OSU researchers study rumen fungus for biofuel production

By Oklahoma State University | June 14, 2013

A group of researchers from Oklahoma State University have published the first analysis of a genome they say has great potential for the cost-effective production of biofuel. The analysis will appear in the August issue of Applied and Environmental Microbiology.

The team, led by Mostafa Elshahed, associate professor of microbiology and molecular genetics, and solely comprised of researchers from the state of Oklahoma, has described multiple unique features within the genome of rumen fungus, organisms that reside in the gut of ruminant animals.

The team found the fungus to be remarkably efficient at digesting plant biomass – something Elshahed says makes it an extremely interesting, and yet-rarely utilized, candidate for biofuel production.

“Unlike the absolute majority of fungi that are free-living and breathe atmospheric oxygen, rumen fungi have a restricted habitat in the rumen and alimentary tract of herbivores,” he said.  “They grow in the absence of oxygen, have adapted their genome to living in the presence of a large and diverse number of bacteria, and have even acquired useful genes from these bacteria, including multiple genes that aid in digestion of plant biomass.”

The team’s genomic and experimental analyses indicate the fungus efficiently degrades a wide range of non-crop plant materials, such as switchgrass, corn stover, sorghum and energy cane.  The extent of plant biomass degradation has rarely been observed in other microorganisms.

“The concurrent capability of plant biomass degradation, known as saccharification, and product formation from sugars, known as fermentation, renders anaerobic fungi very promising agents for consolidating various processes in a biofuel production scheme, an approachthat significantly lowers the cost of biofuel production,” Elshahed said.

The next phase of the team’s work will be to improve the ratio of ethanol to acids produced by the degradation of plant biomass from this fungus. The fungus currently produces more acids than ethanol as a final product.

“There are many ways to tackle this problem, which I believe is very solvable,” Elshahed said.  “We are experimenting with various approaches to shift the process to alcohol production from acids, and already, some of the schemes are working very well.  With these enhanced ethanol production levels in mind, we are embarking on an evaluation of the economies and practical feasibility of the process to demonstrate that this obscure, small fungus could play a large role in future commercial energy production schemes in the U.S.”