Abstract
An autotrophic unicell-algae Isochrysis galbana,obtained from Tong Kung Marine Laboratory,was the strain used in this study Initially,the strain was cultivated in a flask. The objective of this study was to obtain the optimum operating condition for the yield of biomass and DHA via changing the intensity of light(3000 lux、5000 lux、9000 lux),light of preculture(5000 lux□3000 lux、9000 lux□5000 lux、3000 lux□9000 lux),culture temperature(20℃、25℃、30℃) The results indicated that we attained the highest yield of DHA was 3.93 mg/L,which was attained when the intensity of light was 5000 lux,and under changing the preculture condtions, we know that Microalgaes are adapt to the enviorment which transfer worse conditiond to better condition .The fitness temperature is 25℃ and the DHA yield amount to 3.21 mg/L.in a 5L photobioreactor. The objective of this study was to obtain the optimum operating condition for the yield of biomass and DHA via changing the intensity of light(3000 lux、7000 lux、9000 lux), the flux of air(125 ml/min、250 ml/min、350 ml/min), and the circulation rate of the liquid(0.5 L/min、1 L/min、3 L/min). The results indicated that we attained the highest yield of DHA was 5.68 mg/L,which was attained when the intensity of light was 7000 lux, the flux of air is 250 ml/min, and the circulation rate is 1 L/min.