Enhanced production of lipids containing polyenoic fatty acids by very high density cultures of eukaryotic microbes in fermentors

Abstract

The present invention provides a process for growing eukaryotic microorganisms which are capable of producing lipids, in particular lipids containing polyenoic fatty acids. The present invention also provides a process for producing eukaryotic microbial lipids.

1 .- 22 . (canceled) 
     
     
         23 . A biomass of microorganisms having highly unsaturated fatty acids, wherein said biomass is produced by a process of conducting a fermentation of the microorganisms in a fermentation medium comprising a carbon source and a limiting nutrient source, the process comprising:
 a) providing the fermentation medium comprising the carbon source and the limiting nutrient source;   b) adding the microorganisms to the fermentation medium;   c) adding an additional amount of the carbon source and limiting nutrient source to the fermentation medium to increase the biomass density of the fermentation medium to at least about 100 g/L on a dry cell weight basis;   d) adding an additional amount of the carbon source while limiting the amount of limiting nutrient source added to the formulation medium to induce lipid production by the microorganisms; and   wherein the microorganisms are of the order Thraustochytriales, and produce at least 15% by weight of the dry cell weight of the biomass as lipids.   
     
     
         24 . The biomass of  claim 23 , wherein the process further comprises e) recovering at least some of the lipids from the microorganisms. 
     
     
         25 . The biomass of  claim 23 , wherein the microorganisms are selected from the group consisting of  Thraustochytrium, Schizochytrium,  and mixtures thereof 
     
     
         26 . The biomass of  claim 23 , wherein the highly unsaturated fatty acids are selected from the group consisting of docosahexaenoic acid, docosapentaenoic acid, eicosapentaenoic acid, arachidonic acid and mixtures thereof. 
     
     
         27 . The biomass of  claim 26 , wherein the highly unsaturated fatty acids are eicosapentaenoic acid. 
     
     
         28 . The biomass of  claim 23 , wherein at least 25% of the lipids is docosahexaenoic acid. 
     
     
         29 . The biomass of claim  1 , wherein the process produces lipids at an average rate of at least 0.5 g/L/hr and wherein at least 25% of the lipids is docosahexaenoic acid. 
     
     
         30 . A biomass of microorganisms having highly unsaturated fatty acids, wherein said biomass has a density of 100 g/L on a dry cell weight basis of the fermentation medium that it is isolated from, and wherein at least 15% by weight of the dry cell weight of the biomass is lipids. 
     
     
         31 . The biomass of  claim 30 , wherein said biomass has a density of 130 g/L on a dry cell weight basis of the fermentation medium that it is isolated from. 
     
     
         32 . The biomass of  claim 30 , wherein said biomass has a density of 150 g/L on a dry cell weight basis of the fermentation medium that it is isolated from. 
     
     
         33 . The biomass of  claim 30 , wherein the microorganisms are selected from the group consisting of  Thraustochytrium, Schizochytrium,  and mixtures thereof 
     
     
         34 . The biomass of  claim 30 , wherein the highly unsaturated fatty acids are selected from the group consisting of docosahexaenoic acid, docosapentaenoic acid, eicosapentaenoic acid, arachidonic acid and mixtures thereof. 
     
     
         35 . The biomass of  claim 30 , wherein at least 30% by weight of the dry cell weight of the biomass is lipids. 
     
     
         36 . An oil extracted from a biomass of  claim 23  or  claim 30 . 
     
     
         37 . The oil as recited in  claim 36 , wherein said oil is a crude oil extracted from the biomass without further processing. 
     
     
         38 . A feed product that contains a biomass of any one of  claims 23 - 35  or an oil of any one of  claims 36 - 37 . 
     
     
         39 . The feed product of  claim 38 , wherein said feed product is a feed or feed supplement. 
     
     
         40 . The feed of  claim 38 , wherein said feed is an animal feed. 
     
     
         41 . The feed of  claim 38 , wherein said feed is an aquaculture feed.