Cellulosic Fuel Research Centers on Yellowstone's Warm Water Microbes

(left) Researchers hike Yellowstone National Park, left, on the hunt for microbes that could potentially be used in bioenergy production.

(right) They analyze the samples back home in the lab

Bioenergy from Microscopic Organisms

Oak Ridge National Laboratory microbiologist Tommy Phelps sees the untapped potential of bioenergy in shelves of bottles and beakers containing microscopic organisms that just might hold the elusive bug or enzyme capable of digesting large quantities of plant matter into ethanol.

Phelps's current batch of microbes, stockpiled in dozens of bottles of silt, rocks and soils, was collected from Yellowstone National Park, where the hot springs that draw millions of summertime visitors also nurture microscopic life in their boiling waters. These bugs, in turn, beckon microbiologists like Phelps, who seek a solution to transform Earth's abundant cellulosic sources into a modern energy supply. Yellowstone's warm waters offer the promise of microbes that can rapidly and efficiently degrade cellulose—the woody, leafy matter that makes up plants. Scientists hope to tap the power of these microbes for industrial-scale consolidated bioprocessing of plants, including trees and switchgrass, the species central to the BioEnergy Science Center's research efforts.

BioEnergy Science Center

The hunt for this cellulosic "super bug" is part of a suite of efforts under way at the BioEnergy Science Center, headquartered at Oak Ridge National Laboratory (ORNL). Since being named one of three $135 million Department of Energy bioenergy research centers, researchers at ORNL and its partner institutions have quickly gotten to work.

DOE's ambitious goal is to replace by 2030 one-third of the nation's transportation fuel with cellulosebased sources. At these centers, researchers are carrying out the targeted, fundamental science needed to bridge the gap between the potential of cellulose-based fuels and their reality.

Current microbes and enzymes are relatively slow at attacking plant matter's complicated and protective structure. Researchers will determine precisely the genes involved in the interaction of the microbes and enzymes to break apart cellulose. Other genes responsible for producing undesirable products, such as acetic acids, will be knocked out in the hope of, ultimately, developing the perfect ethanol-manufacturing microbe. Particular enzymes will be isolated as well and genetically analyzed, with a focus on determining the ideal formula of enzyme or microbe and enzyme to serve as the vehicle for cellulosic ethanol production.

Plants with Good Biofuel Sugars

Microbes, however, are just a piece of the puzzle. Other researchers at the Oak Ridge center are going through similar steps to develop plants with qualities most conducive to processing into biofuel. Similar to the microbial work, researchers will analyze thousands of genetically modified switchgrass and poplar tree samples in order to discover and develop the best varieties for ethanol production. As part of the process, the biofeedstock, together with the microbes and the enzymes, will be joined in a complex matrix of analysis and R&D in order to develop the best biofuel recipe.

On the biomass formation side, the partners will produce samples of plant material genetically altered to modify their cell walls for optimum breakdown into usable sugars. Such altered species might feature lower amounts of lignin—the substance that holds cellulose fibers together—or a reduction in the crystallinity of the cellulose. ArborGen and ORNL will be primarily responsible for creating and studying various altered trees, while scientists from the University of Tennessee, the University of Georgia and the Noble Foundation will take the lead in switchgrass research.

Read more at ORNL