EFFECTS OF TEMPERATURE AND GROWTH-PHASE ON LIPID AND BIOCHEMICAL-COMPOSITION OF ISOCHRYSIS-GALBANA TK1

The lipid and biochemical composition of the haptophyte Isochrysis gal bana TK1 was examined. Cultures were grown at 15 degrees C and 30 degr ees C, and harvested in the exponential and early stationary growth ph ases. Carbohydrate and protein content varied at the two culture tempe ratures and growth phases. The highest protein content was found at th e exponential growth phase at 15 degrees C, and the highest carbohydra te content was found at the stationary phase at the same culture tempe rature. Lipid accumulated in the stationary growth phase and its conte nt was higher at 30 degrees C than at 15 degrees C regardless of the g rowth phase. The neutral lipids were the major class of lipid found in all the cultures. The stationary phase culture had a higher proportio n of neutral lipids than the exponential phase culture and the proport ion decreased slightly when culture temperature was increased from 15 degrees C to 30 degrees C. Phospholipid levels remained constant at th e two temperatures, but slightly decreased in the stationary phase. Gl ycolipids in the exponentially growing cells were higher than those fr om stationary growth phase and increased with temperature. Polyunsatur ated fatty acids (PUFAs) predominated in glycolipids and phospholipids . Cells grown at 15 degrees C contained higher proportion of 18:3 (n-3 ) and 22:6 (n-3) with a corresponding decrease in 18:2 (n-6), monounsa turated and saturated fatty acids.