Joe Linn, undergraduate student in Chemical Engineering, applying C13-labeled
thermochemolysis to track the alteration of biofuel feedstocks (e.g.,
wood and stover) by fungi.
Progressive brown rot decay to remove polysaccharides.
Brown rot wood-degrading fungi accomplish naturally what bioconversion technologies
currently do not: complete removal (>99%) of plant polysaccharides from
lignocellulosic tissues without removing or damaging lignin. The lignin
modifications (demethylation, depolymerization, hydroxylation) seen in residues
from brown rot fungi may be an important link to understanding fungal mechanisms
of sugar release (saccharification). While the predominant theory has been
that modifications increase pore size and thus allow enzymes to penetrate
the plant cell wall, most brown rot fungi cannot degrade crystalline cellulosics
if lignin is absent. This observation remains unresolved and characterizing
this dynamic has significant implications for commercial biorefining.
Thanks to a Department of Energy grant, "Brown-rot Fungal Mechanisms as
a Model for Biomass Saccharification"Co-PI with Robert Blanchette and Jonathan
Schilling of the University of Minnesota the lab has been able to pursue fruther research in this area.
We hypothesize that lignin modifications precede enzyme-mediated hydrolysis
and that modified lignin actively facilitates saccharification during brown
rot. Successfully utilizing an approach similar to that of brown rot fungi
offers an alternative to engineering plants with altered lignin content
or to delignifying feedstocks prior to processing. We have strong commercial
participation in this project. With the goal being to characterize then
utilize the brown rot approach to enhance C5 and C6 sugar release from biomass,
our specific aims are to:
- determine the discrete timing of lignin modifications;
- correlate these alterations with biocatalyst efficiency and ingress into plant cell walls;
- reproduce modifications prior to saccharification for efficient bioprocessing.
Our research in this area includes:
Schilling, J., J., Jun Ai; Blanchette;, R.A., Duncan, S..A., Filley, T.R., Tschirner, U.W. (2012) Lignocellulose modifications by brown rot fungi and their effects, as pretreatments, on cellulolysis. Bioresource Technology 116, 147-154.
Arantes,V., Milagres, AEM., Filley, T.R., Goodell, B (2010). Lignocellulosic polysaccharides and lignin degradation via nonenzymatic Fenton-based reactions mediated by Fe3+-reductants purified from cultures of wood decay fungi. Journal of Industrial Microbiology & Biotechnology DOI: 10.1007/s10295-010-0798-2.
Arantes, V., Y. Qian, S. S. Kelley, A. M. F. Milagres, T. R. Filley, J. Jellison, B. Goodell (2009) Biomimetic oxidative treatment of spruce wood studied by pyrolysis–molecular beam mass spectrometry coupled with multivariate analysis and 13C-labeled tetramethylammonium hydroxide thermochemolysis: implications for fungal degradation of wood, J. Biol. Inorg. Chem. doi: 10.1007/s00775-009-0569-6.
Filley, T.R (2003) Assessment of fungal wood decay by lignin analysis using tetramethylammonium hydroxide (TMAH) and C-13-labeled TMAH thermochemolysis In: Wood Deterioration and Preservation-Advances in our Changing Worl
Filley, T.R., Cody, G.D., Goodell, B. et al. (2002) Lignin demethylation and polysaccharide
decomposition in spruce sapwood degraded by brown rot fungi. Organic Geochemistry, 33, 111-