Pyrolysis Products Distribution of Enzymatic Hydrolysis Lignin with/without Steam Explosion Treatment by Py-GC/MS

Abstract

This paper investigated the pyrolytic behaviors of enzymatic hydrolysis lignin (EHL) and EHL treated with steam explosion (EHL-SE) by pyrolysis-gas chromatography/mass spectrometer (Py-GC/MS). It was shown that the main component of the pyrolysis products was phenolic compounds, including G-type, H-type, S-type, and C-type phenols. With different treatment methods, the proportion of units in phenolic products had changed significantly. Meanwhile, proximate, elemental, and FTIR analysis of both lignin substrates were also carried out for a further understanding of the lignin structure and composition with or without steam explosion treatment. FTIR result showed that, after steam explosion treatment, the fundamental structural framework of the lignin substrate was almost unchangeable, but the content of lignin constituent units, e.g., hydroxyl group and alkyl group, evidently changed. It was noticeable that 2-methoxy-4-vinylphenol with 11% relative content was the most predominant pyrolytic product for lignin after steam explosion treatment. Combined with the above analysis, the structural change and pyrolysis product distribution of EHL with or without steam explosion treatment could be better understood, providing more support for the multi-functional utilization of lignin.

Structural, physicochemical and functional properties of dietary fibers from tea residue modified by steam explosion

“…The FTIR spectra of DF from tea residue before and after SE are shown in Figure 4. The absorption peaks near 3,400 cm −1 , 2,920 cm −1 , 1,630 cm −1 , and 1,060 cm −1 represented stretching vibration generated by O-H, C-H, C=O, and C-O-C/O-H of DF, respectively, which conformed to the typical infrared absorption spectrum characteristics of polysaccharides (Ma and Mu, 2015;Dong et al, 2020). After SE treatment, the IDF generated a red shift from 3,400 cm −1 to 3,357 cm −1 (Figure 4A), indicating partial degradation of cellulose and hemicellulose components in the raw material (Zheng et al, 2021).…”

Effect of Steam Explosion on the Morphological, Textural and Chemical Composition Characteristics of Betel Nut

“…Under steam explosion at high temperature, high pressure and high humidity, studies have shown that hemicellulose, a heterogeneous multimer consisting of many different monosaccharides, is the most unstable and prone to thermal hydrolysis, producing xylose, arabinose, glucose, galactose, furfural or hydroxymethylfurfural, etc., and hydrolysis of acetyl groups generates organic acids, which also accelerates the decomposition of other substances (Jacquet et al, 2015;Sun et al, 2015). As phenolic polymers, lignin undergoes a series of cleavages, rearrangements and breakdowns that can produce phenolics or phenolic acids and benzene derivatives (Dong et al, 2020). Additionally, cellulose undergoes thermal degradation in which the glycosidic bonds are cleaved to form monosaccharides, and the breaking of the C-C bond in furanose forms small molecules, as similarly occurs in hemicellulose, thereby reducing the absolute cellulose content.…”

Effect of steam explosion on the morphological, textural, and compositional characteristics of betel nut

“…Hydrogen ions attack the ether bonds on the hemicellulose molecular chain to cause an electrophilic reaction, promoting the degradation of hemicellulose (Wang et al, 2020). Lignin undergoes a series of cleavages, rearrangements, and breakdowns that can produce phenolics or phenolic acids and benzene derivatives (Dong et al, 2020). The increased moisture of the samples also caused betel nut fiber softening, reducing the mechanical bond strength (Chang et al, 2012).…”