暨南大学李宏业课题组发表脂类代谢最新研究成果

2016年6月23日，国际代谢工程领域顶级研究期刊《Metabolic Engineering》在线发表了暨南大学生命科学技术学院李宏业教授发表的微藻脂类物质代谢研究成果，李宏业教授为通讯作者。

激光共聚焦显微镜下成像。A) 工程藻细胞; B) 野生藻细胞。

微藻的脂类物质含量及组成直接影响着微藻在水产、营养保健、生物能源等领域的应用，是微藻资源高值化利用中的重要评价指标。由于藻类独特的生存环境造成其代谢途径及代谢物成分与陆生生物有很大不同，基因组情况复杂，研究困难。对微藻脂类合成的调控机制的认知不足，使得微藻藻株改良研究的进展缓慢。

生科院李宏业教授课题组围绕微藻脂类物质合成与累积开展了研究，在IF：8.2)发表论文，报道了产油微藻代谢工程调控的关键节点。课题组构建了典型产油微藻三角褐指藻的遗传转化体系，对其脂质代谢网络潜在关键节点进行了挖掘，发现了一种新型的定位于线粒体的苹果酸脱氢酶，具有很强的促NADPH生成的作用，可提供胞内丰富的还原力，促进脂肪酸的合成。基于这一发现，成功获得显著上调表达该酶的工程藻株，工程藻株的生长速率与野生型藻类似，而藻细胞显著增大，中性脂含量提高达2.5倍，从干重的23.3%提高到突破性的57%。工程藻株在保持高生物量的同时，获得了高脂质含量，综合性状优于已报道的产油微藻。研究结果也表明了微藻的脂质累积具有其独特的机制，丰富了对脂类代谢的认知。研究成果得到了国内外同行的高度关注，文章发表后被scienceDirect评为当季下载量最多文章之一“The most downloaded articles from ScienceDirect in the last 90 days”。

原文链接：

http://www.sciencedirect.com/science/article/pii/S1096717614001244

genetic improvement of the microalga Phaeodactylum tricornutum for boosting neutral lipid accumulation

原文摘要：

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 tricornutumME (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.