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物转化为可用于制造生物柴油等燃料的脂肪酸。Xylome公司正在使用生物技术设计一种酵母平台，该平台将生产脂肪油。这将有助于将现有的生物燃料和生物质副产品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，这项技术可能会促进更高价值的第二代生物燃料的生产。S提出的技术每年可生产约120万加仑生物柴油。价值约400万美元，来自一家7000万加仑乙醇工厂的副产品。除了现有乙醇厂副产糖之外，Xylome？S技术平台还可以促进纤维素和半纤维素糖的脂肪酸生产，作为纤维素生物燃料生产的原料。这个第一阶段研究项目的第一个目标是在生长过程中能够产生脂肪。第二个将是缓解蜂窝容量限制。该项目将改变限制产量的基因的调控，并引入扩大产能的途径。当给予过量的碳和有限的氮时，酵母菌和真菌会合成脂肪，但在细胞生长过程中会出现低水平的脂肪合成。正常情况下，脂肪只有在细胞分裂停止后才会在细胞空泡中积累。这需要更长的培养时间，而且可以形成的脂类的数量受到细胞体积的限制。建议的方法将过度表达用于脂肪合成的酶，以便工程细胞在生长过程中产生石油，同时保持高水平的代谢活动。将引入新的途径以及能够实现连续脂质回收的过程。这些改进应该能够a)在连续的高密度培养中产生脂肪，从而克服固有的低脂肪合成率，以及b)连续分离脂肪，从而减少对细胞采集、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.