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The Phaeodactylum tricornutum growth and reproduction quick easy culture, rich in polyunsaturated fatty acids especially EPA and polyunsaturated fatty acids ideal material for research quality and aquatic animals bait. Many environmental factors can affect the Phaeodactylum tricornutum growth and fatty acid composition, the use of simple and feasible environmental regulation, does not require too high costs can change the fatty acid composition and percentage content. This paper studies the impact of nutritional elements phosphorus and silicon refers tricornutum algae cell density, chlorophyll a and lutein content and fatty acid composition, in order to provide a theoretical reference for the industrial-scale production of high-quality food and the EPA. First Phaeodactylum tricornutum cultured selection of different phosphorus concentration medium, set five phosphorus concentration gradient, 0 μmol / L, 9.1μmol / L, PRD / L, 36.6μmol / L, 73.2μmol / L phosphorus concentration f / 2 medium 0,1 / 4,1 / 2,1,2, cultured Phaeodactylum tricornutum to the end of exponential growth, different phosphorus concentration on cell density, specific growth rate, optical density, chlorophyll a and lutein content and fatty acid composition. The results show that the the Phaeodactylum tricornutum cell density, optical density, and specific growth rate, phosphorus concentration of 0 μmol / L to 36.6μmol / L range with increasing phosphorus concentration increase, 36.6μmol / L with no significant 73.2μmol / L group differences. PUFAs EPA and the percentage of the phosphorus concentration 0μmol / L ~ 73.2μmol / L range with increasing phosphorus concentration was an increasing trend; According to our results, select the phosphorus concentration 36.6μmol / L (ie f / 2) tricornutum refers to the algae culture to the fatty acid content of the end of exponential growth, and then transferred to phosphate-free f / 2 medium 0h, 12h, 24h, 48h, 72h, 96h phosphorus limit set f / 2 medium for the control group . The results show that phosphorus restriction significantly reduced the the Phaeodactylum tricornutum content of chlorophyll a, phosphorus limit 96h content 1.24ug/ml decreased by 20.16% compared with the control group; and phosphorus restriction 12h and 48h, EPA percentage of 22.46% and 21.96%, respectively, compared with the control group, an increase of 12.30% and 5.53%, respectively; phosphorus limit 24 h and 96 h, the EPA the percentage of 20.84% ??and 22.01%, respectively, compared with the f / 2 control group decreased by 7.58 % and 11.56%. Phaeodactylum tricornutum a different silicon concentration medium culture, the silicon concentration is set to 5 gradient, 0μmol / L, 12μmol / L, 24μmol / L, 48μmol / L, 96μmol / L of each culture liquid silicone concentration respectively, f / 2 medium, 0,1 / 4,1 / 2,1,2 cultured Phaeodactylum tricornutum to the end of exponential growth, the results show that the Phaeodactylum tricornutum cell density, specific growth rate and optical density 0μmol / L ~ 48μmol / L the highest silicon concentration range increases with increasing silicon concentration 96μmol / L and 48μmol / L compared than the growth rate of no difference in the optical density was significantly lower than 48μmol / L group, the specific growth rate in the silicon concentration is 48μmol / L its value of 0.18, compared with 0μmol / L group increased by 10.70%. EPA percentage content in the silicon concentration 24μmol / L reached the maximum 29.24%, respectively, compared 0μmol / L, 12μmol / L, 48μmol / L, 96μmol / L group higher than the 18.81%, 11.73%, 14.53%, 13.33%; Based on the above experimental results, select the silicon concentration 48μmol / L (f / 2) Phaeodactylum algae culture to the fatty acid content of the end of exponential growth, then transferred to a silicon-free f / 2 medium 0h, 6h, 12h , 24h, 48h silicon limit, set f / 2 medium for the control group. The results showed that the silicon limit chlorophyll a and lutein, but on the fatty acid composition and percentage of significant. The silicon limit 6h EPA percentage of no change. Silicon limit 12h and 24h, EPA percentage of 20.96% and 21.86%, respectively, an increase of 9.85% and 17.72%, compared with the control group. The silicon limit of 48 h, the EPA percentage content decreased only 18.64%.
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