ENRICHMENT OF ARACHIDONIC-ACID - SELECTIVE HYDROLYSIS OF A SINGLE-CELL OIL FROM MORTIERELLA WITH CANDIDA-CYLINDRACEA LIPASE

Three lipases, isolated previously in our laboratory, and a known lipase from Candida cylindracea were screened for the enrichment of arachidonic acid (AA). The enzyme fram;C. cylindracea was the most effective for the production of oil with high concentration of AA. When a single-cell oil from Mortierella alpina, containing 25% AA, was hydrolyzed with this lipase for 16 h at 35 degrees C, the resulting glycerides contained 50% AA at 52% hydrolysis. After this, no further hydrolysis occurred, even with additional lipase. However, when the glycerides were extracted from the. hydrolyzate and were hydrolyzed again with new lipase, the resulting oil contained 60% AA, with a recovery of 75% of its initial AA content. Triglycerides were the main components of the resulting oil, The release of each fatty acid from the oil depended on the hydrolysis rate of its ester. The fatty acid, whose ester is the poorest substrate for the enzyme, is concentrated in the glycerides.