Development of Renewable Biofuels Technology by Transcriptomic Analysis and Metabolic Engineering of Diatoms

0903712希尔德布兰德该奖项是根据2009年美国复苏和再投资法案资助的（公法111-5）。该项目的目标是开发硅藻的代谢工程方法，以通过可控地操纵细胞内过程而不是外部环境条件来诱导脂质积累，并操纵细胞内脂质和碳水化合物合成之间的碳分配，以使丰富的生物质和脂质积累成为可能。有四个具体目标：1）进行比较转录组学分析硅藻的脂质积累硅，氮，硒限制，以确定关键的调控步骤参与控制脂质积累和碳分配。2)通过简单的操作对硅藻细胞进行代谢工程改造，以抑制硅的运输，作为人为地使细胞缺乏硅以触发脂质积累的手段。3)通过简单的操作对细胞进行代谢工程改造，以抑制硝酸盐转运，作为人为地使细胞缺乏氮以触发脂质积累的手段。4)对细胞进行代谢工程改造，以改变碳分配，从而使丰富的脂质积累沿着高生物量生产，而不需要营养限制。智力优势：该项目的重要性在于，它将通过使用可操纵的细胞内过程而不是依赖于可变的环境条件来更好地控制用于生物燃料生产的硅藻中的脂质积累，并且它可能在正常生长条件下实现脂质积累。在微藻中，脂质积累通常发生在营养限制条件下，其受到环境变化的影响，并且其防止高生物量积累。将脂质诱导的控制转移到细胞内过程将消除可变性，并且确定与代谢工程结合的细胞中控制碳分配所涉及的关键调控步骤应该能够在非限制性营养生长条件下将碳更大地分配到脂质中。预计这些方法将对可再生生物燃料技术的发展产生重大影响。更广泛的影响：本科生和高中生参与该项目将使他们能够体验“动手”实验室研究。这对年轻人的心智发展至关重要，能够欣赏发现的实际和动态方面，而不仅仅是通过讲座或阅读吸收信息。这一点的重要性怎么强调都不过分，因为它培养了对努力和承诺水平的欣赏，而这些努力和承诺必须应用于任何成功的奋进。这些学生将参加当地的培训计划，强调代表性不足的少数民族的参与。拟议研究的社会效益将通过开发硅藻作为可再生燃料来源的技术应用来实现。潜在的好处包括减少二氧化碳的产生和随后对气候变化的好处，减少对石油进口的依赖，以及在这一新兴技术行业创造新的就业机会。

0903712 HildebrandThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The goal of this project is to develop metabolic engineering approaches for diatoms to enable induction of lipid accumulation by controllable manipulation of intracellular processes rather than from external environmental conditions, and to manipulate carbon partitioning within the cell between lipid and carbohydrate synthesis to enable both abundant biomass and lipid accumulation. There are four specific objectives: 1) To perform comparative transcriptomic analyses in diatoms of lipid accumulation resulting from silicon, nitrogen, and selenium limitation, to identify key regulatory steps involved in controlling lipid accumulation and carbon partitioning. 2) To metabolically engineer the diatom cell to enable repression of silicon transport by simple manipulations, as a means to artificially starve the cells for silicon to trigger lipid accumulation. 3) To metabolically engineer the cell to enable repression of nitrate transport by simple manipulations, as a means to artificially starve the cells for nitrogen to trigger lipid accumulation. 4) To metabolically engineer the cell to alter carbon partitioning to enable abundant lipid accumulation along with high biomass production, without the need for nutrient limitation. Intellectual Merit: The significance of this project is that it will enable greater control over lipid accumulation in diatoms for biofuels production by using manipulable intracellular processes rather than depending on variable environmental conditions, and it will possibly enable lipid accumulation under normal growth conditions. In microalgae, lipid accumulation generally occurs under nutrient limiting conditions, which are subject to environmental variability, and which prevents high biomass accumulation. Transferring control of lipid induction to intracellular processes will eliminate the variability, and identifying the key regulatory steps involved in controlling carbon partitioning in the cell coupled with metabolic engineering should enable greater partitioning of carbon into lipids during non-limiting nutrient growth conditions. These approaches are expected to have a substantial impact on the development of renewable biofuels technology. Broader Impact: The involvement of undergraduate and high school students in this project will enable them to experience "hands on" laboratory research. This is critical in the development of a young person's mind, to be able to appreciate the practical and dynamic aspects of discovery, as apposed to just assimilating information via lectures or reading. This importance of this cannot be overemphasized, because it develops an appreciation for the level of effort and commitment that must be applied to any successful endeavor. The students will participate as part of local training programs that emphasize the involvement of underrepresented minorities. The societal benefits of the proposed research will be realized through the technological application of developing diatoms as a source of renewable fuels. The potential benefits include reduced CO2 production and subsequent benefit to climate change, decreased dependence on oil imports, and establishment of new jobs in this emerging technology industry.