Enhancing the Enzymatic Hydrolysis of Lignocellulosic Biomass by Increasing the Carboxylic Acid Content of the Associated Lignin
Enhancing the Enzymatic Hydrolysis of Lignocellulosic Biomass by Increasing the Carboxylic Acid Content of the Associated Lignin
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DOI：
10.1002/bit.22981
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发表时间：
2011-03-01
影响因子：
3.8
通讯作者：
Saddler, Jack N.
中科院分区：
文献类型：
--
作者：
Nakagame, Seiji;Chandra, Richard P.;Saddler, Jack N.
为了评估木质素的物理和化学性质对预处理木质纤维素底物酶解的影响，从蒸汽和有机溶剂预处理的玉米秸秆、杨树和黑松中分离出蛋白酶处理木质素（PTL）和纤维素水解酶木质素（CEL）馏分，并对其进行了表征。纤维素酶对分离木质素的吸附符合Langmuir吸附等温线。很明显，当将木质素加入到典型的纯纤维素水解过程中（Avicel）时，通过红外光谱和核磁共振光谱测定的木质素的羧酸功能，而不是分离木质素的物理性质，对分离木质素的影响要大得多。木质素制备中羧酸含量的增加导致水解率的增加。这些结果表明，木质素中的羧酸部分缓解了纤维素酶与木质素的非生产性结合。为了证实这一可能的机制，以松柏醇（CA）和阿魏酸（FA）为原料合成了单脂醇的脱氢聚合物（DHP），并将这些模型化合物加入到典型的酶解Avicel中。与来自CA的DHP相比，来自FA的DHP富含羧酸基团，与来自CA的DHP相比，来自FA的DHP吸附了更少的纤维素酶，并且没有降低水解率，与来自CA的DHP相比，Avicel的水解率降低了8.4%。因此，增加木质素的羧酸含量似乎显著降低了纤维素酶的非生产性结合，从而增加了纤维素的酶解。Biotechnol。Bioeng。2011;108: 538 - 548。(C) 2010 Wiley期刊公司
To assess the effects that the physical and chemical properties of lignin might have on the enzymatic hydrolysis of pretreated lignocellulosic substrates, protease treated lignin (PTL) and cellulolytic enzyme lignin (CEL) fractions, isolated from steam and organosolv pretreated corn stover, poplar, and lodgepole pine, were prepared and characterized. The adsorption of cellulases to the isolated lignin preparations corresponded to a Langmuir adsorption isotherm. It was apparent that, rather than the physical properties of the isolated lignin, the carboxylic acid functionality of the isolated lignin, as determined by FTIR and NMR spectroscopy, had much more of an influence when lignin was added to typical hydrolysis of pure cellulose (Avicel). An increase in the carboxylic content of the lignin preparation resulted in an increased hydrolysis yield. These results suggested that the carboxylic acids within the lignin partially alleviate non-productive binding of cellulases to lignin. To try to confirm this possible mechanism, dehydrogenative polymers (DHP) of monolignols were synthesized from coniferyl alcohol (CA) and ferulic acid (FA), and these model compounds were added to a typical enzymatic hydrolysis of Avicel. The DHP from FA, which was enriched in carboxylic acid groups compared with the DHP from CA, adsorbed a lower mount of cellulases and did not decrease hydrolysis yields when compared to the DHP from CA, which decreased the hydrolysis of Avicel by 8.4%. Thus, increasing the carboxylic acid content of the lignin seemed to significantly decrease the non-productive binding of cellulases and consequently increased the enzymatic hydrolysis of the cellulose. Biotechnol. Bioeng. 2011; 108: 538-548. (C) 2010 Wiley Periodicals, Inc.