光强和温度对球等鞭金藻(Isochrysis sphaerica)生长及其脂肪酸的影响

Effect of light intensity and temperature on growth and fatty acid composition of Isochrysis sphaerica

本研究测定了光照强度为16～58μmol/(m2.s)和15～30℃条件下球等鞭金藻(Isochrysis sphaerica)的生长曲线以及脂肪酸组成和含量。结果表明,在设置的光照强度范围内,光照强度越强,微藻的生长速度越快。光强对各种脂肪酸的含量影响有差异,过低和过高都不利于藻体内多不饱和脂肪酸(Polyunsaturated Fatty Acids,PU-FAs)的积累。当光强为24μmol/(m2.s)时二十二碳六烯酸(Docosahexaenoic Acid,DHA,C22∶6 n-3)的积累量最高,占总脂肪酸的11.77%。球等鞭金藻的最适生长温度在20～25℃之间,低温条件有利于不饱和脂肪酸的积累。光强20μmol/(m2.s)、温度20℃条件下总不饱和脂肪酸(Total Unsaturated Fatty Acids,TUFAs)含量最高,达64.99%;同样的光强,温度15℃条件下DHA占总脂肪酸的12.19%。可见适宜的光强和温度是利用球等鞭金藻收获PUFAs的关键。

Growth curve and fatty acids composition of Isochrysis sphaerica under different light intensity and temperatures were examined in this study. Results showed that light intensity significantly affected the growth rates. The higher the light intensity, the faster the growth of I. sphaerica. Contents of PUFAs （polyunsaturated fatty acids） were affected if the light intensity were higher than 58μmol/（m^2·s） and lower than 16μmol/（m^2·s）. Proportion of DHA （docosahexaenoie acid, C22：6 n -3） reached to 11.77% of total fatty acid when light intensi- ty was 24μmol/（m^2·s）. The optimal growth temperature for I. sphaerica was between 20℃ to 25℃. Low temperature was beneficial to TUFAs （ total unsaturated fatty acids） accumulation. Under 20μmol/（m^2·s） of light intensity, the TUFA proportions reached to its highest of 64.99% at 20℃, and the DHA proportion reached to its highest of 12.19% at 15℃. It indicated that light intensity and temperature were important to microalgae PUFAs aecumulation in I. sphaerica.