Concentration of docosahexaenoic acid from fish oils using Geotrichum sp. FO347-2

Geotrichum sp. FO347-2 could use refined sardine oil as a sole carbon source. Dry cell mass reached a maximum of 0.788 g per g of the oil added for 72 h. Total weight of the cellular lipids was largest around 24 h, when the contents of triglyceride and free fatty acid were 63.6 and 22.2%, respectively. Docosahexaenoic acid (DHA) was incorporated and concentrated in the cellular lipids, and the content reached 25.9% for 24 h, adding sardine oil containing 12.3% DHA. DHA and eicosapentaenoic acid were also concentrated in residual lipids outside the cells. Using tuna head oil containing 26.8% DHA, FO347-2 was compared with Candida guilliermondii FO726A with respect to DHA incorporation. FO347-2 and FO726A accumulated similar amounts of DHA, i.e. 53 and 55 mg, respectively, in 1 g of freeze-dried cells after 24-h cultivation at 30 degrees C. The recovery rates of DHA from the tuna oil for FO347-2 and FO726A were 19.4 and 19.7%, respectively.