Structural Characterization of Corn Stover Lignin after Hydrogen Peroxide Presoaking Prior to Ammonia Fiber Expansion Pretreatment

Abstract

The hydrogen peroxide presoaking prior to ammonia fiber expansion (H-AFEX) pretreatment is an effective and promising method for agricultural residues to decrease biomass recalcitrance and enhance enzyme accessibility. To illuminate the structural changes of lignin after the H-AFEX process, ball-milled wood lignins were isolated from raw material and H-AFEX-treated corn stover. The features and structures of the obtained lignins were characterized by elemental analysis, gel permeation chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The results demonstrated that the H-AFEX-treated lignins had higher oxygen and nitrogen contents while lower carbon and hydrogen contents when compared to those of untreated lignin. A remarkable decrease in molecular weight of H-AFEX-treated lignin was observed. Ammonolysis, hydrolysis, and oxidation reactions were major chemical modifications to lignin, and the cleavages of ferulate and p-coumarate ester bonds, alkyl ether bonds, and aryl ether bonds were observed during the H-AFEX process. G unit lignin was more easily degraded through demethoxylation, while the interunit linkages of resinol and phenylcoumaran were relatively stable. The study on lignin structural changes during the H-AFEX process could reveal the pretreatment mechanism and develop of a new pretreatment method, with a perspective of reducing biomass recalcitrance and improving the bioconversion of biomass to biofuels or biomaterials.

Cerium oxide nanoparticle functionalized lignin as a nano-biosorbent for efficient phosphate removal

“…By one estimate, >7 Â 10 8 tons of lignin is obtained as a waste from papermaking and biorenery industries every year. [7][8][9][10][11] However, only <10% lignin is developed to be a value-added chemical and material, [12][13][14][15][16][17][18][19] and the remaining (>90%) is burned as a low-value fuel. Recently, there has been considerable interest for converting lignin into a highperformance biosorbent for removing pollutants from wastewater because of its advantages of being abundance, low cost, sustainability, environmental-friendliness, and rich reactivity.…”

Urinary metabolomics research for Huangqi Jianzhong Tang against chronic atrophic gastritis rats based on 1H NMR and UPLC-Q/TOF MS

“…from herbs might introduce unexpected insights into its chemical constituents and material basis research in future. [ ]…”

Fast Isolation of Flavonoids from the Endemic Species Nolana ramosissima I.M. Johnst and Its Endothelium-Independent Relaxation Effect in Rat Aorta

“…Furthermore, from the extrusion partition of the HSCCC run, only hydroxypalmitic acid (Peak 61) and inseparable mixtures of fatty acids were isolated. Other potential approaches to pre-treat and extract the active compounds are nowadays employed, including experimental approaches for the identification after elimination of the effect of matrix on quantitative analyses by HPLC−MS, such as CO 2 extraction, pretreatment with ammonia and hydrogen peroxide, pressurized solvents; however, infusion is the typical edible form, and methanol extraction at ambient temperature proved to be good solvent to extract all the flavonoids and phenolics in our Nolana species for purification purposes [31][32][33]. -6 ).…”