培养基初始pH值和照射光波长对杜氏藻中类胡萝卜素含量的影响

研究杜氏藻在实验室培养过程中初始pH值和照射光波长对其体内类胡萝卜素（β-胡萝卜素和叶黄素）积累的影响。在实验中，配制不同初始pH值的培养基，用其培养105 d，测定培养液中藻细胞数和β-胡萝卜素及叶黄素的含量。用pH 7的培养基，在白光（全波）、红光（630 nm）和蓝光（430 nm）照射下培养藻40 d，测定培养液中藻细胞数和β-胡萝卜素、叶黄素的含量。结果表明：1）杜氏藻本身具有调节环境pH值向中性发生变化的能力。培养105 d后，不同初始pH值范围的培养液（pH 10～13、pH 1～3和pH 4～9）中藻养殖密度依次增加。初始pH 4时，培养液中藻细胞数量可达1 851 个/mL，达到最大值；初始pH值范围为7～9时，培养液中β-胡萝卜素（0.489～0.561 mg/mL）和叶黄素（0.610～0.700 mg/mL）积累量较高；初始pH值范围为11～13时，单个细胞内β-胡萝卜素（0.603～0.730 ng）和叶黄素（0.897～0.979 ng）积累量较高。2）杜氏藻养殖密度在全波光、红光（630 nm）和蓝光（430 nm）条件下均可增加。红光和蓝光均可诱导单个细胞中β-胡萝卜素和叶黄素积累量增加，蓝光效果最佳，单个细胞中叶黄素含量达到0.524 ng，β-胡萝卜素含量达到0.589 ng。

Effects of Culture Medium pH and Illumination Wavelength on Carotenoid Content of Dunaliella salina

This study aims to explore the effects of initial pH of culture medium and different illumination wavelengths on
the contents of carotenoids including β-carotene and lutein from Dunaliella salina during culture. In experiments, media
with different pH values were prepared and used to culture Dunaliella salina for 105 days. Under the illumination of white
(full wavelengths), red (630 nm) and blue light (430 nm), medium with pH 7 was applied to culture Dunaliella salina for
40 days. Dunaliella salina culture density was then determined while β-carotene and lutein contents were assessed from
culture liquid. Data obtained from the experiments suggested that: 1) Dunaliella salina was able to adjust the environmental
pH to neutral. After 105-day culture, an increased Dunaliella salina culture density was observed from culture liquids with
original pH 10–13, pH 1–3 and pH 4–9 while the maximum Dunaliella salina culture density was counted at pH 4 (1 851 cell
counts/mL). Higher β-carotene (0.489-0.561 mg/mL) and lutein (0.610-0.700 mg/mL) contents were observed from culture liquids
with original medium pH 7–9, while higher β-carotene (0.603-0.730 ng) and lutein (0.897-0.979 ng) contents were seen from
single cells with original medium pH 11-13; 2) Dunaliella salina culture density could increase under illumination at the full-range
wavelength, red (630 nm) and blue light (430 nm) after 40-day culture. Both red and blue lights were able to induce increased
contents of β-carotene (0.589 ng) and lutein (0.524 ng) from single cells while blue light was the most effective.