Lau Ming W, Dale Bruce E
Department of Chemical Engineering and Materials Science, Michigan State University, 3900 Collins Rd, Lansing, MI 48910, USA.
Proc Natl Acad Sci U S A. 2009 Feb 3;106(5):1368-73. doi: 10.1073/pnas.0812364106. Epub 2009 Jan 22.
Current technology using corn stover (CS) as feedstock, Ammonia Fiber Expansion (AFEX) as the pretreatment technology, and Saccharomyces cerevisiae 424A(LNH-ST) as the ethanologenic strain in Separate Hydrolysis and Fermentation was able to achieve 191.5 g EtOH/kg untreated CS, at an ethanol concentration of 40.0 g/L (5.1 vol/vol%) without washing of pretreated biomass, detoxification, or nutrient supplementation. Enzymatic hydrolysis at high solids loading was identified as the primary bottleneck affecting overall ethanol yield and titer. Degradation compounds in AFEX-pretreated biomass were shown to increase metabolic yield and specific ethanol production while decreasing the cell biomass generation. Nutrients inherently present in CS and those resulting from biomass processing are sufficient to support microbial growth during fermentation. This platform offers the potential to improve the economics of cellulosic ethanol production by reducing the costs associated with raw materials, process water, and capital equipment.
当前技术以玉米秸秆（CS）为原料，采用氨纤维膨胀（AFEX）作为预处理技术，并在分步水解发酵中使用酿酒酵母424A（LNH-ST）作为产乙醇菌株，在不洗涤预处理生物质、不进行解毒或不添加营养物质的情况下，乙醇浓度为40.0 g/L（5.1体积/体积%）时，能够实现每千克未处理CS产191.5 g乙醇。高固含量下的酶水解被确定为影响总乙醇产量和滴度的主要瓶颈。AFEX预处理生物质中的降解化合物被证明可提高代谢产量和特定乙醇产量，同时减少细胞生物质生成。CS中固有的营养物质以及生物质加工产生的营养物质足以支持发酵过程中的微生物生长。该平台具有通过降低与原材料、工艺用水和资本设备相关的成本来提高纤维素乙醇生产经济性的潜力。
