EFFECT OF TEMPERATURE AND GLUCOSE SUPPLY ON THE PRODUCTION OF POLYUNSATURATED FATTY-ACIDS BY THE FUNGUS MORTIERELLA-ALPINA CBS-343.66 IN FERMENTER CULTURES

The fungus Mortierella alpina CBS 343.66 was grown in a fermentor at d ifferent pH, temperatures and supplies of carbon source (glucose) in o rder to optimize the culture conditions for rapid biomass and lipid pr oduction with a high proportion of polyunsaturated fatty acids, especi ally arachidonic acid (AA). Good growth and lipid production with 31% AA was obtained at pH 6.5 and 25-degrees-C. A temperature decrease to 18-degrees-C gave a significantly higher degree of polyunsaturated fat ty acids. Eicosapentaenoic acid was not detected at 25-degrees-C, but was formed at 18-degrees-C at about 10%. The AA concentration was simi lar for 18-degrees-C and 25-degrees-C (around 30%): 18-degrees-C allow ed relatively good growth and had a beneficial effect on the fungus mo rphology, i.e. pellets were formed. Best lipid production and a AA con tent of up to 33% was achieved at an excess of glucose (carbon source) and a deficit of ammonium chloride (nitrogen source). The percentage of AA of the total fatty acid composition was constant as long as gluc ose was present. At glucose exhaustion, the proportion of AA increased to 57%. The increase in AA corresponded to a decrease in palmitic aci d, stearic acid and oleic acid.