Identification of developmental stage and anatomical fraction contributions to cell wall recalcitrance in switchgrass.
Identification of developmental stage and anatomical fraction contributions to cell wall recalcitrance in switchgrass.
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DOI：
10.1186/s13068-017-0870-5
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发表时间：
2017
影响因子：
6.3
通讯作者：
Hodge DB
中科院分区：
文献类型：
--
作者：
Crowe JD;Feringa N;Pattathil S;Merritt B;Foster C;Dines D;Ong RG;Hodge DB
草本生物质的异质性对加工纤维素生物燃料的原料提出了重要的挑战。植物生长过程中细胞壁组成和组织的改变是单一物种或栽培品种异质性的主要贡献。为了解决这一挑战，本研究的重点是表征植物细胞壁的组成和特性之间的关系，以及通过不同节间评估不同组织成熟度柳枝稷解剖部分（茎节间、叶鞘和叶片）的NaOH预处理和酶解对细胞壁解构的反应。观察到细胞壁组成和对解构的反应的实质性差异是解剖分数和组织成熟度的函数。值得注意的是，木质素含量随着组织成熟度的增加而增加，同时阿魏酸含量在所有三个解剖部位都有所下降。茎节间木质素含量最高，水解率最低，且与木质素含量呈负相关。共聚焦显微镜显示，NaOH预处理对细胞壁芳香烃（木质素和羟基肉桂酸）的去除在不同细胞类型中是不均匀的。非纤维素多糖与细胞壁对低木质素组分的解构反应的差异有关。其中叶鞘和叶片中葡萄糖醛酸和果胶多糖的含量较高。糖谱分析表明，木聚糖和果胶多糖的提取能力随茎节间成熟度的变化而变化，相对于不成熟的节间，更成熟的节间需要更严格的化学提取来去除相当的多糖丰度。虽然酶解对无提取物的生物质进行，但可提取糖（即淀粉和蔗糖）占总干重的很大一部分，特别是在茎节间，并且可能在加工过程中提供回收的机会。单个植物内的细胞壁结构差异可以在原料特性中发挥重要作用，并且在生物精炼过程中有可能被用于改善生物质的可加工性。这项工作的结果表明，细胞壁木质素含量虽然通常与酶解产量呈负相关，但并不是柳枝稷中不同解剖部分细胞壁顽固性的唯一因素。本文的在线版本（doi:10.1186/s13068-017-0870-5）包含补充材料，可供授权用户使用。
Heterogeneity within herbaceous biomass can present important challenges for processing feedstocks to cellulosic biofuels. Alterations to cell wall composition and organization during plant growth represent major contributions to heterogeneity within a single species or cultivar. To address this challenge, the focus of this study was to characterize the relationship between composition and properties of the plant cell wall and cell wall response to deconstruction by NaOH pretreatment and enzymatic hydrolysis for anatomical fractions (stem internodes, leaf sheaths, and leaf blades) within switchgrass at various tissue maturities as assessed by differing internode. Substantial differences in both cell wall composition and response to deconstruction were observed as a function of anatomical fraction and tissue maturity. Notably, lignin content increased with tissue maturity concurrently with decreasing ferulate content across all three anatomical fractions. Stem internodes exhibited the highest lignin content as well as the lowest hydrolysis yields, which were inversely correlated to lignin content. Confocal microscopy was used to demonstrate that removal of cell wall aromatics (i.e., lignins and hydroxycinnamates) by NaOH pretreatment was non-uniform across diverse cell types. Non-cellulosic polysaccharides were linked to differences in cell wall response to deconstruction in lower lignin fractions. Specifically, leaf sheath and leaf blade were found to have higher contents of substituted glucuronoarabinoxylans and pectic polysaccharides. Glycome profiling demonstrated that xylan and pectic polysaccharide extractability varied with stem internode maturity, with more mature internodes requiring harsher chemical extractions to remove comparable glycan abundances relative to less mature internodes. While enzymatic hydrolysis was performed on extractives-free biomass, extractible sugars (i.e., starch and sucrose) comprised a significant portion of total dry weight particularly in stem internodes, and may provide an opportunity for recovery during processing. Cell wall structural differences within a single plant can play a significant role in feedstock properties and have the potential to be exploited for improving biomass processability during a biorefining process. The results from this work demonstrate that cell wall lignin content, while generally exhibiting a negative correlation with enzymatic hydrolysis yields, is not the sole contributor to cell wall recalcitrance across diverse anatomical fractions within switchgrass. The online version of this article (doi:10.1186/s13068-017-0870-5) contains supplementary material, which is available to authorized users.
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影响因子：
1.9
作者：
Donaldson, Lloyd
通讯作者：
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影响因子：
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作者：
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作者：
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DOI：
10.1073/pnas.1113971108
发表时间：
2011-10-18
影响因子：
11.1
作者：
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