably between 15 and 60% by weight, even more preferably between 20 and 50% by weight, even more preferably between 25 and 40% by weight. In another or further embodiment, said oil containing fraction has a solid fat content at 20°C of at least5% by weight, preferably at least 10% by weight, more preferably at least 15% by weight. In an embodiment, said oil containing fraction has a solid fat content at 10°C of at least 25% by weight, preferably at least 30% by weight, more preferably at least 35% by weight. In an embodiment, said oil containing fraction has a solid fat content at 10°C of between 25 and 90% by weight, preferably between 30 and 85% by weight, preferably between 35 and 85% by weight. In an embodiment, said oil containing fraction has a solid fat content at 10°C of between 25 and 60% by weight, preferably between 25 and 50% by weight, preferably between 30 and 50% by weight, preferably between 30 and 45% by weight, more preferably between 35 and 45% by weight. In an embodiment, said oil containing fraction has a solid fat content at 25°C of at most 5% by weight, preferably at most 1% by weight, preferably at most 0.5% by weight, preferably at most 0.1% by weight. In an embodiment, said oil containing fraction has a solid fat content at 30°C of at most 5% by weight, preferably at most 1% by weight, preferably at most 0.5% by weight, preferably at most 0.1% by weight, more preferably at most 0.01% by weight. Churning has been proven to efficiently work on oils with a high melting point. The technique is traditionally used in the dairy industry for making butter. During churning, the partially solid oil droplets are agitated with shear and air, which causes the partially solid oil droplets to coalesce and grow. Eventually, the partially solid oil body engulfs all fat in the medium and separates into a water-in-fat emulsion (butter) and an aqueous phase (buttermilk). The extracted oil containing fraction can be used for producing derivatives, such as triglycerides, diglycerides, monoglycerides, free fatty acids, fatty acid salts, glycerin, fatty esters, fatty alcohols, fatty amines, fatty acid methyl esters, amide carboxylates, FOH ethoxylates, FOH sulfates, amine oxides, betaines, quats, sophorolipids, ether sulfates, or a combination thereof. These derivatives can for example subsequently be used in food products, feed products, pet feed, personal care products, home care products, fuels, pharmaceuticals, or a combination thereof. In an embodiment, the extracted oil containing fraction is used in food products, feed products, pet feed, personal care products, home care products, fuels, pharmaceuticals, or a combination thereof. More specifically, the extracted oil containing fraction can be used in bakery products; confectionery items; dairy alternatives; frying oils; spreads and margarines; salad dressings; nutraceuticals; animal feed; pet food; personal care products; pharmaceuticals; biofuels; industrial lubricants; surfactants; soaps and detergents. The extracted oil containing fraction may serve as palm oil alternatives and may be processed and / or derivatized by any number of means known in the art. The extracted oil containing fraction and / or derivatives thereof may be used in a variety of downstream products of interest, such as food products, feed products, pet feed, personal care products, home care 1p6roducts, fuels, pharmaceuticals, or a combination thereof. The invention is further described by the following non-limiting examples which further illustrate the invention, and are not intended to, nor should they be interpreted to, limit the scope of the invention. EXAMPLES Example 1 After fermentation of an oleaginous yeast, the biomass is subjected to high-pressure homogenization at two times 2700 bar. The effect of this homogenization on the yeast cells is shown in figures 1 and 2, wherein figure 1 shows the biomass prior to homogenization, and figure 2 shows the cell disruption after homogenization. In-between centrifugation of the disrupted biomass shows that a clear emulsion layer appears as a top layer C when the cells are disrupted. The disruption and centrifugation greatly concentrated the percentage of fat per volume. The effect of the disruption is shown in figures 3 and 4, wherein figure 3 shows the undisrupted centrifuged biomass A, and figure 4 shows the cell disrupted centrifuged biomass B Figure 5 shows the particle size distribution of the emulsion obtained after centrifuging the homogenized biomass. The particle size is around 10 um, which is a quite coarse emulsion. Churning, carried out in a lab-scale churn set-up for 20 minutes at 150 rpm churning speed with a horizontal stirrer, allowed the formation of a water-in-fat emulsion and an aqueous phase. This is similar to the churning of cream after which butter and buttermilk are obtained. The water-in-fat emulsion (with a clear butter-like structure) is shown in figure 6. After melting the water-in-fat emulsion by heating it to 70°C, the heated water-in- fat emulsion is centrifuged to separate the proteins and the water from the oil. The microbial oil, which is clear and colorless, is subsequently isolated. The oil is clear and colorless as a consequence of the mild wet processing. The obtained oil is shown in figure 7. The percentage of dry matter of the interanediate products at different stages of the process according to an embodiment of the invention are shown in table 1 Table 1 _ The present invention is in no way limited to the embodiments described in the examples and / or shown in the figures. On the contrary, methods according to the present invention may be realized in many different ways without departing from the scope of the invention. The invention may thus be described according to the following embodiments: 1. A method for extracting oil from a microbial biomass comprising the steps of: i. mechanically lysing a microbial biomass, thereby obtaining a fat-in-water emulsion, ii. churning the fat-in-water emulsion, thereby obtaining a water-in-fat emulsion and an aqueous phase, iii. optionally, heating at least the water-in-fat emulsion to a temperature wherein said water-in-fat emulsion liquifies, thereby obtaining an oil-rich liquid phase, and iv. centrifuging the fat-in-water emulsion or the oil-rich liquid phase, thereby obtaining a microbial oil containing fraction. 2. Method according to embodiment 1, further comprising the step of separating the water-in-fat emulsion from the aqueous phase before heating in step (iii). 3. Method according to any of the previous embodiments, wherein the churning is carried out at a temperature where the solid fat content of the fat-in-water emulsion is between 20 and 50 wt.%. 4. Method according to any of embodiments 1-2, wherein the churning is carried out at a temperature of between 5 and 15°C. 5. Method according to any of the previous embodiments, wherein the water-in-fat emulsion is heated in step (iii) to a temperature between 40 and 99 °C. 6. Method according to any of the previë8us embodiments, wherein the mechanical lysing is performed using high-pressure homogenization or bead milling. 7. Method according to embodiment 6, wherein the high-pressure homogenization is conducted at a pressure between 500 and 3000 bar. 8. Method according to embodiment 6, wherein the bead milling is carried out with beads having a diameter between 100 um and 10 mm. 9. Method according to any of the previous embodiments, wherein the method does not comprise the step of extracting by organic solvents. 10. Method according to any of the previous embodiments, wherein the method does not comprise a drying step. 11. Method according to any of the previous embodiments, wherein the fat-in-water emulsion is stored at a temperature between 0 and 99°C for a duration between 1 minute and 5 days. 12. Method according to any of the previous embodiments, wherein the microbial biomass comprises between 20 and 70 wt.% oil on a dry matter basis. 13. Method according to any of the previous embodiments, wherein said oil containing fraction has a solid fat content at 20°C of between 5 and 80 wt.%. 14. Method according to embodiment 13, wherein said oil containing fraction has a solid fat content at 20°C of between 5 and 30 wt.%. 15. Method according to any of the previous embodiments, wherein the particles in the microbial biomass have a D90 of between 1 and 10 um. 16. Method according to any of the previous embodiments, wherein the microbial biomass comprises yeast cells. 17. Method according to embodiment 16, wherein the microbial biomass comprises an oleaginous yeast. 18. Method according to embodiment 17, wherein said oleaginous yeast is Cutaneotrichosporon oleaginosus.

Claims

1. A method for extracting oil from microbial biomass, consisting of the following steps: i. the mechanical lysis of a microbial biomass, whereby a a fat-in-water emulsion is obtained, ii. the churning of the fat-in-water emulsion, resulting in a water-in-fat an emulsion and an aqueous phase are obtained, iii. optional, heat at least the water-in-fat emulsion to a temperature at which the water-in-fat emulsion becomes liquid, whereby an oil-rich liquid phase is obtained, and iv. centrifuging the fat-in-water emulsion or the oil-rich liquid phase, whereby a microbial oil-containing fraction is obtained.

2. Method of working in accordance with one of the preceding claims, further comprising the step of separating the water-in-fat emulsion from the aqueous phase before heating in step iii).

3. Method in accordance with one of the preceding conclusions, involving churning is carried out at a temperature at which the solid fat content of the fat-in-water emulsion lies between 20 and 50 wt.%.

4. Method according to one of conclusions 1-2, whereby the churning is carried out at a temperature between 5 and 15 °C.

5. Method in accordance with one of the preceding claims, whereby the water-in- fat emulsion in step iii) is heated to a temperature between 40 and 99 °C.

6. Method of working in accordance with one of the preceding conclusions, whereby the Mechanical lysis is performed by means of high-pressure homogenization or grinding with beads.

7. Procedure according to conclusion 6, whereby the high-pressure homogenization is performed at a pressure between 500 and 3000 bar.

8. Method according to conclusion 6, whereby grinding with pearls is made with pearls with a diameter between 100 µm and 10 mm.

9. Method of working in accordance with one of the preceding conclusions, whereby the method of working does not include the step of extraction with organic solvents.

10. Method of working in accordance with one of the preceding conclusions, whereby the method of working does not include a dry step.

11. Method in accordance with one of the preceding claims, whereby the bold-in- Water emulsion is stored at a temperature between 0 and 99°C for a duration between 1 minute and 5 days.

12. Procedure according to one of the preceding conclusions, whereby the microbial biomass contains between 20 and 70 wt.% oil on a dry matter basis.

13. Method of working in accordance with one of the preceding claims, whereby the oil-containing fraction has a fixed fat content at 20 °C between 5 and 80 wt.% 14. Method in accordance with claim 13, in which the oil-bearing fraction at 20°C a has a solid fat content between 5 and 30% by weight.

15. Method according to one of the preceding conclusions, in which the particles in the microbial biomass have a D90 between 1 and 10 µm.

16. Method in accordance with one of the preceding conclusions, whereby the microbial biomass contains yeast cells.

17. Method according to conclusion 16, whereby the microbial biomass a contains oil-containing yeast.

18. Method according to claim 17, whereby the oil-bearing yeast Cutaneotrichosporon oleaginosus is.

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