Structural Characterization of the Lignin from Jute (Corchorus capsularis) Fibers
2009 (English)In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 57, no 21, 10271-10281 p.Article in journal (Refereed) Published
The structural characteristics of the lignin from jute (Corchorus capsularis) fibers, which are used for high-quality paper pulp production, were studied. The lignin content (13.3% Klason lignin) was high compared to other nonwoody bast fibers used for pulp production. The lignin structure was characterized by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), 2D-NMR, and thioacidolysis. Upon Py-GC/MS, jute fibers released predominantly products from syringylpropanoid units with the S/G ratio being 2.1 and a H/G/S composition of 2:33:65. 2D-NMR of the milled wood lignin (MWL) isolated from jute fibers showed a predominance of beta-O-4' aryl ether linkages (72% of total side chains), followed by beta-beta' resinol-type linkages (16% of total side chains) and lower amounts of beta-5' phenylcoumaran (4%) and beta-1' spirodienone-type (4%) linkages and cinnamyl end groups (4%). The high predominance of the S-lignin units, together with the high proportion of beta-O-4' aryl ether linkages, which are easily cleaved during alkaline cooking, are advantageous for pulping. On the other hand, a small percentage (ca. 4%) of the lignin side chain was found to be acetylated at the gamma-carbon, predominantly over syringyl units. The analysis of desulphurated thioacidolysis dimers provided additional information on the relative abundances of the various carbon-carbon and diaryl ether bonds and the type of units (syringyl or guaiacyl) involved in each of the above linkage types. Interestingly, the major part of the beta-beta' dimers included two syringyl units, indicating that most of the beta-beta' substructures identified in the HSQC spectra were of the syringaresinol type (pinoresinol being absent), as already observed in the lignin of other angiosperms.
Place, publisher, year, edition, pages
2009. Vol. 57, no 21, 10271-10281 p.
Jute, Corchorus capsularis, nonwood fibers, pyrolysis-GC/MS, HSQC, thioacidolysis, milled wood lignin, syringyl, guaiacyl, syringaresinol, nmr-spectroscopy, hardwood lignins, chemical-characterization, lipid, fractions, wood lignin, dfrc method, delignification, thioacidolysis, spectrometry, softwood
IdentifiersURN: urn:nbn:se:kth:diva-18908DOI: 10.1021/jf900815xISI: 000271290800058ScopusID: 2-s2.0-70449086441OAI: oai:DiVA.org:kth-18908DiVA: diva2:336955
QC 201005252010-08-052010-08-052010-12-17Bibliographically approved