Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou 510632, China.
Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou 510632, China.
Metab Eng. 2015 Jan;27:1-9. doi: 10.1016/j.ymben.2014.10.002. Epub 2014 Oct 24.
To obtain fast growing oil-rich microalgal strains has been urgently demanded for microalgal biofuel. Malic enzyme (ME), which is involved in pyruvate metabolism and carbon fixation, was first characterized in microalgae here. Overexpression of Phaeodactylum tricornutum ME (PtME) significantly enhanced the expression of PtME and its enzymatic activity in transgenic P. tricornutum. The total lipid content in transgenic cells markedly increased by 2.5-fold and reached a record 57.8% of dry cell weight with a similar growth rate to wild type, thus keeping a high biomass. The neutral lipid content was further increased by 31% under nitrogen-deprivation treatment, still 66% higher than that of wild type. Transgenic microalgae cells exhibited obvious morphological changes, as the cells were shorter and thicker and contained larger oil bodies. Immuno-electron microscopy targeted PtME to the mitochondrion. This study markedly increased the oil content in microalgae, suggesting a new route for developing ideal microalgal strains for industrial biodiesel production.
为了生产富含油脂的微藻生物燃料，人们迫切需要快速生长的微藻品系。本文首次对微藻中的苹果酸酶（Malic enzyme，ME）进行了特征描述，该酶参与丙酮酸代谢和碳固定。过表达三角褐指藻 ME（Phaeodactylum tricornutum ME，PtME）显著提高了转基因三角褐指藻中 PtME 的表达及其酶活性。与野生型相比，转基因细胞的总脂含量显著增加了 2.5 倍，达到了干重的 57.8%，同时保持了较高的生物量。在氮饥饿处理下，中性脂含量进一步增加了 31%，仍比野生型高出 66%。转基因微藻细胞表现出明显的形态变化，细胞更短、更厚，并且含有更大的油体。免疫电子显微镜将 PtME 靶向定位于线粒体。本研究显著提高了微藻中的油脂含量，为开发理想的工业生物柴油生产用微藻品系提供了新途径。
