The study, in the journal Science, tackles a major barrier to the development of more affordable and environmentally sustainable biofuels. Rather than relying on the fermentation of simple sugars in food crops such as corn, beets or sugar cane (which is environmentally costly and threatens the food supply) researchers are looking for better ways to convert the leaves and stems of grasses or woody plants to liquid fuel. These "second-generation" biofuels ideally will be "carbon neutral," absorbing as much carbon dioxide from the atmosphere as is emitted in their processing and use.
But breaking down and releasing the energy in the plant cell wall is no easy task.
"The problem with second-generation biofuels is the problem of unlocking the soluble fermentable sugars that are in the plant cell wall," said University of Illinois animal sciences professor Roderick Mackie, an author on the study whose research into the microbial life of the bovine rumen set the stage for the new approach. "The cow's been doing that for millions of years. And we want to examine the mechanisms that the cow uses to find enzymes for application in the biofuels industry."
In previous studies beginning in 2008, Mackie and Washington State University professor Matthias Hess (then a postdoctoral researcher at the U.S. Department of Energy Joint Genome Institute in California) used a decades-old technique for studying ruminant nutrition. They placed small, mesh bags containing either milled alfalfa or switchgrass through a cannula (a permanent, surgically installed portal) into the cow rumen and examined the microbes that adhered to each plant type after two or three days. Visual and chemical analyses showed that microbes in the rumen were efficiently breaking down both types of plant matter, with a different community of microbes attacking each plant type.
This and later experiments proved that the technique could help scientists find the microbes in the cow rumen that were most efficient at degrading a particular type of plant matter, said Mackie, who is a professor in the U. of I. Institute for Genomic Biology.
In the new study, the researchers focused on switchgrass, a promising biofuels crop. After incubating the switchgrass in the rumen for 72 hours, researchers conducted a genomic analysis of all of the microbes that adhered to switchgrass. This "metagenomic" approach, led by Edward Rubin, of the DOE Joint Genome Institute and the Lawrence Berkeley National Laboratory, analyzed all the genes in all the microbes present in a sample, rather than one at a time. This gave a more accurate picture of the processes in the rumen that make plant degradation possible, Mackie said.
"Bacteria are microbes," he said. "They don't live alone. They live in consortia, and they all contribute to the functioning and the services provided."
Using a variety of techniques, the researchers sequenced and analyzed the total DNA in the sample, a huge undertaking that allowed them to identify 27,755 potential "carbohydrate-active" genes. They cloned some of these genes into bacteria, and successfully produced 90 proteins of interest. They found that 57 percent of these proteins demonstrated enzymatic activity against cellulosic plant material.
The researchers also were able to assemble the genomes of 15 previously "uncultured" (never before grown in a lab) microbes, said Hess, who is first author on the new study. Several techniques, including sequencing the genomes of individual cells and comparing those to the assembled genomes, validated this approach, he said.
These results suggest that the bovine rumen is one of the best microbial habitats to explore for sources of plant-degrading enzymes, the researchers reported.
The research team also included scientists from the DOE Joint Genome Institute, the University of California at Berkeley and Illumina Inc. The BP-sponsored Energy Biosciences Institute funded the research carried out at Illinois.
Editor's notes: To reach Roderick Mackie, call 217- 244-2526; e-mail email@example.com.
The paper, "Metagenomic Discovery of Biomass-Degrading Genes and Genomes From Cow Rumen," is available from the U. of I. News Bureau.
Diana Yates | EurekAlert!
Make way for the mini flying machines
21.03.2018 | American Chemical Society
New 4-D printer could reshape the world we live in
21.03.2018 | American Chemical Society
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
21.03.2018 | Physics and Astronomy
21.03.2018 | Materials Sciences
21.03.2018 | Life Sciences