1993 Fiscal Year Final Research Report Summary
Production of polyunsaturated fatty acids by microorganisms
| Project/Area Number |
04660115
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
応用微生物学・発酵学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
SHIMIZU Sakayu Fac.Agric.Kyoto Univ.Prof., 農学部, 教授 (70093250)
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| Co-Investigator(Kenkyū-buntansha) |
KATAOKA Michihiko Fac.Agric.Kyoto Univ.Assist., 農学部, 助手 (90252494)
KOBAYASHI Michihiko Fac.Agric.Kyoto Univ.Lec., 農学部, 講師 (70221976)
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| Project Period (FY) |
1992 – 1993
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| Keywords | arachidonic acid / polyunsaturated fatty acid / Mortierella alpina / dihomo- -linolenic acid |
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| Research Abstract |
There are many advantages of using microorganisms as practical sources of long chain polyunsaturated fatty acids(PUFAs). After screening a wide variety of microorganisms, fungal mycelia were found to be new and rich sources of C_<20> PUFAs of dietary and pharmacological importance. A soil isolate, Mortierella alpina 1S-4, produced arachidonic acid(ARA)at 4.3 g/L(274 mg/g dry mycelia)in a conventional carbohydrate medium. This value accounted for more than 65% of the total fatty acids in the extracted lipids from the mycelia. Eicosapentaenoic acid(EPA)was also produced when M.alpina was grown at lower temperatures(i.e., 12ﾟC). This temperature-dependent formation of EPA was found to be due to the activation of an enzyme, which catalyzes desaturation at the n-3 position of ARA by low temperature. The fungus converted oils containing alpha-linolenic acid(ALA), such as linseed oil and perilla oil, to an oil containing EPA with a concentration of 1.88 g EPA/L.This conversion was independent of the growth temperature. When grown in the presence of sesame oil, the same fungus produced dihomo-gamma-linolenic acid(DGLA)at a level of 2.17 g DGLA/L, with an accompanying marked decrease in ARA production. This was found to be due to specific inhibition of the DELTA5-desaturase by sesamin and related lignan compounds present in the oil.
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