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  • Processing of Crude Algal Oils and Production of EPA and DHA Concentrates

    Rick Green, Ph.D.

    POS Bio-Sciences

    Saskatoon, SK

    BIO Pacific Rim Summit

    December 8, 2014

  • Overview of POS Bio-Sciences

    • POS is a fee-for-service technology

    development organization.

    • Specialize in process development for

    ingredients along with globally recognized

    analytical services.

    • Extraction and isolation of components from

    plant and microbial sources.

    • Extensive experience in algal oil processing

    and fractionation to produce EPA and DHA

    concentrates.

    • Manage a multi-scale processing facility.

    • 38 year technology development history.

  • Overview of POS Bio-Sciences

    New process/product concept

    Laboratory

    (2 kg)

    Mini-pilot scale trials

    (20 kg)

    Pilot scale development

    (200 kg - Tonnes)

    Custom manufacturing

    (10 T – 600 T)

    Commercial production

  • Components of Extracted

    Microalgae Crude Oil

    Lipids*

    • Neutral

    • Triacylglycerols (TAG)

    • Unsaturated (including n-3)

    • Saturated

    • Hydrocarbons

    • Sterols

    • Waxes

    • Pigments – chlorophyll, astaxanthin

    • Tocopherols

    • Polar

    • Phospholipids

    • Glycolipids

    • Free fatty acids

    Elements

    • S, Cl, Na, heavy metals

    * Some components

    beneficial, some not.

  • Non-lipid components

    • Undesirable Contaminants

    • Oxidized compounds

    • Pesticide residues

    • Proteins/peptides

    • Polysaccharides

    • Sugars

    • Moisture

    • Further processing of crude oils is required to remove the

    objectionable components – can have significant effect on yields.

    Components of Extracted

    Microalgae Crude Oil

  • Purification and Fractionation of

    Microalgae Oil

    • Increase stability of the oil

    • Purify for further processing

    • Increase functionality of the oil

    • Produce valuable co-products

    • Enhance economic viability

    Co-products

    • Generally, co-products for functional foods,

    nutrition and health benefits are higher in

    value

    • E.g. astaxanthin, EPA, DHA

  • Downstream Processing Flow for Oil and

    Co-products from Microalgae

    Microalgae

    Concentrated

    unsaturated fraction

    (DHA, EPA)

    Crude Oil

    Refined oil,

    Saturates

    Meal

    feed

    food ing.

    fertilizer

    protein

    carbohydrates

    pigments,

    antioxidants,

    antimicrobials

  • (Should be processed

    under heavy N2)

    Crude oil

    Degumming

    Alkali-refining

    Bleaching Deodorization

    AO fortification &

    Packaging

    Water washing

    Fractionation

    Processed oil

    Omega-3 rich

    fraction

    Waxes, polar cmpds.

    Phospholipids & Glycolipids

    Free Fatty acids (as soaps)

    Pigments,

    elements

    n-3 Oil

    Microalgal Oil Processing Schematic

    Wash or Trisyl Treatment Trace soaps

  • Water washing

    • Crude oil with 15% (w/w) warm water (~55-60°C under N2).

    • Centrifuge (at ~55-60°C) – separation of water and oil phases.

    Target:

    To remove – Sugars

    Polysaccharides

    Fines

    Mucilaginous compounds

    Proteins, etc.

    Avoid if oil is high in polyunsaturates

    Water Washing

    Crude Algal Oil

  • Desludger

    Hydratable gums – water degumming

    Non-hydratable gums – acid degumming

    • Oil is mixed with water (2% w/w) or acid (0.2% w/w) & water (2% w/w)

    Acid: Citric or Phosphoric acid.

    • Centrifuge: gives semi-solid gum phase and liquid oil phase

    (degummed oil).

    Washed Oil

    Degumming

    • First step of the refining process, designed to remove

    phosphatides (gums) that interfere with subsequent processing.

  • Alternative to Degumming

    • Mixing the oil in acetone will cause precipitation of the polar lipids

    (phospholipids and glycolipids)

    • Need to use explosion proof equipment and a solvent rated facility

    • A more expensive method

    Precipitation of Polar Lipids in Acetone

  • Degummed oil

    • Involves the removal of free fatty acids (FFA)

    • Sufficient caustic is added to convert the FFA to soaps (FFA salts) –

    these are water insoluble.

    • Calculate the required amount of caustic (dilute NaOH solution or

    Baumé) based on free fatty acid content.

    • Required amount of caustic mixes with degummed oil at 60C for

    minimum of 30 min.

    • Centrifuge at 70°C to separate soap and liquid-oil phase

    (alkali-refined oil).

    Alkali Refining

  • Continuous

    Refining Separator

    Alkali Refining FFA Soaps

    OH-C-R + KOH

    O

    K+-O-C-R + H2O

    O

  • Alkali-refined oil

    • Trisyl - an amorphous, synthetic silica hydrogel used to remove small

    amounts of soaps formed during alkali refining of the oil.

    (in lieu of water washing)

    • Due to the polar nature of Omega-3 containing Algae oil, water washing

    is not suitable for removing soap (yield losses may be very high).

    • Calculate the required amount of Trisyl, based on the remaining soap.

    • Trisyl mix with refined oil at 60°C for ~30 min.

    • Filter using frame filters to separate soap adsorbed Trisyl-solids

    and Trisyl-treated oil.

    Trisyl Treatment

  • Bleaching

    • Oil is mixed with an adsorptive clay to remove pigments

    (e.g. chlorophyll) and elements/metals.

    • Also removes some breakdown products of any fatty

    acid/TAG oxidation (e.g. peroxides, ketones)

    Filter Press Reactor for bleaching

    Trisyl treated oil

  • Deodorization

    Continuous Column Deodorizer

    (250 kg/hr)

    Column packing

    Remove odors and flavors from high oils/fractions.

    Bleached oil

  • Fractionation of Oil & Production of

    DHA & EPA Concentrates

    Dr. Udaya Wanasundara

    Principal Scientist

    Lipids & Co-Products

  •  Low temperature crystallization (in solvent)

     Urea Adduct Formation

     Short Path Distillation/Fractional Distillation

     Supercritical fluid extraction & fractionation

     Chromatographic separation (CPC, HPLC)

    Esterification is usually required prior to the concentration

    All these methods have advantages and disadvantages

    Important consideration should be product quality and the cost of production

    Methods for Concentration of Omega-3 Fatty Acids

  • Fatty Acid Melting point (C)

    Melting point of a FA depends

    on the chain length and the

    number of double bonds

    (unsaturation) present.

    Saturates – high MP

    PUFA – low MP

    Low Temperature Crystallization

  • Example Conditions

    • Algae oil (TAG or FFA) • Solvents: Hexanes or Acetone • Oil-to-solvent ratio: 1:4 (w/v) • Temperature: -25oC • Time: 24h with slow mixing • Separate crystals by filtration • Evaporate solvent from liquid

    fraction (non-crystallized

    fraction)

    Low Temperature Crystallization

    Non-crystallized fraction

    (PUFAs)

    Crystallized fraction

    (Saturated fatty acids)

    Jacketed Tank

  • Enrichment of PUFAs by Low Temperature Crystallization

    AcetoneHexanes

    12.0

    15.1

    37.2

    TAG

    8.2

    10.1

    27.8

    TAG

    13.8

    17.5

    40.6

    11.8

    12.5

    31.6

    6.8

    8.4

    22.2

    EPA (%)

    DHA (%)

    Total 3 (%)

    FFAFFA

    Starting

    Marine

    Oil

    Fatty Acid

    Esters

  • Urea Adduct Formation

    5.67Å

    C O

    HN2 HN2

    FFA/EE

    mixture

    Urea:CO(NH2)2 (Tetragonal)

    Urea & Straight Chain

    Molecules (Hexagonal)

    PUFA

    (NUCF) +

    UCF

    8-12Å FA

    • In a FFA or ethyl ester (EE) mixture, saturates

    and mono-unsaturates

    are complexed with urea

    (UCF).

    • Presence of double bonds increases the

    bulk of the molecule and

    reduces the likelihood of

    its complexation with

    urea, i.e. PUFAs remain

    in the liquid and are

    referred to as non-urea

    complexing fraction

    (NUCF).

  • • Dissolve urea in 95% ethanol or methanol.

    • Add either FFA or Ethyl ester form of Omega-3 rich oil

    • Mix and leave at room temperature or ~4C to form crystals (Urea/fatty acid complex or adduct).

    During crystallization, straight saturated and mono-unsaturated fatty acids are form complex with urea (Urea Complexed Fraction, UCF) and PUFAs remain in the liquid (Non-Ure