The acetyl bromide method is faster, simpler and presents best recovery of lignin in different herbaceous tissues than Klason and thioglycolic acid methods

PLoS One. 2014 Oct 16;9(10):e110000. doi: 10.1371/journal.pone.0110000. eCollection 2014.

Abstract

We compared the amount of lignin as determined by the three most traditional methods for lignin measurement in three tissues (sugarcane bagasse, soybean roots and soybean seed coat) contrasting for lignin amount and composition. Although all methods presented high reproducibility, major inconsistencies among them were found. The amount of lignin determined by thioglycolic acid method was severely lower than that provided by the other methods (up to 95%) in all tissues analyzed. Klason method was quite similar to acetyl bromide in tissues containing higher amounts of lignin, but presented lower recovery of lignin in the less lignified tissue. To investigate the causes of the inconsistencies observed, we determined the monomer composition of all plant materials, but found no correlation. We found that the low recovery of lignin presented by the thioglycolic acid method were due losses of lignin in the residues disposed throughout the procedures. The production of furfurals by acetyl bromide method does not explain the differences observed. The acetyl bromide method is the simplest and fastest among the methods evaluated presenting similar or best recovery of lignin in all the tissues assessed.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / chemistry*
  • Chemical Fractionation / methods*
  • Furaldehyde / analogs & derivatives
  • Furaldehyde / analysis
  • Glycine max / chemistry
  • Glycine max / cytology*
  • Lignin / analysis*
  • Lignin / isolation & purification*
  • Mechanical Phenomena
  • Saccharum / chemistry
  • Saccharum / cytology*
  • Thioglycolates / chemistry*
  • Time Factors

Substances

  • Acetates
  • Thioglycolates
  • 5-hydroxymethylfurfural
  • 2-mercaptoacetate
  • Lignin
  • Furaldehyde
  • acetyl bromide

Grants and funding

This work was supported by CNPq (http://www.cnpq.br/) grant 310303/2011-7). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.