Processes for extraction of omega-3 containing biomass oils from dried biomass

Abstract

A method for using mechanical cartridges for the extraction of highly bioavailable omega-3 containing biomass oils from algal biomass is presented. Cartridges may contain an inner bore with an inlet and outlet, and may be amenable to adjustments in pressure and temperature, thereby permitting solvent-based extraction of algal biomass in which solvent temperature, pressure, retention time and flow rate are controllable.

1 . A method for extraction of a biomass oil, which may include lipids, from a dried biomass, comprising:
 1) obtaining a mechanical cartridge with an inner bore and inlet and outlet ends permitting solvent flow, capable of being temperature controlled and pressurized and of containing temperature controlled and pressurized solvent at ranges sufficient to extract a target biomass oil, such as to melt lipids;   2) filling the mechanical cartridge with a target biomass oil-containing portion of the biomass;   3) if required for targeted extraction, heating or cooling the mechanical cartridge to a predetermined temperature range; and,   4) pumping a solvent through the biomass-filled mechanical cartridge at a temperature, pressure, retention time and flow rate sufficient to extract the target biomass oil in the target biomass oil-containing portion of the biomass and thereby extracting the target biomass oil from portions of the biomass retained in the mechanical cartridge under the same conditions.   
     
     
         2 . The method of  claim 1  wherein the mechanical cartridge has an inner diameter of between 25 and 1000 mm and a straight length, not including inlet and outlet connections of 100 to 1000 mm. 
     
     
         3 . The method of  claim 2  wherein the mechanical cartridge has an inner diameter of between 300 and 500 mm and a straight length, not including inlet and outlet connections of 700 to 300 mm. 
     
     
         4 . The method of  claim 1  wherein the biomass comprises an algal biomass. 
     
     
         5 . The method of  claim 4  wherein the biomass comprises an autotrophic algal biomass. 
     
     
         6 . The method of  claim 5  wherein the biomass comprises a  Nannochloropsis, Trachydiscus  or  Chlorella  biomass. 
     
     
         7 . The method of  claim 1  wherein the inlet and outlet ends of the mechanical cartridge comprise grates, screens or gates configured to provide flow distribution of the solvent through the biomass and limit solid material from passing out of the mechanical cartridge. 
     
     
         8 . The method of  claim 1  wherein the temperature control comprises heating of the mechanical cartridge and the method of heating is selected from the group consisting of one or more of jacketing, passing a heating fluid around the exterior of the mechanical cartridge, immersion in a heating solution, by electric resistance and by induction. 
     
     
         9 . The method of  claim 1  wherein the solvent comprises an alcohol, hexane, heptane or carbon dioxide. 
     
     
         10 . The method of  claim 1  wherein the targeted biomass oil comprises a polar lipid. 
     
     
         11 . The method of  claim 1  wherein the targeted biomass oil comprises a non-polar lipid. 
     
     
         12 . The method of  claim 1  wherein the solvent is heated to a range between 40 degrees C. and 150 degrees C. during extraction of the lipid. 
     
     
         13 . The method of  claim 1  wherein the solvent is heated to a range between 70 degrees C. and 110 degrees C. during extraction of the lipid. 
     
     
         14 . The method of  claim 1  where operating pressure of the solvent is between 5 bar and 100 bar. 
     
     
         15 . The method of  claim 1  where operating pressure of the solvent is between 25 bar and 35 bar. 
     
     
         16 . The method of  claim 1  wherein the targeted biomass oil is a lipid, and the lipid-containing portion of the biomass is subjected as the extracted lipid to further processing subsequent to the steps of  claim 1 . 
     
     
         17 . The method of  claim 16  wherein the further processing subsequent to the steps of  claim 1  comprise fractionation between polar and non-polar lipids. 
     
     
         18 . The method of  claim 16  wherein the further processing subsequent to the steps of  claim 1  comprise liquid-to-liquid fractionation. 
     
     
         19 . The method of  claim 17  wherein the further processing comprises the steps of:
 a. Where the extracted biomass comprises an algal biomass, sequestering the algal biomass; 
 b. Extracting the algal biomass with a polar solvent to form a polar extract of algal lipids with a low water content; 
 c. Further extracting the polar extract with an organic solvent to separate out a fraction of non-polar lipids, thus substantially removing a non-polar lipids fraction in an organic solvent layer; 
 d. separating out a polar layer containing pigments and polar lipids; 
 e. adding water to the polar layer and further extracting with sequential additions of the organic solvent, whereby a pigment fraction is substantially removed to form a water-polar layer containing the polar lipids; and, 
 f. separating out a polar lipids fraction from the water-polar layer by evaporation. 
 
     
     
         20 . The method of  claim 16  wherein the further processing comprises the steps of:
 a. Where the extracted biomass comprises an algal biomass, sequestering the algal biomass whereby an algal oil or extract comprising both polar and non-polar lipid fractions, and having at least some chlorophyll concentration; is obtained 
 b. using polarity characteristics of the polar and non-polar lipid fractions to segregate polar from non-polar components in the algal oil or extract; 
 c. removing substantially all of the at least some chlorophyll concentration from the non-polar containing fraction; and 
 d. re-combining the polar and non-polar lipid fractions to produce a low to substantially one lacking any chlorophyll content oil composition.