OUTDOOR CULTURE OF ISOCHRYSIS-GALBANA ALII-4 IN A CLOSED TUBULAR PHOTOBIOREACTOR

Growth and fatty acid composition of Isochrysis galbana ALII-4 in batc h and semicontinuous outdoor culture in a closed tubular photobioreact or are reported. Specific growth rate at the exponential phase was 0.3 8 d(-1), higher than that obtained in previous indoor experiments. At biomass concentration above 2 g l(-1) net biomass productivity obtaine d in three successive semicontinuous cultures was 0.32 g l(-1) d(-1). A daily cyclic variation in the fatty acid profile was observed. From morning to afternoon, 14:0, 16:0 and 16:1n7 content increased, althoug h it decreased during darkness renewing the cycle again with daylight. On the other hand, no daily variation was observed in polyunsaturated fatty acid content. The EPA generation rate during linear growth, wit h an average content of 2.56%, was 8.2 mg l(-1) d(-1). The present stu dy was conducted uninterruptedly in February and March, 1994, in Almer ia, Spain (latitude 36 degrees 50' N, longitude 2 degrees 27' W).