Structural characterization of hemicellulose released from corn cob in continuous flow type hydrothermal reactor

Area of Science:

• Biomass valorization and carbohydrate chemistry.
• Focus on lignocellulosic biomass processing and hemicellulose extraction.

Background:

• Hydrothermal reactions are effective for hemicellulose extraction from lignocellulosic biomass.
• Corn cob is a readily available source of hemicellulose.

Purpose of the Study:

• To investigate the molecular structure of xylooligosaccharides extracted from corn cob using hydrothermal methods.
• To analyze the composition and modifications of corn cob xylan (CX) and its derivatives.

Main Methods:

• Hydrothermal reaction in a continuous flow reactor.
• Fractionation using ethanol precipitation.
• Structural elucidation using 1H-NMR spectroscopy and MALDI-TOF MS.
• Enzymatic hydrolysis with specific enzymes (acetylxylan esterase, GH3 β-xylosidase, GH10 and GH11 xylanases).

Main Results:

• The extracted hemicellulose (CX) is a mixture of acetylarabinoglucuronoxylan fragments with a wide degree of polymerization.
• CX contains unsubstituted regions and regions with acetylated, 4-O-methyl-d-glucuronic acid and arabinofuranose substituted xylopyranosyl residues.
• Acetylation and ferulic acid modifications contribute to high yield and solubility of CX.
• Enzymatic treatments yield diverse xylooligosaccharides with potential biomedical applications.

Conclusions:

• Hydrothermal extraction yields soluble corn cob xylan (CX) with significant acetylation and ferulic acid modifications.
• The structural features of CX, including acetylation and ferulic acid substitution, are crucial for its high yield and solubility.
• Enzymatic modification of CX can produce xylooligosaccharides with varied structures and potential biomedical relevance.