Production of isoprenoid-based biofuel in algae using a synthetic biology approach

世界面临着巨大的挑战，即以生物燃料等清洁能源技术为基础的经济补充并最终取代以化石燃料为基础的经济。目前，商业上可获得的生物燃料（例如生物乙醇和生物柴油）来源于作物植物，例如玉米和大豆。然而，人们对使用宝贵的农业土地生产生物燃料作物以及这种技术的可持续性和能源平衡都感到严重关切。一种潜在的生物燃料替代来源是微藻-一种水生光合生物，不需要肥沃的土地来种植;生长速度比植物快得多，并且可以积累大量的高能量化合物，如油。此外，这种水产养殖可以与工业产生的二氧化碳和富含营养物的废水等废物流结合起来，从而利用这些废物促进藻类生长。然而，用于生物燃料的微藻的工业规模培养面临相当大的挑战，不仅在技术可行性方面，而且在经济性和实现净正能量平衡方面。人们认识到，成功将可能需要开发上级藻类菌株，其中基因工程方法已被用于从根本上改变和调整细胞代谢，使其在工业条件下达到最大的生物燃料生产率。目前，创造这种菌株所需的分子工具有限，藻类代谢工程仍处于起步阶段。在这个项目中，我们将沿着目前用于设计和创造新的细菌和酵母菌株的“合成生物学”技术路线，开发先进的藻类工具。我们的方法的一个特别有吸引力的特征是，我们将利用将新基因引入两个独立的遗传隔间（细胞核和叶绿体）的能力，从而允许采用多个新基因并在叶绿体内创建新的生物合成途径的工程设计策略，但可以从细胞核进行调节。我们将通过创造一系列设计藻类来验证这项新技术，这些藻类可以产生两种潜在的有用燃料分子-短链烃，异戊二烯和酒精，香叶醇。

The World is faced with the considerable challenge of supplementing, and ultimately replacing, its fossil fuel-based economy with one based on clean energy technologies such as biofuels. Currently, commercially available biofuels (e.g. bioethanol and biodiesel) are derived from crop plants such as maize and soybean. However, there are major concerns regarding both the use of valuable agricultural land for production of biofuel crops, and the sustainability and energy balance of such technologies. A potential alternative source of biofuels is microalgae - aquatic photosynthetic organisms that do not require fertile land for cultivation; grow considerably faster than plants, and which can accumulate significant quantities of high-energy compounds such as oils. Furthermore, such aquatic cultivation could be coupled to waste streams such as CO2 output from industry and nutrient-rich effluent, thereby using this waste to promote algal growth. However, industrial-scale cultivation of microalgae for biofuels faces considerable challenges, not just in terms of technical feasibility, but also in terms of the economics and achieving a net positive energy balance. It is recognised that success will probably require the development of superior algal strains in which genetic engineering methods have been used to radically alter and tailor the cell metabolism's towards maximal biofuel productivity under industrial conditions. Currently, the molecular tools needed to create such strains are decided limited and algal metabolic engineering is still in its infancy. In this project, we will develop advanced tools for algae along the lines of the 'synthetic biology' technology now being used to design and create novel bacterial and yeast strains. A particularly, attractive feature of our approach is that we will exploit the ability to introduce new genes into two separate genetic compartments, the nucleus and the chloroplast, thereby allowing elaborate strategies for engineering that employ multiple new genes and create novel biosynthetic pathways within the chloroplast, but which can regulated from the nucleus. We will validate this new technology by creating a series of designer algae that produce two potentially useful fuel molecules - the short-chain hydrocarbon, isoprene and the alcohol, geraniol.