The Nature of Hololignin

Journal Article · Tue Nov 07 00:00:00 EST 2017 · ACS Sustainable Chemistry & Engineering

DOI:https://doi.org/10.1021/acssuschemeng.7b03285· OSTI ID:1427613

Meng, Xianzhi ^[1]; Pu, Yunqiao  ^[2]; Sannigrahi, Poulomi ^[3]; Li, Mi  ^[2]; Cao, Shilin ^[4]; Ragauskas, Arthur J.  ^[5]

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1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemical and Biomolecular Engineering
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division
3. Georgia Inst. of Technology, Atlanta, GA (United States). School of Chemistry and Biochemistry
4. Fujian Agriculture and Forestry Univ., Fuzhou (China). College of Material Engineering
5. Univ. of Tennessee, Knoxville, TN (United States). Center of Renewable Carbon, Inst. of Agriculture and Dept. of Chemical and Biomolecular Engineering and Dept. of Forestry, Wildlife and Fisheries; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division

Acid chlorite delignification is frequently used to obtain a mixture of cellulose and hemicellulose known as holocellulose from biomass. While a majority of lignin is removed after holocellulose pulping, there appears to be a minor fraction of lignin that is more resistant to acid chlorite treatment and remains in the holocellulose even after repeated delignification treatment. This type of lignin, defined as hololignin, has not been characterized, is likely to contribute to biomass recalcitrance and is clearly of fundamental interest to understand its structural characteristics. In this study, hololignin isolated from poplar holocellulose was characterized with a wide array of techniques including GPC, quantitative ¹³C, DEPT-135, HSQC, and ³¹P NMR. The results were then compared to those from milled wood lignin (MWL), the representative native lignin isolated from poplar. NMR analysis demonstrated a depletion of cinnamyl aldehyde, acetyl group, and decrease of p-hydroxybenzoate structural units in hololignin. An enrichment of condensed structures in hololignin was observed. Hololignin also had a significantly lower molecular weight than MWL. Finally, hololignin is relatively enriched in guaiacyl units and has a lower S/G ratio, lower β-O-4 ether linkages, fewer aliphatic and phenolic hydroxyl groups, and more carboxylic acid groups than MWL.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1427613
• Journal Information: ACS Sustainable Chemistry & Engineering, Vol. 6, Issue 1; ISSN 2168-0485
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Acid chlorite
Delignification
Holocellulose pulping
Hololignin
Milled wood lignin