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/商业潜力是以经济的方式生产下一代可持续、可再生、清洁燃烧、高能量密度、交通运输的生物燃料。拟议的技术一旦成功开发，将使现有的生物燃料生产商能够降低成本，同时增加其副产品的价值和多样性。它将把他们的工业废物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相互补充，它可能会使美国目前的生物柴油产量翻一番。国内227家乙醇工厂的规模从不到50加仑到超过1.5亿加仑不等，总年产能为150亿加仑。每加仑乙醇还会产生1.9磅的可溶性有机物，必须蒸发或处理。Xylome？S技术有潜力将其中一半转化为生物柴油，并利用纤维素原料进一步扩大生物柴油的生产。通过与发酵副产物一起转化更大比例的可溶性纤维素和半纤维素糖，Xylome将提高现有乙醇工厂的效率，并增加生物燃料的生产。这项第二阶段研究的目标是提高非传统产脂酵母的脂肪酸的生产、修饰和释放的速度。脂肪酸的能量密度比乙醇高得多，但比能量产率相似。将有机物发酵成脂类的效率可能相当于生产乙醇。在复制停止后，脂质通常在氮素限制条件下积累。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科学家识别并过度表达了在高氮条件下使脂肪积累增加1.2-2倍的基因。在第二阶段，他们将使用交配、选择、筛选和进化适应来结合这些修饰中的最好的。木质组科学家还瞄准了更多的基因来修饰和释放细胞中的脂肪酸。Xylome计划通过代谢工程从细胞水平优化脂肪生产，并通过生物工艺设计和培养条件从工程角度优化脂肪生产。Xylome还将使细胞快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会。

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.