Journal of Analytical and Applied Pyrolysis
64 (2002) 421–431
www.elsevier.com/locate/jaap
Lignin attack during eucalypt wood decay by
selected basidiomycetes: a Py-GC/MS study
J.C. del Rı ´o
a,
*, M. Speranza
b,c
, A. Gutie ´rrez
a
,
M.J. Martı ´nez
c
, A.T. Martı ´nez
c
a
Instituto de Recursos Naturales y Agrobiologı ´a de Seilla, CSIC, PO Box 1052, E-41080,
Seille, Spain
b
Facultad de Ciencias, Uniersidad de la Repu ´blica, C.P. 11400 Monteideo, Uruguay
c
Centro de Inestigaciones Biolo ´gicas, CSIC, Vela ´zquez 144, E-28006 Madrid, Spain
Received 1 August 2001; accepted 17 December 2001
Abstract
The degradation patterns of Eucalyptus globulus wood by several basidiomycetes isolated
from naturally-decayed wood in eucalypt plantations in Uruguay were studied by analytical
pyrolysis coupled to gas chromatography/mass spectrometry. Relative peak areas were
calculated for pyrolysis products derived from guaiacylpropanoid (G) and syringylpropanoid
(S) lignin units, as well as for products arising from carbohydrates. The fungal strains used
were found to be efficient lignin degraders on eucalypt wood as revealed by lignin/carbohy-
drate ratio from pyrolysis products. Simultaneously, a decrease of lignin S/G ratio was
observed during wood delignification. This is due to the preferential biodegradation of
S-units, which are predominantly ether-linked, compared with G-units that are more
recalcitrant towards fungal attack because of the presence of biphenyl-type structures. Both
the lowest lignin/carbohydrate and S/G ratios were found in the wood treated with a
Phanerochaete crassa strain. Subtle modifications of residual lignin in wood were evidenced
by changes in relative abundance of pyrolysis products after fungal decay. © 2002 Elsevier
Science B.V. All rights reserved.
Keywords: Eucalyptus globulus ; Wood; Lignin; Cellulose; White-rot basidiomycetes; Phanerochaete
crassa
* Corresponding author. Tel.: +34-95-462-4711; fax: +34-95-462-4002
E-mail address: delrio@irnase.csic.es (J.C. del Rı ´o).
0165-2370/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved.
PII:S0165-2370(02)00043-8