Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA 50011, USA.
Bioresour Technol. 2010 Aug;101(15):5910-6. doi: 10.1016/j.biortech.2010.03.015. Epub 2010 Mar 24.
An integrated bioconversion process was developed to convert corn stover derived pentose and hexose to ethanol effectively. In this study, corn stover was pretreated by soaking in aqueous ammonia (SAA), which retained glucan ( approximately 100%) and xylan (>80%) in the solids. The pretreated carbohydrates-rich corn stover was converted to ethanol via two-phase simultaneous saccharification and fermentation (TPSSF). This single-reactor process employed sequential simultaneous saccharification and fermentation (SSF), i.e. pentose conversion using recombinant Escherichia coli KO11 in the first phase, followed by hexose conversion with Saccharomyces cerevisiae D5A in the second phase. In the first phase, 88% of xylan digestibility was achieved through the synergistic action of xylanase and endo-glucanase with minimal glucan hydrolysis (10.5%). Overall, the TPSSF using 12-h SAA-treated corn stover resulted in the highest ethanol concentration (22.3g/L), which was equivalent to 84% of the theoretical ethanol yield based on the total carbohydrates (glucan+xylan) in the untreated corn stover.
开发了一种集成的生物转化工艺，可有效地将玉米秸秆中的戊糖和己糖转化为乙醇。在本研究中，采用氨水溶液（SAA）对玉米秸秆进行预处理，使固相中保留了约 100%的葡聚糖和大于 80%的木聚糖。预处理后的富含碳水化合物的玉米秸秆通过两相同步糖化发酵（TPSSF）转化为乙醇。该单反应器工艺采用顺序同步糖化发酵（SSF），即在第一阶段使用重组大肠杆菌 KO11 转化戊糖，然后在第二阶段使用酿酒酵母 D5A 转化己糖。在第一阶段，木聚糖酶和内切葡聚糖酶的协同作用使木聚糖的消化率达到 88%，而葡聚糖的水解率最低（10.5%）。总体而言，使用 12 小时 SAA 处理的玉米秸秆进行的 TPSSF 产生了最高的乙醇浓度（22.3g/L），相当于未处理玉米秸秆中总碳水化合物（葡聚糖+木聚糖）理论乙醇产量的 84%。
