低氮胁迫对两种魏氏藻生长和油脂积累的影响

The effects of low-nitrogen stress on the growth and lipid accumulation of Vischeria helvetica and Vischeria punctata

为了评价低氮胁迫对真眼点藻纲的两株高产油微藻(斧形魏氏藻和点状魏氏藻)的生长和油脂积累的影响,实验设计中将原改良BG-11培养基中的硝酸钠浓度降低为3.6 mmol/L(0.3 g/L)。结果表明:在此浓度下斧形魏氏藻和点状魏氏藻的最高生物量分别为8.21 g/L和9.07 g/L;两者的总脂、中性脂和总脂肪酸含量(占干重)都随着培养时间的延长而不断增加,培养至第18天时分别达到56.4%,64.7%;54%,63.3%;43.5%,45.5%。这两种微藻的主要脂肪酸都含有豆蔻酸、棕榈酸、棕榈油酸、油酸、亚油酸、花生四烯酸和二十碳五烯酸,均适合于生物柴油的生产。它们的总脂、中性脂和总脂肪酸的单位体积产率分别为0.257 g/(L·d),0.326 g/(L·d);0.246 g/(L·d),0.319 g/(L·d)和0.198 g/(L·d),0.229 g/(L·d)。这说明两种微藻在低氮胁迫下都能够获得较高的油脂产率。

In order to evaluating the effects of low-nitrogen stress on the growth and lipid accumulation of two oleaginous Eutigmatophyceae microalgae Vischeria helvetica and Vischeria punctata, the initial nitrate concentration of modified BG-11 medium was reduced to 3.6 mmol/L（0.3 g/L）.The results showed that the highest biomass concentration of V. helvetica and V. punctata under this low level of nitrate were up to 8.21 g/L and 9.07 g/L, respectively. The contents of total lipids（TLs）, neutral lipids（NLs）and total fatty acids（TFAs）（on the basis of dry weight） of both microalgae gradually increased along with the culturing time, their highest contents separately reached 56.4%, 64.7%;54%, 63.3%; 43.5% and 45.5%.The volumetric productivities of TLs, NLs and TFAs in these two microalgae achieved 0.257 g/（L·d）,0.326 g/（L·d）;0.246 g/（L·d）,0.319 g/（L·d）;0.198 g/（L·d） and 0.229 g/（L·d）, respectively. The fatty acids profiles in the two microalgae were composed of myristic acid, palmitic acid, palmitoleic acid, oleic acid linoleic acid, arachidonic acid and eicosapentaenoic acid, which could be used as the feedstocks of biodiesel. Those results indicated that V. helvetica and V. punctata are both potential species for biodiesel production.