Microbial oils with lowered pour points, dielectric fluids produced therefrom, and related methods
View Patent ↗Methods and compositions for the production of dielectric fluids from lipids produced by microorganisms are provided, including oil-bearing microorganisms and methods of low cost cultivation of such microorganisms. Microalgal cells containing exogenous genes encoding, for example, a sucrose transporter, a sucrose invertase, a fructokinase, a polysaccharide-degrading enzyme, a lipid pathway modification enzyme, a fatty acyl-ACP thioesterase, a desaturase, a fatty acyl-CoA/aldehyde reductase, and/or an acyl carrier protein are useful in manufacturing dielectric fluids.
1. A method of producing an RBD microbial oil, wherein the microbial oil has a pour point of less than about −5° C., and wherein the fatty acid composition of the microbial oil is at least 50 area % C18:1 fatty acids and less than 10 area % C18:2 fatty acids, as determined by fatty acid methyl ester gas chromatography flame ionization detection methods, the method comprising:
a. cultivating a genetically engineered microbe engineered to express one or more exogenous genes until the microbe has at least 10% oil by dry weight;
b. separating the oil from the microbe; and
c. subjecting the oil to refining, bleaching, deodorizing or degumming to produce RBD microbial oil.
2. The method of claim 1 , wherein the microbial oil has a pour point of between about −10° C. and about −40° C.
3. The method of claim 1 , wherein the method additionally comprises adding an antioxidant, metal ion deactivator, corrosion inhibitor, demulsifier, anti-wear additive, pour point depressant, or anti-hydrolysis compound to the RBD oil.
4. The method of claim 1 , wherein the genetically engineered microbe is Prototheca or Chlorella.
5. The method of claim 4 , wherein the genetically engineered microbe is Prototheca moriformis.
6. The method of claim 1 , wherein the one or more exogenous genes encode(s) sucrose invertase or fatty acyl-ACP thioesterase.
7. The method of claim 6 , wherein the one or more exogenous genes encode(s) two or more fatty acyl-ACP thioesterases.
8. The method of claim 6 , wherein the one or more exogenous genes encode(s) sucrose invertase and one or more fatty acyl-ACP thioesterases.
9. A method of producing a product comprising microbial oil, wherein the product has a pour point of less than about −5° C., and wherein the fatty acid composition of the microbial oil is at least 50 area % C18:1 fatty acids and less than 10 area % C18:2 fatty acids, as determined by fatty acid methyl ester gas chromatography flame ionization detection methods, the method comprising:
a. subjecting a first microbial oil to refining, bleaching, deodorizing or degumming to produce RBD oil, wherein the RBD oil is characterized by an initial pour point and a first temperature;
b. lowering the temperature of the RBD oil to a second temperature, which is lower than the first temperature;
c. holding the RBD oil at the second temperature; and
d. filtering the RBD oil at the second temperature to provide a second microbial oil characterized by a second pour point that is lower than the initial pour point, wherein the second pour point is less than about −5° C.
10. The method of claim 9 , wherein the microbial oil has a pour point of between about −10° C. and about −40° C.
11. The method of claim 9 , wherein the method additionally comprises adding an antioxidant, metal ion deactivator, corrosion inhibitor, demulsifier, anti-wear additive, pour point depressant, or anti-hydrolysis compound to the second microbial oil.
12. The method of claim 9 , wherein the method additionally comprises producing the first microbial oil by:
a. cultivating a genetically engineered microbe engineered to express one or more exogenous genes until the microbe has at least 10% oil by dry weight; and
b. separating the oil from the microbe to produce the first microbial oil.
13. The method of claim 9 , wherein the first temperature is between above 15° C. to about 50° C., and the second temperature is between about −15° C. and about 15° C.
14. The method of claim 9 , wherein the product is a lubricant, a hydraulic fluid, an industrial oil, or a dielectric fluid.
15. The method of claim 14 , wherein the product is a dielectric fluid.
16. The method of claim 15 , wherein the dielectric fluid further comprises an antioxidant, a metal ion deactivator, a corrosion inhibitor, a demulsifier, an anti-wear additive, a pour point depressant, or an anti-hydrolysis compound.