Classifications

• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/64—Fats; Fatty oils; Ester-type waxes; Higher fatty acids, i.e. having at least seven carbon atoms in an unbroken chain bound to a carboxyl group; Oxidised oils or fats
  • C12P7/6436—Fatty acid esters
  • C12P7/6445—Glycerides
  • C12P7/6463—Glycerides obtained from glyceride producing microorganisms, e.g. single cell oil
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
  • C11B1/00—Production of fats or fatty oils from raw materials
  • C11B1/10—Production of fats or fatty oils from raw materials by extracting
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N1/00—Microorganisms, e.g. protozoa; Compositions thereof; Processes of propagating, maintaining or preserving microorganisms or compositions thereof; Processes of preparing or isolating a composition containing a microorganism; Culture media therefor
  • C12N1/005—Microorganisms, e.g. protozoa; Compositions thereof; Processes of propagating, maintaining or preserving microorganisms or compositions thereof; Processes of preparing or isolating a composition containing a microorganism; Culture media therefor after treatment of microbial biomass not covered by C12N1/02 - C12N1/08
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N1/00—Microorganisms, e.g. protozoa; Compositions thereof; Processes of propagating, maintaining or preserving microorganisms or compositions thereof; Processes of preparing or isolating a composition containing a microorganism; Culture media therefor
  • C12N1/06—Lysis of microorganisms
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S435/00—Chemistry: molecular biology and microbiology
  • Y10S435/8215—Microorganisms
  • Y10S435/911—Microorganisms using fungi

Definitions

• This invention relates to an extraction process.
• Vegetable oils can be extracted from dried plant seeds using pressure. This in general leaves vegetable oil in the crushed plant tissue and this may be extracted using a water-immiscible organic solvent, for example hexane.
• microbial oils from whole microbes by hexane extraction.
• the microbial material must be dried usually to a water content of less than 5% (w/w) before the oil can be effectively extracted by hexane. Not only does this involve a considerable consumption of energy because, in general, microbial cells contain at least 70% for example 80 to 95% (w/w) water based on their non-oil content, but we have also found that sensitive oils for example oxygen or heat sensitive oils may undergo chemical reactions in the drying process.
• water-miscible solvents for example isopropanol
• isopropanol may be used.
• Such extractions are in general less selective than those with non-polar solvents and a wide range of other cellular components may be extracted in addition to the oils, for example phospholipids and cell wall components. Evaporation of the water-miscible solvent leaves a residue which must therefore be purified further.
• oils are meant materials which are liquid at the extraction temperature and which are sparingly soluble in water.
• oils recovered from microorganisms are triglycerides.
• This invention comprises a process in which an oil is extracted from oil containing microorganisms which comprises disintegrating the microorganisms and contacting them in the presence of a water content of at least 70% by weight of that originally present in the cellular material and preferably in the presence of substantially all of the original water content of the microorganisms with a water immiscible solvent for the oil, separating the solvent from the microorganisms and recovering the oil from the solvent.
• the invention also comprises a process for extracting a triglyceride from microbial matter containing it in which the triglyceride is released from the cells by pressure homogenisation and the released triglyceride is then extracted by contacting the microbial matter with a water-immiscible solvent for example an al ane suitably having 4 to 12 and preferably 5 to 8 carbon atoms, for example cyclohexane or preferably hexane.
• a water-immiscible solvent for example an al ane suitably having 4 to 12 and preferably 5 to 8 carbon atoms, for example cyclohexane or preferably hexane.
• the microorganism should be disintegrated in the presence of an aqueous culture medium in which it has been cultured, as this avoids the need for separating the microbial matter from the culture medium prior to the process.
• the organism will constitute 5% to 20% by volume of the culture medium.
• the same solvent may be re-used two or more times for extracting successive quantities of disintegrated organism containing triglycerides, thus increasing the triglyceride content of the solvent. This leads to economies in recovering the triglyceride from the solvent by evaporation.
• Such processes may, if desired, be conducted by countercurrent extraction.
• this may be carried out by using a solvent which is less dense than the phase containing the disintegrated microorganism and feeding it at a lower level than a phase which contains the disintegrated microorganism to a vessel in which extraction occurs.
• the vessel may be provided with baffles, restricting vertical flow, which define contact zones between the baffles and in which means is provided for stirring material in the contact zones.
• separated solvent containing the triglyceride may be used together with fresh solvent to extract previously unextracted microorganisms.
• the solvent may be separated by centrifuging.
• the solvent may suitably be a hydrocarbon, for example an alkane which suitably has 4 to 12 and preferably 6 to 10 carbon atoms and is suitably hexane.
• the organisms may be disintegrated by enzyme cell disruption using cell wall lytic enzymes, mechanical methods such as bead milling, colloid milling, disruption by pressure release, impinging jets, ultrasonication and preferably using high shear mixing and/or high pressure homogenisation.
• the disruption should be sufficient to disrupt the cell wall, thus enhancing the access of the solvent to the triglycerides contained within the cell. Any form of pressure homogeniser may be employed for this purpose.
• the dispersion is less stable and may be more readily separated in the absence of a demulsifying agent, for example by gravity settling or use of a centrifuge. It is desirable in this case to increase the triglyceride content of the solvent by extracting successive quantities of microbial material with it.
• This invention therefore comprises a process as aforesaid in which the disintegrated microorganisms are contacted with a continuous phase of the solvent. It is desirable that the ratio of solvent phase to other matter present during the extraction step should be at least 1 to 1, preferably at least 1.5 to 1 and more preferably at least 2 to 1 and suitably at most 10 to 1 and preferably at most 1 to 1.
• a strain of Mortierella alpina was grown in batch culture in an aqueous medium on a mixture of glucose and yeast autolysate to give a culture containing 54.8 g/l of cells containing 24% w/w of a triglyceride oil.
• the fatty acid composition of this oil was determined to be 18.6% w/w 5, 8,11,14-eicosatetraenoic acid (arachidonic acid) .
• the cell suspension was dispersed using a high shear mixer (Ultra Turrax, IKA) then fed to a high pressure homogeniser (Rannie Lab homogeniser, APV) operating at a pressure of 400 bar.
• the resulting cell homogenate was then first mixed with a demulsifying agent (Armogard D5390, Akzo-Nobel, Littleborough) to give a concentration of the demulsifier of 2000 ppm.
• This aqueous phase was then contacted (at ambient temperature and neutral pH) with hexane by high shear mixing (Ultra Turrax, IKA) to ensure good phase contact. A phase ratio of 3:1 aqueous to solvent was used.
• the resulting emulsion was separated by centrifugation at 3000 g for 3 minutes.
• the separated hexane phase was purified from residual fermentation antifoam by passing through a silica gel column (Waters Sep-pak) and evaporated to give the purified triglyceride oil. This oil was analysed for 5, 8,11, 14-eicosatetraenoic acid content by Gas
• the overall triglyceride yield from hexane contact of the aqueous phase was 65.7% based on the initial oil content of the microbial cells.
• the 5, 8,11, 14-eicosatetraenoic acid content of the oil was 28.1% w/w.
• Oil yield was higher from extraction from high pressure homogenised whole cells compared to freeze dried cells and the oil quality was higher in terms of the recovered 5,8,11,14-eicosatetraenoic acid.
• a strain of Mortierella alpina was grown in batch culture in an aqueous medium on a mixture of glucose and yeast autolysate to give a culture containing 46.0 g/l of cells containing 51.0% w/w of a triglyceride oil.
• the fatty acid composition of this oil was determined to be 25.1% w/w 5,8, 11,14-eicosatetraenoic acid (arachidonic acid) .
• the cell suspension was dispersed using a high shear mixer (Ultra Turrax) then fed to a high pressure homogeniser (Rannie) operating at a pressure of 400 bar.
• aqueous phase was then contacted (at ambient temperature and neutral pH) with different quantities of hexane by high shear mixing (Ultra Turrax) to ensure good phase contact.
• Phase ratios of 1:1, 1:1.5, 1:2, 1:2.5, and 1:3 aqueous to solvent were used.
• the resulting mixed phases were separated by centrifugation in graduated test tubes at 3000 g for 3 minutes and the recovery of the initial solvent phase measured.
• a strain of Tirraustocytrium was grown in batch culture in an aqueous medium on a mixture of glucose, yeast extract, peptone and 20 g/l Na 2 S0 4 to give a culture containing 15 g/l of cells containing 30% w/w of a triglyceride oil.
• the composition of the fatty acids of this oil was determined to be 10% w/w 7, 10, 13, 16, 19- docosahexaenoic acid (DHA) .
• the cell suspension was passed twice through a high pressure homogenised (Niro-Soavi Panda Laboratory homogeniser) operating at a pressure of 500 bar.
• This aqueous phase was then contacted (at ambient temperature and neutral pH) with three times the aqueous phase volume of hexane by high shear mixing (Ultra Turrax, IKA) to ensure good phase contact.
• the pooled hexane phases were evaporated and analysed for total triglyceride content and of 4, 7, 10, 13, 16, 19- docosahexaenoic acid (DHA).
• DHA docosahexaenoic acid
• the total triglyceride yield was 91% and the 4, 7, 10, 13, 16, 19- docosahexaenoic acid (DHA) content of the oil was 8.7% w/w.
• the peroxide value (PV) of the oil was measured to be less than 5 milliequivalents of active oxygen per kg.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Wood Science & Technology (AREA)
• Zoology (AREA)
• Genetics & Genomics (AREA)
• Biotechnology (AREA)
• Bioinformatics & Cheminformatics (AREA)
• General Engineering & Computer Science (AREA)
• Biochemistry (AREA)
• Microbiology (AREA)
• General Health & Medical Sciences (AREA)
• Tropical Medicine & Parasitology (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Biomedical Technology (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Virology (AREA)
• Medicinal Chemistry (AREA)
• Cell Biology (AREA)
• Mycology (AREA)
• General Chemical & Material Sciences (AREA)
• Sustainable Development (AREA)
• Fats And Perfumes (AREA)
• Preparation Of Compounds By Using Micro-Organisms (AREA)
• Micro-Organisms Or Cultivation Processes Thereof (AREA)

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Cited By (20)

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Citations (4)

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• 1995
  • 1995-07-18 GB GBGB9514649.4A patent/GB9514649D0/en active Pending
• 1996
  • 1996-07-16 DK DK96924096T patent/DK0843733T3/da active
  • 1996-07-16 US US08/983,250 patent/US6180376B1/en not_active Expired - Lifetime
  • 1996-07-16 WO PCT/GB1996/001703 patent/WO1997004121A1/en not_active Ceased
  • 1996-07-16 JP JP50641897A patent/JP2001507379A/ja not_active Ceased
  • 1996-07-16 CA CA002226427A patent/CA2226427C/en not_active Expired - Lifetime
  • 1996-07-16 EP EP96924096A patent/EP0843733B1/en not_active Expired - Lifetime
  • 1996-07-16 ES ES96924096T patent/ES2158323T3/es not_active Expired - Lifetime
  • 1996-07-16 AU AU64670/96A patent/AU6467096A/en not_active Abandoned
  • 1996-07-16 DE DE69613228T patent/DE69613228T2/de not_active Expired - Lifetime
  • 1996-07-16 AT AT96924096T patent/ATE201907T1/de not_active IP Right Cessation

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