From fungus to fuel
An international team of researchers led by some U.S. Department of Energy's research labs has decoded the genetic sequence of a fungus named Tricoderma reesei. The team has found how this organism breaks down plant fibers into simple sugars and how to use this fungus to produce fuel. 'The finding could unlock possibilities for industrial processes that can more efficiently and cost effectively convert corn, switch grass and even cellulose-based municipal waste into ethanol.' But read more...
You can see above a photo showing "a microscope image of the fungus Tricoderma reesei growth filaments. In the image, proteins in fungal cells are stained red, while chitin, a component of the cell walls, is stained blue." (Credit: Mari Valkonen, VTT Technical Research Center, Finland) Here are two links to a larger version of this photo and to the Wikipedia page about Trichoderma reesei.
Here are some of the interesting discoveries of the research team. "The organism uses enzymes it creates to break down human-indigestible fibers of plants into the simplest form of sugar, known as a monosaccharide. The fungus then digests the sugars as food. Researchers decoded the genetic sequence of T. reesei in an attempt to discover why the deep green fungus was so darned good at digesting plant cells. The sequence results were somewhat surprising. Contrary to what one might predict about the gene content of a fungus that can eat holes in tents, T. reesei had fewer genes dedicated to the production of cellulose-eating enzymes than its counterparts."
So how this fungus could be used to produce fuel? "'We were aware of T. reesei's reputation as producer of massive quantities of degrading enzymes, however we were surprised by how few enzyme types it produces, which suggested to us that its protein secretion system is exceptionally efficient,' said Los Alamos bioscientist Diego Martinez (also at the University of New Mexico), the study's lead author. [...] On an industrial scale, T. reesei could be employed to secrete enzymes that can be purified and added into an aqueous mixture of cellulose pulp and other materials to produce sugar. The sugar can then be fermented by yeast to produce ethanol.
This research work is available online from Nature Biotechnology as an advance online publication. The title of the paper is "Genome sequencing and analysis of the biomass-degrading fungus Trichoderma reesei (syn. Hypocrea jecorina)" (May 4, 2008). Here is a link to the abstract. "Trichoderma reesei is the main industrial source of cellulases and hemicellulases used to depolymerize biomass to simple sugars that are converted to chemical intermediates and biofuels, such as ethanol. [...] Our analysis, coupled with the genome sequence data, provides a roadmap for constructing enhanced T. reesei strains for industrial applications such as biofuel production."
It is interesting to note that this paper has been co-signed by 45 researchers from six countries, Austria, Chile, Finland, France, Spain and the U.S. If one of the researchers reads this post, please drop me a note to tell me how you collectively wrote this article. Did you use meetings, phone calls, e-mail or instant messaging exchanges? Or did you use a common blog or a Wiki? Thank you for your help.
Sources: Los Alamos National Laboratory news release, May 4, 2008; and various websites
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