BioEnergy Science Center, School of Chemistry and Biochemistry, Institute of Paper Science and Technology, Georgia Institute of Technology, 500 10th Street, Atlanta, GA 30332, USA.
Bioresour Technol. 2012 Aug;117:7-12. doi: 10.1016/j.biortech.2012.04.037. Epub 2012 Apr 21.
Pseudo-lignin, which can be broadly defined as aromatic material that yields a positive Klason lignin value and is not derived from native lignin, has been recently reported to form during the dilute acid pretreatment of poplar holocellulose. To investigate the chemistry of pseudo-lignin formation, GPC, FT-IR and 13C NMR were utilized to characterize pseudo-lignin extracted from dilute-acid pretreated α-cellulose and holocellulose. The results showed that pseudo-lignin consisting of carbonyl, carboxylic, aromatic and aliphatic structures was produced from dilute acid pretreated cellulose and hemicellulose. Pseudo-lignin extracted from holocellulose pretreated at different conditions had similar molecular weights (Mn∼1000 g/mol; Mw∼5000 g/mol) and structural features (carbonyl, carboxylic, aromatic and methoxy structures). These characterizations have provided the pseudo-lignin formation mechanisms during pretreatment. The presence and structure of pseudo-lignin is important since pseudo-lignin decreases the enzymatic conversion.
拟木素是一种广泛定义的芳香族物质，它可以产生阳性的克氏木质素值，并且不是来自天然木质素。最近有报道称，它在杨树木质素全纤维素的稀酸预处理过程中形成。为了研究拟木素形成的化学性质，利用 GPC、FT-IR 和 13C NMR 对从稀酸预处理的α-纤维素和全纤维素中提取的拟木素进行了表征。结果表明，拟木素由羰基、羧酸、芳基和脂肪族结构组成，是由稀酸预处理的纤维素和半纤维素产生的。用不同条件预处理的全纤维素提取的拟木素具有相似的分子量（Mn∼1000 g/mol；Mw∼5000 g/mol）和结构特征（羰基、羧酸、芳基和甲氧基结构）。这些特征为预处理过程中拟木素的形成机制提供了依据。拟木素的存在和结构很重要，因为它会降低酶的转化。
