U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights


Biofuel Tech Straight from the Farm
Published: February 18, 2016
Posted: April 27, 2016

Microbes found in the digestive tract of large herbivores offer attractive enzyme platforms for lignocellulosic processing. [Image courtesy of iStock]

Herbivore digestion of lignocellulosic biomass involves a large variety of enzymes.

The Science
Herbivores eat many types of lignocellulosic plants, and fungi digest this material in the animals’ guts. A new study has characterized several fungi involved in this digestion process, identifying a large number of enzymes that work synergistically to degrade the raw biomass.

The Impact
Industry is exploring strategies to more effectively turn biomass like wood and grasses into fuel or chemicals. Because the matrix of complex molecules found in plant cell walls—lignin, cellulose, and hemicellulose—is difficult to break down using biological methods, costly pretreatments with heat or chemicals are necessary. The discovery of new, highly effective biomass-degrading enzymes in anaerobic fungi could accelerate the development of a process to convert lignocellulose feedstocks into fermentable sugars without pretreatment, potentially leading to more efficient conversion of raw biomass to biofuels and biobased products.

Summary
Scientists have long known that anaerobic fungi living in the guts of herbivores play a significant role in helping those animals digest plants. However, culturing these fungi in the lab is difficult because they cannot survive in the presence of oxygen and must be grown in sealed containers. A research team led by Michelle O’Malley at the University of California, Santa Barbara, isolated three species of these fungi in feces from goats, horses, and sheep. The enzymes expressed by these fungi work together to break down crude, untreated plant biomass. The research showed that the fungi adapt their enzymes to the different kinds of plant materials eaten by these animals, so that wood, grass, or agricultural waste all can be efficiently digested. Each of the fungi studied was found to contribute in a characteristic way, tailoring their combined action to the particular type of biomass being digested. These findings could help in identifying distinctive enzymes from other anaerobic gut fungi, with potential applications for biomass processing and sustainable biofuel production.

Contacts
PM Contact
Pablo Rabinowicz
Office of Biological and Environmental Research
pablo.rabinowicz@science.doe.gov

PI Contact
Michelle A. O’Malley
Department of Chemical Engineering
University of California, Santa Barbara
momalley@engineering.ucsb.edu

Funding
This work was supported by the Office of Biological and Environmental Research (BER) within the U.S. Department of Energy’s (DOE) Office of Science under Early Career Research Program award DE-SC0010352. A portion of this research was performed under the JGI-EMSL Collaborative Science Initiative and used resources at DOE’s Joint Genome Institute (JGI) and Environmental Molecular Sciences Laboratory (EMSL), which are DOE Office of Science user facilities and sponsored by BER. Authors also acknowledge support from the U.S. Department of Agriculture (Award 2011-67017-20459) and Institute for Collaborative Biotechnologies through grant W911NF-09-0001.

Publications
Solomon, K., et al. "Early-branching gut fungi possess a large, comprehensive array of biomass-degrading enzymes." Science (2016). [DOI: 10.1126/science.aad1431].   (Reference link

Topic Areas:

  • Research Area: DOE Environmental Molecular Sciences Laboratory (EMSL)
  • Research Area: Genomic Analysis and Systems Biology
  • Research Area: Microbes and Communities
  • Research Area: Plant Systems and Feedstocks, Plant-Microbe Interactions
  • Research Area: DOE Joint Genome Institute (JGI)
  • Research Area: Sustainable Biofuels and Bioproducts
  • Cross-Cutting: Early Career

Division: SC-23.2 Biological Systems Science Division, BER

 

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