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

这个小企业创新研究第一阶段项目的更广泛的影响和商业潜力将是使糖能够生化转化为脂肪酸，可用于制造生物柴油等燃料。Xylome公司正在利用生物技术设计一种生产脂肪油的酵母平台。这将促进现有生物燃料和生物质副产物流转化为有用的商业脂肪酸，同时降低加工成本。脂肪酸的生产将促进最初下游目标生物柴油的生产，但从长远来看，该技术可以提高更高价值的第二代生物燃料的生产。 Xylome？公司提出的技术每年可生产约120万加仑生物柴油。一个7000万加仑乙醇工厂的副产品价值约400万美元。除了现有乙醇工厂的副产品中的糖，Xylome？的技术平台可以促进从纤维素和半纤维素糖生产脂肪酸，作为纤维素生物燃料生产的原料。第一阶段研究项目的第一个目标是在生长过程中实现脂质生产。第二个是缓解蜂窝容量限制。该项目将改变限制产量的基因调控，并引入扩大产量的途径。酵母和真菌在给予过量的碳和有限的氮时合成脂质，但在细胞生长期间发生低水平的脂质合成。正常情况下，脂质仅在细胞分裂停止后积聚在细胞空泡中。这需要延长培养时间，并且可以形成的脂质的量受到细胞体积的限制。所提出的方法将过表达用于脂质合成的酶，使得工程细胞在生长期间产生油，同时保持高水平的代谢活性。新的途径将被引入沿着的过程，将使连续的脂质回收。这些修饰应该能够实现a）在连续高密度培养中的脂质生产，从而克服脂质合成的固有低速率，和B）脂质的连续分离，从而减轻对细胞收获、破裂和提取的需要。

The broader impact and commercial potential of this Small Business Innovation Research Phase I project will be to enable the biochemical conversion of sugars into fatty acids that can be used to make fuels such as biodiesel. Xylome Corporation is using biotechnology to engineer a yeast platform that will produce fatty oils. This will facilitate conversion of existing biofuel and biomass byproduct streams into useful commercial fatty acids while reducing processing costs. The production of fatty acids will facilitate production of the initial downstream target which is biodiesel, but longer term, the technology could enhance production of higher value second-generation biofuels. Xylome?s proposed technology could produce approximately 1.2 million gallons of biodiesel/yr. worth about $4 million from the byproducts of a single 70 million gallon ethanol plant. Beyond sugars from byproduct streams of existing ethanol plants, Xylome?s technology platform could facilitate fatty acid production from cellulosic and hemicellulosic sugars serving as a feedstock for cellulosic biofuel production. The first objective of this Phase I research project is to enable lipid production during growth. The second will be to relieve cellular capacity constraints. The project will alter regulation of genes that limit production and introduce pathways that expand capacity. Yeasts, and fungi synthesize lipid when given excess carbon and limiting nitrogen, but low levels of lipid synthesis occurs during cell growth. Normally lipid only accumulates in cellular vacuoles after cell division has stopped. This requires extended cultivation times, and the amount of lipid that can be formed is constrained by the cell volume. The proposed approach will overexpress the enzymes for lipid synthesis so that the engineered cells will produce oil during growth while maintaining high levels of metabolic activity. New pathways will be introduced along with processes that will enable continuous lipid recovery. These modifications should enable a) lipid production in continuous high-density culture, thereby overcoming inherent low rates of lipid synthesis, and b) continuous separation of lipid, thereby alleviating the need for cell harvest, rupture and extraction.