文獻名：Acid hydrotropic fractionation of switchgrass at atmospheric pressure using maleic acid in comparison with p-TsOH: Advantages of lignin esterification

作者： Chen Su^ab, Kolby Hirth^b, Zhulan Liu^a, Yunfeng Cao^a, J.Y. Zhu^b

^aJiangsu Co-innovation Center for Efficient Processing and Utilization of Forest Resources, Jiangsu Provincial Key Lab Pulp & Paper Science and Technology, Nanjing Forestry University, Nanjing, 210037, China

^bUSDA Forest Service, Forest Products Laboratory, Madison, WI, USA

摘要：Switchgrass was fractionated using maleic acid (MA) as an acid hydrotrope in comparison with p-toluenesulfonic acid (p-TsOH) at atmospheric pressure. MA achieved more rapid and greater maximal dissolution of lignin and hemicelluloses (88 % and 63 %, respectively) than did p-TsOH (73 % and 55 %, respectively). MA esterified (carboxylated) the dissolved acid hydrotropic lignin (AHL) as evidenced by 2D ¹H-¹³C HSQC NMR analysis, which improved AHL antioxidant ability compared with AHL from p-TsOH that is not carboxylated. MA also carboxylated the lignin and cellulose in the fractionated cellulosic water-insoluble solids (WIS), which significantly improved WIS enzymatic digestiblity for sugar production than did p-TsOH with the same level of delignification. It also improved the lignin lubrication effect to facilitate mechanical fibrillation of WIS into lignocellulosic nanofibrils. MA is an FDA-approved indirect food additive (21CFR175-177) with lower acidity and solubility than p-TsOH, which substantially benefits recycling and decreasing environmental impacts to achieve sustainability.

關鍵詞：Maleic acid fractionation; Lignin esterification; Lignin-containing cellulose nanofibrils (LCNFs); Antioxidant activity

Structural characteristics