Kim Tae Hyun, Nghiem Nhuan P, Hicks Kevin B
Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA, USA.
Appl Biochem Biotechnol. 2009 May;153(1-3):171-9. doi: 10.1007/s12010-009-8524-0. Epub 2009 Jan 29.
A new process for pretreatment of lignocellulosic biomass, designated the soaking in ethanol and aqueous ammonia (SEAA) process, was developed to improve hemicellulose preservation in solid form. In the SEAA process, an aqueous ammonia solution containing ethanol is used. Corn stover was treated with 15 wt.% ammonia at 1:9 solid-liquid ratio (by weight) at 60 degrees C for 24 h with ethanol added at 1, 5, 20, and 49 wt.% (balance was water). The extents by which xylan was solubilized with no ethanol and with ethanol added at 1, 5, 20, and 49 wt.% of the total liquid were 17.2%, 16.7%, 14.5%, 10.4%, and 6.3% of the original xylan, respectively. Thus, at the highest ethanol concentration used the loss of hemicellulose to the liquid phase was reduced by 63%. The digestibility of glucan and xylan in the pretreated corn stover samples by cellulase was not affected by ethanol addition of up to 20 wt.%. The enzymatic digestibility of the corn stover treated with 49 wt.% ethanol added was lower than the digestibility of the sample treated with no ethanol addition. Thus, based on these results, 20 wt.% was found to be the optimum ethanol concentration for use in the SEAA process for pretreatment of corn stover.
为了提高半纤维素以固体形式的保留率，开发了一种木质纤维素生物质预处理的新工艺，称为乙醇氨水溶液浸泡（SEAA）工艺。在SEAA工艺中，使用含有乙醇的氨水溶液。以1:9的固液比（按重量计），在60℃下用15 wt.%的氨处理玉米秸秆24小时，并分别添加1 wt.%、5 wt.%、20 wt.%和49 wt.%（其余为水）的乙醇。在不添加乙醇以及添加1 wt.%、5 wt.%、20 wt.%和49 wt.%乙醇的情况下，木聚糖溶解的程度分别为原始木聚糖的17.2%、16.7%、14.5%、10.4%和6.3%。因此，在使用的最高乙醇浓度下，液相中半纤维素的损失减少了63%。添加高达20 wt.%的乙醇对预处理后的玉米秸秆样品中葡聚糖和木聚糖的纤维素酶消化率没有影响。添加49 wt.%乙醇处理的玉米秸秆的酶消化率低于未添加乙醇处理的样品的消化率。因此，基于这些结果，发现20 wt.%是用于玉米秸秆预处理的SEAA工艺的最佳乙醇浓度。
