A Fungal End to Coal in the Carboniferous Period?

Insights into the origin of ligninases can help develop processes to convert biomass into bioenergy.

Image courtesy of Lawrence Berkeley National Laboratory
Amanita muscaria of the class Agaricomycetes.

The Science

An international team of scientists from Clark University and the Department’s Joint Genome Institute has proposed that a species of fungus, first appearing at about the end of the Carboniferous, could more efficiently break down dead plant matter, possibly leading to the decline in coal formation.

The Impact

This research, provides insights into the origin of ligninases that can be used to develop processes that use these enzymes to convert plant and tree biomass into bioenergy products.


Much of the world’s coal was generated 300–360 million years ago during the Carboniferous period. Wood (a major pool of organic carbon that is highly resistant to decay largely due to its lignin content) was deposited, transformed to peat, and eventually transformed to coal. But coal formation may also have declined from an unlikely source - fungi. These fungi had enzymes (ligninases) capable of degrading lignin, a category of enzyme important for the Department of Energy’s bioenergy mission, since lignin in plant biomass hinders biomass conversion to biofuels. By comparing the genomic sequences of 31 fungi, including 12 sequenced for this study, the researchers showed that genes able to degrade lignin first appeared at the end of this period. Instead of becoming coal, the plant biomass decayed and the carbon was released into the atmosphere as carbon dioxide.


Dr. Igor Grigoriev
Lawrence Berkeley National Laboratory


Basic Research: DOE Office of Science, Office of Biological and Environmental Research


D. Floudas, et.al. (2012) “The Paleozoic Origin of Enzymatic Lignin Decomposition Reconstructed from 31 Fungal Genomes”, Science v.336: 1715–1719

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