c/o Lakeshore Engineering Services, U.S. EPA Test and Evaluation Facility, 1600 Gest Street, Cincinnati, OH 45204, USA.
Bioresour Technol. 2010 Feb;101(4):1277-84. doi: 10.1016/j.biortech.2009.09.042. Epub 2009 Oct 6.
Multi-stage continuous (chemostat) culture fermentation (MCCF) with variable fermentor volumes was carried out to study the utilization of glucose and xylose for ethanol production via mixed sugar fermentation (MSF). Variable fermentor volumes were used to enable enhanced sugar utilization, accounting for differences in glucose and xylose utilization rates. Saccharomyces cerevisiae 424A-LNH-ST was used for fermentation of glucose-xylose mixtures. The dilution rates employed for continuous fermentation were based on earlier batch kinetic studies of ethanol production and sugar utilization. With a feed containing approximately 30 g L(-1) glucose and 15 g L(-1) xylose, cell washout was observed at a dilution rate of 0.8 h(-1). At dilution rates below 0.5 h(-1), complete glucose utilization was observed. Xylose consumption in the first-stage 1 L reactor was only 37% at the lowest dilution rate studied, 0.0 5h(-1). At this same flow rate, xylose consumption rose to 69% after subsequently passing through 3 and 1 L reactors in series, primarily due to the longer residence time in the 3 L reactor (0.0167 h(-1) dilution rate).
采用多阶段连续（恒化器）培养发酵（MCCF）并改变发酵罐体积，以研究通过混合糖发酵（MSF）利用葡萄糖和木糖生产乙醇。改变发酵罐体积可提高糖的利用率，从而弥补葡萄糖和木糖利用率的差异。采用酿酒酵母 424A-LNH-ST 发酵葡萄糖-木糖混合物。连续发酵的稀释率基于先前的乙醇生产和糖利用分批动力学研究。以含有约 30 g L(-1)葡萄糖和 15 g L(-1)木糖的进料进行发酵，在稀释率为 0.8 h(-1)时观察到细胞洗出。在低于 0.5 h(-1)的稀释率下，观察到完全利用葡萄糖。在研究的最低稀释率 0.05 h(-1)下，1 L 第一阶段反应器中木糖的消耗仅为 37%。在相同的流速下，木糖的消耗在随后通过串联的 3 和 1 L 反应器时增加到 69%，这主要是由于在 3 L 反应器中的停留时间更长（0.0167 h(-1)稀释率）。
