Carbon dioxide fixation and polyunsaturated fatty acid production by the red alga Porphyridium cruentum

Focusing on CO2 fixation, photoautotrophic cultivation of the red alga Porphyridium cruentum was investigated by means of a batch culture under a 5% CO2-enriched atmosphere. The algal growth kinetics was successfully described with a logistic model, and simulation of a continuous culture under the optimum growth conditions (30 degrees C, 12 klux and 1.18 g-cells/L) showed that the algal CO2-fixation activity could reach 0.66 g-CO2/(L X d). Under the same growth conditions, eicosapentaenoic acid (20:5 n-3, EPA) and arachidonic acid (20:4 n-6, ARA) yields were similarly calculated to be 3.6 mg-EPA/(L X d) and 6.5 mg-ARA/(L X d), respectively