乙酸钠诱导雨生红球藻合成虾青素的机理

Inducing Mechanism of Acetate on Astaxanthin Synthesis in Haematococcus pluvialis

添加乙酸钠时,雨生红球藻细胞内硝酸还原酶(NR)的活性提高了1.6倍,培养液中硝酸盐浓度的迅速下降。另一方面,乙酸钠的存在和氮缺乏,又抑制了叶绿素的合成和1,5-二磷酸核酮糖羧化酶(Rubisco)的活性。在虾青素开始合成的第4d,硝酸盐的浓度,叶绿素含量和Rubisco活性分别下降了96.7%,71.9%和80%。相比之下,在未添加乙酸钠的对照培养液中,实验结束时硝酸盐的浓度,叶绿素含量和Rubisco活性仅下降了47.2%,27.3%和4.4%,培养过程中没有虾青素积累。

Nitrate reductase （NR） increased 1.6 folds in the acetate-added culture of Haematococcus pluvialis. Consequently, the algal cells absorbed nitrate quickly for heterotrophic growth, leading to ultimately short supply of nitrogen, which in turn inhibited the formation of chlorophyll and the activity of ribulose-1, 5-bisphosphate carboxylase （Rubisco） . When astaxanthin synthesis was triggered on the fourth day, nitrate concentration, chlorophyll content and Rubisco activity reduced by 96. 7%, 71.9% and 80%, respectively. By contrast, in the culture without acetate, chlorophyll content and Rubisco activity decreased only 47.2%, 27.3% and 4. 4% at the end of the experiment with no astaxanthin accumulated.