Effect of autohydrolysis and aromatic scavengers on delignification patterns and enzymatic hydrolysability were evaluated using miscanthus (MxG), empty palm fruit bunch (EFB) and typha grass residue as feedstocks. Autohydrolysis was carried out without naphthol and in the presence of naphthol followed by delignification by ethanol organosolv process. Despite their close chemical composition, the three feedstocks demonstrated quite different patterns of delignification under the same condition of pretreatment. Nuclear magnetic resonance (NMR) spectroscopic characterization of ethanol organosolv lignins (EOLs) extracted from the three feedstocks revealed information concerning syringyl, guaiacyl and hydroxyphenyl content (S/G/H ratios) which underpinned the differences among the feedstock behavior. The (S+H)/G ratios for MxG, EFB and typha were determined as   ?1.27,  ?2.33  and  ?2.70 respectively. The major cause of difference in behaviour of feedstock during the pretreatment process was attributed to the variation in lignin composition. A good relationship was observed between S/G ratio and the scavenging effect of 2-naphthol. Cellulolytic enzyme lignin (CEL) extracted from typha grass was also subjected to 13C NMR characterization in order to obtain a more complete picture of typha lignin.  Comparison of NMR spectra of CEL and EOL from TC was performed for determining the processing effect in lignin structure.

Delignification and recalcitrance: Influence of the lignin structure

247th National Meeting (2014)

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