Challenges in enzymatic hydrolysis and fermentation of pretreated Arundo donax revealed by a comparison between SHF and SSF
Challenges in enzymatic hydrolysis and fermentation of pretreated Arundo donax revealed by a comparison between SHF and SSF
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DOI：
10.1016/j.procbio.2012.05.016
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发表时间：
2012-10-01
影响因子：
4.4
通讯作者：
Olsson, Lisbeth
中科院分区：
文献类型：
--
作者：
Ask, Magnus;Olofsson, Kim;Olsson, Lisbeth
多年生草本作物龙竹是生产第二代生物乙醇的潜在原料。在本工作中，研究了两种不同的工艺选择，以转化两种不同的蒸汽预处理批次的唐菖蒲。采用分离水解发酵（SHF）或同时糖化发酵（SSF）两种方法，利用一株消耗木糖的酿酒酵母菌VTT C-10880将预处理后的原料转化为乙醇。使用SHF可获得最高的总乙醇收率和最终乙醇浓度（0.27 g g（-1）和20.6 g L-1，而使用SSF时为0.24 g g（-1）和19.0 g L-1）。用半纤维素酶补充纤维素水解酶，提高了SHF和SSF的性能。其中一个批次中较高的乙酸量对发酵过程中木糖的消耗有强烈的影响。第1批（高乙酸）发酵时木糖只消耗了一半，而第2批（低乙酸）发酵时木糖消耗了94%。此外，预处理材料中存在的大量低聚木显著抑制了酶解。因此，在预处理过程中需要同时考虑木糖低聚物和乙酸的形成，以实现唐芦草向乙醇的有效转化。(c) 2012 Elsevier Ltd.版权所有。
The perennial herbaceous crop Arundo donax is a potential feedstock for second-generation bioethanol production. In the present work, two different process options were investigated for the conversion of two differently steam-pretreated batches of A. donax. The pretreated raw material was converted to ethanol with a xylose-consuming Saccharomyces cerevisiae strain, VTT C-10880, by applying either separate hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF). The highest overall ethanol yield and final ethanol concentration were achieved using SHF (0.27 g g(-1) and 20.6 g L-1 compared to 0.24 g g(-1) and 19.0 g L-1 when SSF was used). The performance of both SHF and SSF was improved by complementing the cellulolytic enzymes with hemicellulases. The higher amount of acetic acid in one of the batches was shown to strongly affect xylose consumption in the fermentation. Only half of the xylose was consumed when batch 1 (high acetic acid) was fermented, compared to that 94% of the xylose was consumed in fermentation of batch 2 (lower acetic acid). Furthermore, the high amount of xylooligomers present in the pretreated materials considerably inhibited the enzymatic hydrolysis. Both the formation of xylooligomers and acetic acid thus need to be considered in the pretreatment process in order to achieve efficient conversion of A. donax to ethanol. (c) 2012 Elsevier Ltd. All rights reserved.