Studies on lignin biosynthesis and structure

dc.contributor.authorEberhardt, Thomas Leonarden
dc.contributor.committeechairLewis, Norman G.en
dc.contributor.committeememberIfju, Gezaen
dc.contributor.committeememberGlasser, Wolfgang G.en
dc.contributor.departmentForest Productsen
dc.date.accessioned2014-03-14T21:33:36Zen
dc.date.adate2010-04-12en
dc.date.available2014-03-14T21:33:36Zen
dc.date.issued1988-02-15en
dc.date.rdate2010-04-12en
dc.date.sdate2010-04-12en
dc.description.abstractBeech (<u>Fagus grand1folia</u> Ehrh.> bark contains appreciable quantities of Z- (cis) con1feryl and Z-s1napyl alcohols and not the corresponding E- (trans) alcohols. Previous rad1otracer experiments suggested that the Z-coniferyl alcohol in beech bark is formed by isomerization of E-coniferyl alcohol which proceeds either directly or through the corresponding aldehydes. In the work conducted in this thesis, is has been found that crude cinnamy1 alcohol dehydrogenase isolated from beech bark shows a strong substrate preference for E-coniferyl alcohol (as opposed to Z-coniferyl alcohol) thereby suggesting that the E to Z isomerization described occurs directly at the alcohol level. Administration of (2-¹⁴C) ferul1c acid to feland wheat (<u>Triticum aest1yum</u> L.) over extended durations (21 days) and subsequent isolation of the lignin from the root tissue as its acetal derivative demonstrated the incorporation of the labelled feru1ic acid into the lignin component of the tissue. Through sim1lar administrations of (1-¹³C, 2-¹³C and 3-¹³C) ferul1c acid and subsequent analysis of the root tissues by solid state ¹³C nuclear magnetic resonance (NMR) spectroscopy, it was possible to determine the bonding patterns of lignin in situ. The lignin component of each ¹³C feru1ic acid enriched root tissue was then isolated as its acetal derivative and analyzed by solution state ¹³C NMR. Through comparison it was shown that the enhanced resonances observed in the solution state ¹³C NMR spectra of the ¹³C ferulic acid enriched acetal lignins corresponded to the enhanced resonances in the respective spectra of the intact root tissues. This indicated that minimal changes to the lignin bonding patterns occurred during the isolation procedure. The dominant presence of ¹³C NMR resonances corresponding to hydroxycinnamic acid functionalities in the solid and solution state NMR spectra demonstrates the important role of hydroxyc1nnamic acids in wheat root lignin. However, no evidence of the formation of dimers such as 4,4'-dihydroxytruxillic acid was noted. Thus, such structures do not represent an important bonding pattern in wheat root lignin.en
dc.description.degreeMaster of Scienceen
dc.format.extentx, 111 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-04122010-083702en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-04122010-083702/en
dc.identifier.urihttp://hdl.handle.net/10919/42045en
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1988.E347.pdfen
dc.relation.isformatofOCLC# 18115963en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V855 1988.E347en
dc.subject.lcshLignin -- Biodegradationen
dc.subject.lcshLigninen
dc.titleStudies on lignin biosynthesis and structureen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineForest Productsen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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