| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1985: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1984: ¥5,500,000 (Direct Cost: ¥5,500,000)
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| Research Abstract |
We isolated the mutants of Candida lipolytica, which produce longchain fatty acids in the culture medium. The procedure for the isolation of the mutant consisted of two steps: ( <i> ), isolation of low density cell, and ( <ii> ), screening of fatty acid-excretive cell on plate culture. One of the mutants could produce more than 10 mg of long-chain fatty acids per ml of culture medium as crystals. The products were mainly palmitic acid with stearic acid as by-product; these are all free-form. The yield was strongly affected by both glucose concentration and <O_2> supplyment; ( <i> ) glucose was step-wisely added to the culture to keep a concentration of higher than 1 %, and ( <ii> ) weak aeration was performed for repression of respiration. Subsequently, a high yield of the production, such as approximately 20 % per consummed glucose by weight, was achieved. From the metabolic studies on fatty acid, the theoretical fermentation formula is considered to be 4 Glucose + <O_2> = Palmitic acid + 8 <CO_2> 8 <H_2O> + A Cal. Thus, the high yield decribed above corresponds to 55 % of the theoretical yield.
Palmitic acid, a main product, however, is not significant for industrial usage, unfortunatly. Some attempts, then, were made for selection of microorganisms accumulating physiologically valuable fatty acids in intra- and extra-cellular spaces. A Zygomycetous fungus, Conidiobolus heterospora was obtained as a producer of arachdonic acid, an eicosatetra-enoic acid; a yield was approximately one gram per liter of culture.
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