Sanyal Udishnu, Wang Junxia, Wang Peipei, Ma Ruoshui, Velmurugan Santheeb Balaji, Lin Kuan-Ting, Zhang Xiao
Bioproducts, Sciences and Engineering Laboratory, Voiland School of Chemical Engineering and Bioengineering, Washington State University, Richland, WA, 99354, USA.
ChemSusChem. 2025 Jul 17;18(14):e202500026. doi: 10.1002/cssc.202500026. Epub 2025 May 22.
Developing a selective lignin depolymerization process remains a daunting challenge due to lignin's inherent structural heterogeneity and chemical complexity. This study used a novel deep eutectic solvent (DES) extraction to produce oligomeric lignin with controlled structural characteristics (narrow size distribution, lower molecular weight) and further subjected it to oxidative depolymerization using peracetic acid as an oxidant. Oxidation of lignin resulting from lactic acid/pyrazole and choline chloride/lactic acid extraction produces phenolic acids (Ph-COOH) and dicarboxylic acid (DCA) as significant products. Our results show that the judicial choice of DES during extraction plays a critical role in determining the lignin chemical structure, which follows different oxidation pathways and results in different product selectivities. The generalization of this concept has been established with two different parent lignins, e.g., Douglas fir (D.fir) and wheat straw (WS). The overall process showed that the novel DES extraction not only provides a sustainable pathway for high-purity lignin generation but also could be used as a tool to produce high-value products selectively upon its oxidation, thus improving the overall lignin biorefinery process.
由于木质素固有的结构异质性和化学复杂性，开发一种选择性木质素解聚工艺仍然是一项艰巨的挑战。本研究采用一种新型的低共熔溶剂（DES）萃取法来制备具有可控结构特征（窄尺寸分布、较低分子量）的低聚木质素，并进一步以过氧乙酸作为氧化剂对其进行氧化解聚。由乳酸/吡唑和氯化胆碱/乳酸萃取得到的木质素氧化产生酚酸（Ph-COOH）和二元羧酸（DCA）作为主要产物。我们的结果表明，萃取过程中DES的合理选择在决定木质素化学结构方面起着关键作用，这会遵循不同的氧化途径并导致不同的产物选择性。这一概念已通过两种不同的原始木质素（如道格拉斯冷杉（D.fir）和麦秸（WS））得到了推广。整个过程表明，新型的DES萃取不仅为生成高纯度木质素提供了一条可持续的途径，而且还可作为一种工具，在其氧化时选择性地生产高价值产品，从而改善整个木质素生物精炼过程。
