Secretive Production of Long-chain Fatty Acids by Microorganisms

Research Project

Project/Area Number	59860010
Research Category	Grant-in-Aid for Developmental Scientific Research
Allocation Type	Single-year Grants
Research Field	発酵・醸造
Research Institution	Hiroshima University
Principal Investigator	FUKUI Sakuzo 広島大学, 工, 教授 (60013299)
Project Period (FY)	1984 – 1985
Project Status	Completed (Fiscal Year 1985)
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)
Keywords	Secretive production of long-chain fatty acids / パルミチン酸 / 長鎖脂肪酸分泌醗酵
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.