EFFECT OF SALINITY ON FATTY-ACID COMPOSITION OF A GREEN MICROALGA FROM AN ANTARCTIC HYPERSALINE LAKE

The major fatty acids in a Dunaliella sp. isolated from an Antarctic h ypersaline lake were 18:3 omega 3, 16:0 and 16:4 omega 3, which togeth er accounted for 72-75% of the total fatty acids in the cells. The fat ty acid composition was modified by varying the salinity in the growth medium. With salinity increasing from 0.4 M to 4 M NaCl in the cultur es, the proportion of total saturated and monounsaturated fatty acids increased, while total polyunsaturated fatty acids decreased. All the omega 3 fatty acids showed negative trends to salinity. Total polyunsa turated fatty acid content was ca 10% higher in the low salinity cultu re. The results obtained suggest that increasing salinity in the growt h medium increases the degree of fatty acid saturation and, hence,redu ces the fluidity and permeability of the microalgal membranes. (C) 199 7 Elsevier Science Ltd.