Featured Research

from universities, journals, and other organizations

Bioenergy potential unearthed in leaf-cutter ant communities

Date:
June 14, 2013
Source:
University of Wisconsin-Madison
Summary:
As spring warms up Wisconsin, humans aren't the only ones tending their gardens. Colonies of leaf-cutter ants cultivate thriving communities of fungi and bacteria using freshly cut plant material.

Illustration of the leaf-cutter ant Atta cephalotes in its fungus garden habitat. The variation in texture between the top and bottom strata represents the different stages of biomass degradation occurring in each layer of the fungus garden.
Credit: Cara Gibson

As spring warms up Wisconsin, humans aren't the only ones tending their gardens.

At the University of Wisconsin-Madison Department of Bacteriology, colonies of leaf-cutter ants cultivate thriving communities of fungi and bacteria using freshly cut plant material.

While these fungus gardens are a source of food and shelter for the ants, for researchers, they are potential models for better biofuel production.

"We are interested in the whole fungus garden community, because a lot of plant biomass goes in and is converted to energy for the ants," says Frank Aylward, a bacteriology graduate student and researcher with the Great Lakes Bioenergy Research Center.

Aylward is the lead author of a study identifying new fungal enzymes that could help break down cellulosic -- or non-food -- biomass for processing to fuel. His work appears on the cover of the June 15 issue of the journal Applied and Environmental Microbiology.

"All the enzymes that we found are similar to known enzymes, but they are completely new; no one had identified or characterized them until now, " Aylward says.

Building on Aylward's previous study of these gardens, the researchers relied on genome sequencing provided by the U.S. Department of Energy Joint Genome Institute (JGI) and support from Roche Applied Science's 10 Gigabase Grant Program to understand the unique roles of fungi and bacteria. In addition to sequencing the genome of Leucoagaricus gongylophorous, the fungus cultivated by leaf-cutting ants, the researchers looked at the genomes of entire, living garden communities.

"We really tried as thoroughly as possible to characterize the biomass degrading enzymes produced," Aylward says. "Identifying all these new enzymes really opens the door to technological applications, because we could potentially mix and match them with others that we already know about to achieve even better biomass degradation."

In a symbiotic relationship, L. gongylophorous provides food for the leaf-cutter ant Atta cephalotes by developing fruiting bodies rich in fats, amino acids and other nutrients. To fuel production of these fruiting bodies, the fungus needs sugar, which comes in the form of long cellulose molecules packed inside the leaf clippings the ants deliver. To get at the sugars, the fungus produces enzymes that break the cellulose apart into glucose subunits.

After sequencing the L. gongylophorous genome, the researchers noticed that the fungus seemed to be doing the lion's share of cellulose degradation with its specialized enzymes. However, they also realized that it was by no means working alone: in fact, the gardens are also home to a diversity of bacteria that may help boost the fungus's productivity.

"We think there could potentially be a division of labor between the fungus and bacteria," says Garret Suen, co-author of the study and a UW-Madison assistant professor of bacteriology and Wisconsin Energy Institute researcher.

The researchers have a few leads in their investigation of the mysterious role of bacteria in leaf-cutter ant communities, which they are pursuing in collaboration with JGI. In addition to providing nitrogen and key vitamins, the bacteria appear to help the fungus access energy-rich cellulose by breaking apart other plant polymers that encase it, such as hemicellulose.

Accessing and deconstructing cellulose is also the goal of GLBRC researchers, who want to ferment the stored sugars to ethanol and other advanced biofuels. Enzymes such as those of the leaf-cutting ants' fungus specialize in breaking down leaves, but understanding how they work in the context of the ant community could help researchers create similar methods for processing cellulosic biofuel feedstocks, such as corn stalks and grasses.

The researchers are discovering, however, that both the beauty and the challenge of the leaf-cutter ant garden lie in its complexity. A peek into UW-Madison's resident colony in the Microbial Sciences Building reveals a metropolis of brown insects bustling around the pale, pitted surface of the fungus garden, many with leaf sections held aloft. The strong resemblance to a small city drives home the point that energy production in such a meticulously coordinated system would be difficult to replicate in a lab or a bio-refinery.

"In an industrial setting, you need a system that's reproducible, sustainable, controlled -- and that produces a consistent level of ethanol," Suen says.

A potential alternative to re-creating these natural processes is to extract, replicate and purify biomass-degrading enzymes synthetically. New enzymes could be added to known combinations and tested for their ability to break down biofuel feedstocks. However, this process can be time-consuming and costly.

To put their findings in perspective, the researchers plan to study other insects in addition to ants, including certain species of termites and beetles, which also act as gardeners in fungal communities. They hope that a better understanding of these complex systems will help them share their biomass-degrading secrets with bioenergy researchers.

"It's difficult to think that we can actually find a process that improves on nature," says Aylward, "so it probably makes sense to learn from it."


Story Source:

The above story is based on materials provided by University of Wisconsin-Madison. The original article was written by Celia Luterbacher. Note: Materials may be edited for content and length.


Journal Reference:

  1. F. O. Aylward, K. E. Burnum-Johnson, S. G. Tringe, C. Teiling, D. M. Tremmel, J. A. Moeller, J. J. Scott, K. W. Barry, P. D. Piehowski, C. D. Nicora, S. A. Malfatti, M. E. Monroe, S. O. Purvine, L. A. Goodwin, R. D. Smith, G. M. Weinstock, N. M. Gerardo, G. Suen, M. S. Lipton, C. R. Currie. Leucoagaricus gongylophorus Produces Diverse Enzymes for the Degradation of Recalcitrant Plant Polymers in Leaf-Cutter Ant Fungus Gardens. Applied and Environmental Microbiology, 2013; 79 (12): 3770 DOI: 10.1128/AEM.03833-12

Cite This Page:

University of Wisconsin-Madison. "Bioenergy potential unearthed in leaf-cutter ant communities." ScienceDaily. ScienceDaily, 14 June 2013. <www.sciencedaily.com/releases/2013/06/130614125647.htm>.
University of Wisconsin-Madison. (2013, June 14). Bioenergy potential unearthed in leaf-cutter ant communities. ScienceDaily. Retrieved April 16, 2014 from www.sciencedaily.com/releases/2013/06/130614125647.htm
University of Wisconsin-Madison. "Bioenergy potential unearthed in leaf-cutter ant communities." ScienceDaily. www.sciencedaily.com/releases/2013/06/130614125647.htm (accessed April 16, 2014).

Share This



More Plants & Animals News

Wednesday, April 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Outbreak Now Linked To 121 Deaths

Ebola Outbreak Now Linked To 121 Deaths

Newsy (Apr. 15, 2014) The ebola virus outbreak in West Africa is now linked to 121 deaths. Health officials fear the virus will continue to spread in urban areas. Video provided by Newsy
Powered by NewsLook.com
In Washington, a Push to Sterilize Stray Cats

In Washington, a Push to Sterilize Stray Cats

AFP (Apr. 14, 2014) To curb the growing numbers of feral cats in the US capital, the Washington Humane Society is encouraging residents to set traps and bring the animals to a sterilization clinic, after which they are released.. Duration: 02:29 Video provided by AFP
Powered by NewsLook.com
After Attack, Officials Kill 5 Bears in Florida

After Attack, Officials Kill 5 Bears in Florida

AP (Apr. 14, 2014) Florida wildlife officials say they have killed five bears following an attack on a woman in a suburban subdivision in central Florida. Forty-five year-old Terri Frana was attacked by a large bear in her driveway Saturday. (April 14) Video provided by AP
Powered by NewsLook.com
Uruguay Opens Its First Cannabis Library

Uruguay Opens Its First Cannabis Library

AFP (Apr. 13, 2014) Uruguay opened its first Cannabis Library in Montevideo on Saturday, where people can come and read books on cannabis or take classes on how to grow the plant or even how to cook with it. Duration: 01:20 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins