SBIR Phase II: Novel Bioprocess for Lipid Production from Industrial Byproducts

这个小企业创新研究第二阶段项目的更广泛的影响/商业潜力是经济地生产下一代可持续的、可再生的、清洁燃烧的、高能量密度的运输生物燃料。拟议中的技术一旦开发成功，将使现有的生物燃料生产商能够降低成本，同时增加副产品的价值和多样性。它将把他们的工业废料转化为适合生物柴油的定制脂肪酸。这项技术将与纤维素乙醇生产商兼容并互补，它有可能使美国目前生产的生物柴油的数量增加一倍。227家国内乙醇工厂的规模从不足5000万加仑到超过1.5亿加仑不等，它们的年总产能为150亿加仑。每加仑乙醇还会产生1.9磅的可溶性有机物，这些有机物必须蒸发或处理掉。Xylome吗?S技术有潜力将这一流程的一半转化为生物柴油，并进一步扩大纤维素原料的生物柴油生产。通过转化更大比例的可溶性纤维素和半纤维素糖以及发酵副产品，Xylome将提高现有乙醇工厂的效率并增加生物燃料的产量。本二期研究的目的是提高非常规脂肪酵母脂肪酸的生产、修饰和释放速度。脂肪酸的能量密度比乙醇高得多，但比能产率相似。有机物发酵成脂质的效率可能与乙醇生产相当。在复制停止后，脂质通常在氮限制条件下积累。它们不会从细胞中排出，因此回收不需要蒸馏。在第一阶段，Xylome科学家发现并过度表达了高氮条件下使脂质积累增加1.2- 2倍的基因。在第二阶段，它们将通过交配、选择、筛选和进化适应来结合这些变化的最佳效果。木质部科学家还瞄准了其他基因来修饰和释放细胞中的脂肪酸。Xylome计划从细胞水平上通过代谢工程和从工程角度通过生物工艺设计和培养条件来优化脂质生产。Xylome还将改造细胞，使其迅速利用可溶性低聚糖、半纤维素糖和发酵副产物的复杂混合物。通过应用先进的分子技术和合成生物学，Xylome将为可持续生物燃料生产开辟新的机遇。

The broader impact/commercial potential of this Small Business Innovation Research Phase II Project is to produce economically the next generation of sustainable, renewable, clean burning, high energy density, transportation biofuels. The proposed technology once successfully developed will enable existing biofuel producers to reduce their costs while increasing the value and diversity of their byproducts. It will convert their industrial waste products into tailored fatty acids suitable for biodiesel. The technology will be compatible with and complementary to cellulosic ethanol producers, and it could potentially double the amount of biodiesel produced in the U.S. today. The 227 domestic ethanol plants range in size from less than 50 to more than 150 million gallons, and they have a total annual capacity of 15 billion gallons. Every gallon of ethanol also yields 1.9 pounds of soluble organics that must be evaporated or disposed. Xylome?s technology has the potential to convert half of this stream into biodiesel and to expand biodiesel production further with cellulosic feedstocks. By converting a larger fraction of the soluble cellulosic and hemicellulosic sugars along with fermentation byproducts, Xylome will increase the efficiency of existing ethanol plants and increase biofuel production.The objectives of this Phase II research are to increase the rates of production, modification and release of fatty acids from non-conventional lipogenic yeast. Fatty acids have much higher energy density than ethanol, but similar specific energy yields. Fermentation of organics to lipids can potentially occur with efficiencies equivalent to ethanol production. Lipids normally accumulate under nitrogen limiting conditions after replication has stopped. They are not excreted from the cells so recovery does not require distillation. In Phase I, Xylome scientists identified and over expressed genes that increase lipid accumulation by 1.2- to 2-fold under high nitrogen conditions. In Phase II, they will use mating, selection, screening and evolutionary adaptation to combine the best of these modifications. Xylome scientists have also targeted additional genes to modify and release fatty acids from the cell. Xylome plans to optimize lipid production both from a cellular level with metabolic engineering and from an engineering perspective through bioprocess design and cultivation conditions. Xylome will also engineer cells to use rapidly the complex mixture of soluble oligosaccharides, hemicellulosic sugars and fermentation byproducts. By applying advanced molecular techniques and synthetic biology, Xylome will open up new opportunities for sustainable biofuel production.