Effect of growth temperature on the fatty acid composition of a blue-green alga

Abstract

The fatty acid composition of the blue-green alga, Anacystis nidulans, was investigated by gas-liquid chromatography at four different growth temperatures with illumination, aeration, cell density, medium composition, and growth rate kept constant. At all temperatures palmitic acid and a hexadecenoic acid presumed to be palmitoleic totaled approximately 90% of the fatty acids present but the ratio of the hexedecenoic to palmitic decreased as the temperature was raised. An octadecenoic and tetradecenoic (probably oleic and myristoleic, respectively) were also present and traces of a heptadecenoic acid and of others were detected. At 26[deg], 32[deg], and 35[deg], the ratio of total unsaturated to saturated acids remained approximately 1[middle dot]0 although the qualitative composition changed, but at 41[deg] the saturated acids predominated, the ratio being 0[middle dot]7. In contrast to other algae and higher plants, polyunsaturated acids were absent in Anacystis which in this way resembles the photosynthetic bacteria.