摘要
富含多不饱和脂肪酸的产油微藻是开发高值微藻油的理想原料,一株产油微藻是否具有高值油脂开发潜力需要评估其油脂产量、中性脂比例与多不饱和脂肪酸分布等指标。低氮胁迫是研究微藻油脂积累理想的方式之一,以一株产油绿球藻(Chlorococcum sp.)为实验材料,以硝酸钠(NaNO_3)为氮源,设置17.6 mmol/L、5.9 mmol/L和3.5 mmol/L三种氮浓度,跟踪测定产油绿球藻生长、脂类组成及多不饱和脂肪酸分布的时相变化。结果显示,3.5 mmol/L和5.9 mmol/L氮浓度条件下,产油绿球藻取得了2.55 g/L和2.51 g/L的总脂产量,远高于17.6 mmol/L氮浓度组的总脂产量(1.43 g/L);降低氮浓度可以提高中性脂比例,3.5mmol/L氮浓度组取得最高的中性脂比例,为88.6%总脂质(Total lipid,TL),高于5.9 mmol/L氮浓度组(86.3%TL)和17.6 mmol/L氮浓度组(80.5%TL);降低氮浓度可以改变产油绿球藻的脂肪酸在不同脂类分子中的分布,促进脂肪酸更多分布于中性脂中,其中,3.5 m mol/L TL氮浓度组培养结束时,α-亚麻酸在中性脂的比例由接种时的33.9%提高到86.5%。适宜氮浓度对于提高产油绿球藻总脂产量、中性脂比例而多不饱和脂肪酸分布具有重要作用,产油绿球藻积累的α-亚麻酸在低氮条件下更倾向于分布在中性脂中,是一株具有高值化微藻油开发价值的藻株。
Oleaginous microalga with rich polyunsaturated fatty acids（PUFAs）is considered an optimal raw material for the production of high-valued microalgae oil. The key screening indexes of high-valued microalgae include oil yield,neutral lipid fractionation,and PUFAsdistribution. Low-nitrogen stress is one of the most effective approaches in inducing oil accumulation in microalgae. The changes in growth,lipidcomposition,and PUFAs distribution of Chlorococcum sp. were determined under 17.6 mmol/L NaNO3,5.9 mmol/L NaNO3,and 3.5 mmol/L NaNO3. The results showed the total lipid yield reached 2.55 g/L and 2.51 g/L at 3.5 mmol/L and 5.9 mmol/L NaNO3 group,respectively,much higher than that 1.43 g/L at 17.6 mmol/L NaNO3 group. Lowering nitrogen concentration increased the proportion of neutral lipids,i.e.,itwas the highest at 3.5 mmol/L NaNO3,accounted for 88.6% in total lipid,higher than 86.3% at 5.9 mmol/L NaNO3,and 80.5% at 17.6 mmol/L NaNO3. Decreasing nitrogen concentration also changed the fatty acids distribution in different lipid fractionations and promoted the fattyacids more distributed in neutral lipids. For instance,at 3.5 mmol/L NaNO3,the proportion of α-linolenic acid in neutral lipids increased to86.5% at the end of the cultivation from 33.9% at the beginning of cultivation. Conclusively,appropriate nitrogen concentration has a great rolein the improvement of total oil yield,neutral lipid fractionation,and PUFAs distribution;moreover,the accumulated C18 ：3（ω-3）inChlorococcum sp. tends to be distributed in neutral lipids under low nitrogen,and thus Chlorococcum sp. is a potential oleaginous microalgae for the production of high-valued microalgae oil.
作者
李涛
许瑾
吴华莲
王铭
向文洲
LI Tao;XU Jin;WU Hua-lian;WANG Ming;XIANG Wen-zhou(Key Laboratory of Tropical MarineBio-resourcesand Ecology, South China Sealnstitute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301;Key Lab of Renewable Energy and Natural Gas Hydrate, Chinese Academy of Sciences, Guangzhou Institute of Energy Conversion, Chinese AcademyofSciences, Guangzhou 510640;School ofEco-EnvironmentalEngineering, Guizhou Minzu University, Guiyang 550025)
出处
《生物技术通报》
CAS
CSCD
北大核心
2018年第5期154-162,共9页
Biotechnology Bulletin
基金
中国科学院可再生能源重点实验室开放基金(Y607k91001)
贵州省教育厅青年科技人才成长项目(黔教合KY字[2016]160)
广东省自然科学基金-博士启动(2016A030310016)
广东省省级科技计划项目(2015A020216014)
广州市科技计划项目(201604016056)
关键词
产油绿球藻
微藻油
氮浓度
脂类组成
脂肪酸分布
oleaginous Chlorococcum sp.
microalgae oil
nitrogen concentration
lipid composition
fatty acids distribution
