Japanese and American scientists are teaming up to boost the production of biofuels with a host of studies that aim to increase understanding of the metabolome.

The metabolome is the group of chemical compounds produced in living cells that are used to generate energy, build structures and other life-sustaining biological processes.

---

The study of metabolites, known as metabolomics, is a piece to the puzzle of understanding how an organism works and behaves under particular circumstances in the same way that genomics brings understanding to the function of genes and proteomics to proteins.

"This is an incredibly important component of cellular function, or organism function, that will allow us to understand how everything fits together," Gregory Warr, a program director at the National Science Foundation, explained to me Thursday.

Currently, scientists can identify and characterize the properties of only a small fraction of the 10,000 to 15,000 metabolites that exist in any given plant. The hope is that increased understanding of these compounds will lead to needed breakthroughs in the production of biofuels.

"By understanding the metabolome, you can understand how one compound gets converted to another, to another, and then perhaps finally to something that's useful as a biofuel," said Warr, who is overseeing the U.S. arm of the Metabolomics for a Low Carbon Society.

The NSF together with the Japan Science and Technology Agency this week announced $12 million in funding for projects in this program.

For example, James Liao, a chemical and biomolecular engineer at the University of California Los Angeles will work with Eiichiro Fukusaki of Osaka University to perform comprehensive metabolic analyses of bacteria and yeast to create genetically engineered bacteria that produce butanol, a biofuel.

Liao told me in an email that the project builds on research we reported on in March where his team altered the metabolic pathways in the bacteria E. coli to more effectively remove nitrogen from groups of amino acids — the building blocks of proteins — to produce alcohols, which are converted to biofuels.

Other projects receiving funding from the program will focus on indentifying and characterizing important metabolites related to biomass and oil production in plants, metabolites used by photosynthetic algae to produce biofuel, and metabolites that thwart attacks by pests and disease.

The projects aren't just about biofuels, Bruce McClure, a NSF program director, told me, but about building understanding on ways to produce the full range of products traditionally made with fossil fuels, including plastics and pharmaceuticals.

Whether or when any of the basic research conducted by the U.S. and Japanese researchers will yield products consumers will see and use in their daily lives in unknown, McClure added.

"What you can predict is that any attempt to develop product lines … will require metabolomic tools and information and intellectual tools that are being supported by this research," he said.

More on biofuels research:

• Bacteria turned into biofuel factories
• China, U.S. companies test-fly biofuel-powered plane
• Eternal youth: A fix for biofuels?
• Biofuel push a bust, report hints
• Is algae biofuel too thirsty?

 

---

John Roach is a contributing writer for msnbc.com. To learn more about him, check out his website. For more of our Future of Technology series, watch the featured video below.

 

 

Innovators from around the world who see power in steaming piles of poop are getting serious money from Microsoft billionaire Bill Gates' foundation to help the world's 2.1 billion urban dwellers without access to sewers live safer, more sanitary and electrified lives.

Grantee Daniel Yeh, a civil and environmental engineer at the University of South Florida, for example, will use the funds to field test an advanced technology that harvests nutrients, energy, and water from wastewater.

---

Known as the NEW generator, it uses anaerobic microorganisms — those that live in the absence of oxygen — to convert organic material into methane, which is natural gas, and a membrane that filters out viruses and bacteria, leaving only water enriched with the nutrients ammonia and phosphorous.

"In the lab, we can already turn wastewater into methane and we can already recover the ammonia and phosphorus into a clean water solution that looks crystal clear, just like tap water," Yeh told me. "The only difference is it has ammonia and phosphorus in it."

Those two nutrients are crucial for growing crops. So this water would be ideal for irrigation, freeing farmers from synthetic ammonia fertilizer, which is energy intensive to make, and phosphorus, which is a finite mined resource, Yeh added.

He and his colleagues will use the $100,000 grant from the Bill and Melinda Gates Foundation to build a field unit and demonstrate the technology at the environmentally progressive Learning Gate Community School in Florida.

Sanitation grants
The project is one of 31 announced Monday by the Seattle-based global health organization for its next generation sanitation technologies as part of a larger round of grants awarded in the Grand Challenges Explorations program.

Untreated fecal sludge contaminates water used for everything from irrigation and bathing to dishwashing and drinking. An estimated 1.6 million children die each year from diarrheal disease, many caused by fecal-oral contamination, according to the Bill and Melinda Gates Foundation.

Among the 30 other projects receiving funding for next generation sanitation technologies are:

• Entrepreneur Jason Aramburu's re:char technology that aims to convert human waste into biochar, which can be used as a replacement for chemical fertilizer or charcoal.
• Environmental and sustainability engineer Zhiyong Ren at the University of Colorado Denver will develop a low-cost and easy-to-operate bioelectric system that uses microbes to breakd waste and convert it to useable electricity.
• Chemist Steven Cobb at Durham University in the United Kingdom aims to develop a "macroporous" scaffold that can support bacterial cells and metal nanoparticles that work together to catalyze conversion of fecal sludge into hydrogen for electricity.
• Roboticist Ioannnis Ieropoulos at the University of Bristol will test the ability of microbial fuel cells to convert urine and sludge into electrical energy while purifying water and killing pathogens.
• And engineer Yinije Tang at Washington University in St. Louis will develop a genetically engineered fungal species that can convert fecal sludge into butanol, a biofuel similar to gasoline.

While we've seen plenty of poop to power projects over the years, all of the ideas fit the Gates Foundation's requirement for proposals designed for low income urban settings, where demand for fecal sludge emptying and treatment are high.

According to the Gates Foundation, the indiscriminate dumping of a truckload of fecal sludge is the equivalent of 5,000 people openly defecating. Harvesting the energy and nutrients in that sludge, noted Yeh, could help solve some of the world's greatest challenges: energy and food.

"Wherever people live, there's wastewater. It's a 24/7 thing," he said. "Why don't we connect the whole picture together and close the loop."

More on poop to power:

• Poop power? Sewage turned into electricity
• Dog poop as power source? City might try it out
• Poop fuels hydrogen cars
• Food waste + fish poop = lettuce

---

John Roach is a contributing writer for msnbc.com. To learn more about him, check out his website. For more from our Future of Technology series, watch the featured video below.

 

Scientists at a government lab in New Mexico have created what appear to be magnetic algae, a breakthrough that could lower the cost of harvesting biofuels from the microscopic plants.

The trick involved transferring to algae a gene from soil bacteria that align themselves with Earth's magnetic field, explained Pulak Nath at the Department of Energy's Los Alamos National Laboratory.

---

"We expressed that gene in algae and it started making what we think are magnetic particles," he told me Friday. "We still have to confirm that, but we could put a magnet next to those algae and see these algae getting attracted."

Magnetism studies
Scientists have studied the soil-living so-called magnetotacic bacteria since the 1970s, primarily as a model to understand how birds are able to migrate thousands of miles each year.

"The whole idea is that they probably have some sort of compass in their brains," Nath said. As a DOE-funded scientist, he turned to those studies in search of an application to cost efficiently harvest algae for biofuels.

Current techniques for extracting algae from the ponds where they are grown include sound waves and the addition of chemicals that cause the algae to clump together, a process known as flocculation.

These techniques account for about 30 percent of the total cost of algae-based biofuel production, Nath noted, and "is one of the limiting steps for algae fuel from becoming cost competitive to fossil fuels." 

Using magnets
Permanent magnets are inexpensive. In theory, algae biofuel systems could flow algae-filled water through a tank lined with the magnets and the algae will get separated from the water, Nath explained.

"And that won't cost us any money in terms of energy input because we are using these permanent magnets and the energy from these permanent magnets — other than the material — is free," he said.

The research, he cautioned, is in the early stages. So far, they've created one species of magnetic algae. Going forward, they will try to transfer the gene to more candidates for algae biofuel production.

The lab's ultimate goal, Nath said, is to take the technique to the proof-of-concept stage and then have someone else "take this technology and take it forward."

To take the research forward, there is incentive in the government push to derive 36 billion gallons a year from a mix of biofuels by the year 2022. 

Other factors that must be tackled for the efficient scale-up of algae biofuels include ways to reduce their need for massive amounts of water and land. 

More stories on algae biofuels:

• Is algae biofuel too thirsty?
• It's pond scum, but algae could be green fuel
• Algae attracts investors, but obstacles remain
• NASA grows algae for biofuel, treats waste

---

John Roach is a contributing writer for msnbc.com. To learn more about him, check out his website. For more information about energy in our ongoing Future of Technology series, watch the video below.

 

The push to wean the biofuel industry off its heavy diet of corn may, ironically, involve transferring a corn gene to non-corn plants such as switch grass, suggests a new study.

The gene, called Corngrass 1, essentially locks the switch grass into a state of perpetual pre-adolescence, explained George Chuck, a plant molecular geneticist at the University of California at Berkeley.

---

"One of the consequences of staying juvenile forever is they don't flower, they don't become sexually mature," he said. 

Instead of burning energy to reproduce, the plants build up starches that are easily degraded into sugars that are fermented to biofuel.

The plants with the gene, Chuck and his colleagues report this week in the Proceedings of the National Academy of Sciences, stored as much as 250 percent more starch in their stems than plants without it.

The breakthrough, the researchers note, could make the production of cellulosic ethanol easier and cheaper than current methods.

In addition, since flowering is prevented with this gene, the risk is reduced that the transgenic plants will contaminate wild plants, one of the concerns about genetically modified crops.

Cellulosic breakthrough?
Researchers are struggling to overcome the expensive pre-treatment process used in the production of cellulosic ethanol, which requires a lot of heat and caustic chemicals, noted Chuck.

"All the treatment just raises the cost of processing the biomass," he said. "Whereas we showed that you can skip the pretreatment if you use our biomass with a lot of starch in it."

In their process, researchers add an enzyme called alpha amylase to degrade the starch to sugars as well as enzymes that break down cell walls, but skip the expensive pre-treatment process entirely.

In theory, this could make cellulosic ethanol more affordable.

Earlier this month, an independent panel appointed by the National Academy of Sciences concluded that the government was unlikely to meet a target of producing 16 billion gallons of cellulosic biofuel a year largely because the technology to produce the fuel cheaply doesn't exist.

Chuck called his team's approach "a first step" in the direction of reaching that goal, though he doesn't know if it can be improved upon and scaled up in time to reach the target.

Nevertheless, he said, the research does show a somewhat ironic way to move away from using corn in producing biofuels, which competes with food for livestock and people.

"From the whole food-vs.-fuel debate, I think the answer may be putting aspects of the food into your biofuel," Chuck said. "Things like starch, building up starch in your biofuel cropland."

More on biofuels:

• Biofuel push a bust, report hints
• Race for better biofuels heats up
• Is algae biofuel too thirsty?
• Venture capitalist eyes cellulosic ethanol

---

John Roach is a contributing writer for msnbc.com.

Unless a major technological breakthrough occurs in the next few years, a U.S. government push to put 16 billions of gallons of cellulosic biofuel into gas tanks annually by 2022 will be a bust, hints a new report. 

The push comes from the congressionally mandated Renewable Fuel Standard. Of the mandated total of 36 billion gallons from a mix of biofuels, the corn-derived ethanol target of 15 billion gallons is doable, the report says. 

But a big part of the standard — 16 billion gallons of cellulosic biofuels from non-edible plant material such as cornstalks and switchgrass — is unlikely to be met, Wallace Tyner, an agricultural economist at Purdue University, told me Tuesday.

---

"The technologies are just not advanced enough to be commercial, they are not cheap enough yet to be commercial, and we are going to have to invest more in R&D if we want to accelerate the pace," he said.

Tyner co-chaired the National Academy of Sciences report requested by Congress on the potential economic and environmental effects of U.S. biofuel policy.

"We're not saying don't do biofuels, we're not saying that it is a bad thing to do, we're just saying it is not going to happen in today's environment unless big things change," he said.

Breakthroughs needed
Currently, no commercially viable biorefineries exist for converting cellulosic biomass to fuel. That's daunting given that it took 30 years to go from zero to 200 plus plants producing more than 15 billion gallons of corn-ethanol, Tyner noted.

"Here we are in 2011 and we have 11 years to get to 2022 and build 16 billion gallons with a technology that's costlier and riskier, a feedstock that's costlier, and it is just not likely to happen," he said.

Breakthroughs are needed in every pathway to produce cellulosic biofuel.

For example, Tyner explained that one technique with a lot backing called fast pyrolysis, which breaks down biomass with heat, produces unstable oils that can't be further refined to gas, diesel, and jet fuel.

Other techniques such as gasification have been done for decades, but it remains too expensive to be commercially viable due to capital costs and catalysts used in the process.

Questionable environmental impacts
And even if technological breakthroughs drive down costs and make cellulosic biofuel commercially viable, a question remains whether or not its use will impact land use or help curb greenhouse gas emissions implicated in global climate change.

Using leftover corn stalks or wood chips from sawmills have no impact on land use and are a net positive for greenhouse gas emissions, Tyner noted, since those materials are already being generated. 

But the impacts other feedstock such as switchgrass and miscanthus is uncertain. Tyner said that preliminary research suggests these crops sequester carbon as they grow, some of which gets locked up in the soil via the root system.

"Those, I think, are going to come out OK," he said, "be we don’t know for sure."

Other biofuel crops, notably corn-derived ethanol, has been lambasted over the years for competing with food for people and livestock as well as having questionable impact on greenhouse gases. 

"For every bushel of corn that you feed to an ethanol plant instead of a hog that hog still has to be fed," Tyner noted, "so more corn or corn substitute has to be grown somewhere else in the world."

This process, the report notes, could involve clearing perennial vegetation such as forests that lock up carbon in trees and soils. Even though biofuels are considered carbon neutral, the loss of forest may offset this gain.

The Environmental Working Group, which has long opposed government mandates for corn-based ethanol, applauded the findings of the new report for showing the negative impact of ethanol subsidies on the environment.

"The new report provides more evidence that corn ethanol production continues to raise food prices around the world and harms the planet by releasing more greenhouse gases than regular gasoline," the group said in statement. 

Promoters of biofuels have long seen corn-derived ethanol as a bridge to more environmentally-friendly cellulosic ethanol, but the new report suggests that bridge is unlikely to be crossed by 2022. 

Further complicating progress on cellulosic ethanol is regulatory uncertainty, which hobbles investment in R&D, noted Tyner. After all, there's not even a guarantee the fuel standard will be around in the future or enforced. 

"You put all those uncertainties into the basket and overlay that with today's financial condition where venture capital is nothing like it was a few years ago and it is going to be hard" to find investors," he said.

More on biofuels:

• Race for better biofuels heats up
• Is algae biofuel too thirsty?
• Venture capitalist eyes cellulosic ethanol
• Energy bill a boon for ethanol, and a challenge

---

John Roach is a contributing writer for msnbc.com.

 

Scientists have successfully added multiple "unnatural" amino acids to a strain of bacteria, a breakthrough on the path to genetically engineered microbes that create useful things for people such as life-saving medicines and biofuels.

"We are adding components to the bug so that the bug can do something that a natural bug usually can't do," Lei Wang at the Salk Institute for Biological Studies told me today. "We are trying to make it do new tricks."

---

Amino acids are molecules built primarily from carbon, hydrogen, oxygen, and nitrogen. They assemble into various shapes and patterns to form the larger proteins. Proteins, in turn, carry out specific biological functions.

All life on Earth relies on a standard set of 20 amino acids. For years, researchers have genetically altered bacteria to perform certain tasks, such as produce the synthetic insulin diabetics use to regulate blood sugar levels. But until now, all such genetic engineering has relied on the 20 natural amino acids.

In the eyes of Wang, the world might be a better place if there were more building blocks available.

"If you can provide more building blocks, then you may be able to generate a new function for the proteins," he said. "And if you can create new functions for the proteins, then you may be able to synthesize new compounds using these proteins."

Examples of the potential compounds include drugs, industrial chemicals, and biofuels. 

Expanded genetic code
To do this, Wang's team created an essentially expanded genetic code for the bacteria, a strain of E. coli, with instructions to use multiple unnatural amino acids in the construction of proteins. 

The technology to put one unnatural amino acid at one place in the DNA has been around for about a decade, Wang said. The problem is that with just one position, "you cannot evolve anything, you cannot produce anything useful," he said. 

This limitation stemmed from that fact that bacteria produce another protein called release factor 1 (RF1) that stops the production of the protein containing the unnatural amino acid. To get around this, Wang's team removed RF1 and altered another protein, RF2, to keep the bug alive in the absence of RF1.

"We can now put unnatural amino acids at multiple places simultaneously and with very, very high efficiency … therefore you significantly increase your chance of generating new protein function and therefore generating new biosynthesis ability," he said. 

Complementary to 'synthetic life'
This approach to creating useful products with genetically enhanced bugs is complementary to efforts such as Craig Venter's well publicized effort to create synthetic lifeforms that could, potentially, produce biofuels, Wang said.

That effort, Wang explained, essentially attempts to reorganize and optimize the natural components of the genome to "make it better." The Salk team's effort gives the bug new building blocks. 

"They sort of help each other out," Wang said of the two approaches. "What they achieve can help us and what we helped achieve here can also help them."

Both approaches along with other efforts to genetically engineer microbes to produce useful products such as butanol may one day allow us to fill up our cars with fuel made by the genetically enhanced bugs or visit the pharmacy for a new class of drugs.

"We are not there yet, but that is exactly what we want to do in the next stage," Wang said.

More stories on engineered bacteria:

• Bacteria turned into biofuel factories
• Bacteria rebuilt to make oil
• It's alive! Artificial DNA controls life
• First synthetic life form holds promise, peril
• Synthetic life could help humans colonize Mars

---

A paper on the findings appear in the Sept. 19 issue of the journal Nature Chemical Biology. 

John Roach is a contributing writer for msnbc.com.

 

Wine and beer drinkers of the world owe a lot of gratitude to yeast, the unicellular fungi that ferment sugars to ethanol, giving the fruit- and grain-based drinks their sought-after alcoholic kick. Now, scientists are closing in on just how and why yeast evolved to do this.

No, it wasn't to get humans drunk.

The special trick of yeast is the ability to ferment sugar to 2-carbon components, in particular ethanol, without completely oxidizing it to carbon dioxide, even in the presence of excess oxygen. This allows yeasts to out-compete other microorganisms.

---

A team of European researchers led by the yeast molecular genetics group at Lund University in Sweden has been trying to reconstruct the evolutionary history of ethanol production. In their latest effort, the team compared the genetic makeup of two wine yeasts: Saccharomyces cerevisiae and Dekkera bruxellensis.

The yeasts separated more than 200 million years ago and are not closely rated. However, the research shows that approximately 100 to 150 million years ago, both yeasts experienced similar environmental conditions and pressure: the appearance of sugar-laden fruits and competition from other microbes. 

The pressure, the researchers found, spurred both lineages, independently and in parallel, to develop the ability to make and accumulate ethanol in the presence of oxygen, and developed resistance to high ethanol concentration, and have been using this ability as a weapon to out-compete other microbes which are sensitive to ethanol.

Surprisingly, the team notes, both yeasts used the same molecular tool, global promoter rewiring, to change the regulation pattern of the expression of respiration-associated genes involved in sugar degradation, which allows ethanol to accumulate. The excess ethanol is toxic to other microbes. 

"Our results now help to reconstruct the original environment and evolutionary trends within the microbial community in the remote past," team leader Jure Piskur, a professor of molecular genetics at Lund University and the University of Nova Gorica, Slovenia, said in a news release. 

"In addition, we can now use the knowledge we have obtained to develop new yeast strains, which could be beneficial for wine and beer fermentation and in biofuel production."

A paper describing the latest research effort appears in Nature Communications.

More stories about yeast and drink:

• Yeast is rising as biofuel booster
• Ancient yeast reborn in modern beer
• Tinkering extends life of organism 10-fold
• Microbes plan ahead, predict future events
• The why behind a wine's bouquet

---

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

 

Biofuel produced from algae, essentially pond scum, has long titillated green energy boosters as a potential big time player in the U.S. renewable fuels portfolio. Now, a-first-of-its-kind look at industrial-scale freshwater farming of algae suggests it could indeed make a sizeable dent in U.S. oil imports, but drain water resources.

Specifically, the U.S. could produce enough of the algae-derived fuel to eliminate 48 percent of the fuel it currently imports for transportation needs, according to researchers at the Department of Energy's Pacific Northwest National Laboratory. But doing so would require 5.5 percent of the land area in the lower 48 states and consume about three times the water currently used to irrigate crops.

---

"The water use is significant," Mark Wigmosta, a hydrologist at the lab who led the study, told me today.

Flat lands
To arrive at the figure, he and colleagues used a geographic information system database to identify land areas that don't compete with agriculture or parks, wetlands, and wildlife habitat. The land had to be relatively flat over about 1,200 acres to support freshwater ponds to grow the algae, a well-tested method to grow algae that the team selected for this baseline study.

The team also factored in 30 years of local climate data to determine how that would impact growth, including factors such as pond temperature and water loss to evaporation. Think of an algae pond like a backyard swimming pool. Water is constantly lost to evaporation — more in a hot, sunny and windy climate; less when it is humid and calm.

A calculation based on all this data led to the 48 percent of transportation imports figure. But the water cost seems like a non-starter for serious consideration of the biofuel. So, the team went looking for ways to reduce water use and found that if the ponds are placed in sunny and humid climates such as the Gulf Coast, the southeastern seaboard, and the Great Lakes, enough fuel can be grown to replace 17 percent of imports and use 25 percent of the water currently used for irrigation.

"So, you've got a significant drop in water use and still have production that is consistent with the renewable fuel targets for 2022," Wigmosta said. The fuel target is set forth in the Energy Independence and Security Act.

"It is still a lot of water," Wigmosta noted, adding the study just takes into account the water lost through evaporation. Additional water is likely to be lost such as during the algae harvest.

While the water loss is significant, the researchers found that algae's water use is comparable to most other biofuel sources.

Considering the gas efficiency of a standard light-utility vehicle, for example, they estimated growing algae uses anywhere between 8.6 and 50.2 gallons of water per mile driven on algal biofuel. In comparison, data from previously published research indicated that corn ethanol can be made with less water, but showed a larger usage range: between 0.6 and 61.9 gallons of water per mile driven.

Several factors — including the differing water needs of specific growing regions and the different assumptions and methods used by various researchers — cause the estimates to range greatly, they found, notes a DOE press release on the study.

Another limiting factor not included in this study is the availability of nutrients for the algae to grow — they eat phosphates and nitrogen-containing compounds, producing the lipids that are converted to biofuel. Future studies will factor this in, Wigmosta told me.

"As we continue to refine this analysis, the number is going to change, but we did want to get a good look at how much land is available and how much water is it going to take," he said.

Non-freshwater algae
Other areas the team will examine include growing algae in non-freshwater, such as saline water that is produced during oil and gas extraction or co-locating a pond next to a water treatment plant. One such pilot project is underway at a waste treatment plant in Rochester, N.Y., led by Eric Lannan, who is getting his masters degree in mechanical engineering at Rochester Institute of Technology.

The project is billed as "doubly green" because the algae clean up the wastewater as they produce biofuel.

"Algae — as a renewable feedstock — grow a lot quicker than crops of corn or soybeans," Lannan said in a news release about the project. "We can start a new batch of algae about every seven days. It’s a more continuous source that could offset 50 percent of our total gas use for equipment that uses diesel."

According to Wigmosta, algae biofuel is still a long ways off from meeting its potential promise as a green fuel of the future, "but it is these kinds of studies that we need to do to really properly evaluate to what extent it can be a player in the renewable fuels portfolio."

A paper describing the research was published online April 13 in the journal Water Resources Research.

More stories on algae biofuel:

• It's pond scum, but algae could be green fuel
• Algae attracts investors, but obstacles remain
• NASA grows algae for biofuel, treats waste
• Green power from algae?
• Plastic made from algae is crazy green 

---

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

Researchers say they've used genetic engineering to create a strain of yeast that can cut the time needed to make ethanol from cellulosic sources in half. It's the latest twist in efforts to fine-tune microbes for "frankenfuel" production.

Like Frankenstein's monster, these ethanol-producing organisms draw upon genetic combinations not found in nature. The scientists reporting their results today in the Proceedings of the National Academy of Sciences started out with common brewer's yeast, then adapted a few tricks used by a different strain of yeast as well as a cellulose-loving fungus.

---

The original yeast, Saccharomyces cerevisiae, is quite good at fermenting glucose, which is currently the primary sugar converted to ethanol in the industrial fermentation process. This is the process by which yeast makes bread rise, and by which yeast turns fruit and grain into wine, beer and other alcoholic beverages. But energy companies would rather make ethanol from cellulosic materials (such as wood waste and switchgrass) rather than from edible products (such as corn and sugar cane). So anything that raises the efficiency of cellulosic ethanol production makes biofuels look more attractive as a long-term energy solution.

One of the big problems is that glucose is only one of the sugars contained in cellulosic material. Brewer's yeast can't ferment the other major type of sugar, known as xylose. "Xylose is a wood sugar, a five-carbon sugar that is very abundant in lignocellulosic biomass but not in our food," Yong-Su Jin, a professor of food science and human nutrition at the University of Illinois, said in a news release. "Most yeast cannot ferment xylose."

Even if a yeast strain can handle xylose fermentation, it won't start in on the xylose until all the glucose is gone. "It's like giving meat and broccoli to my kids," Jin explained. "They usually eat the meat first and the broccoli later."

Jin and his colleagues — including researchers from the University of Illinois, Lawrence Berkeley National Laboratory, the University of California at Berkeley, Seoul National University and the energy company BP — inserted genes from a xylose-converting yeast to give S. cerevisiae the power to turn xylose into ethanol. They also added the capability of a fungus known as Neurospora crassa to work with a precursor of glucose known as cellobiose.

The combination of those two tricks, plus some extra tweaks, enabled the franken-yeast to ferment cellobiose and xylose at the same time. That avoided the glucose vs. xylose, meat vs. broccoli problem.

"If you do the fermentation by using only cellobiose or xylose, it takes 48 hours," Suk-Jin Ha, a postdoctoral researcher at the University of Illinois and the study's lead author, said in today's release. "But if you do the co-fermentation with the cellobiose and xylose, double the amount of sugar is consumed in the same amount of time and [the process] produces more than double the amount of ethanol."

The new yeast strain is at least 20 percent more efficient at converting xylose to ethanol than other strains, Jin said.

He said the potential cost benefits are significant: "We don't have to do two separate fermentations. We can do it all in one pot. And the yield is even higher than the industry standard. We are pretty sure that this research can be commercialized very soon."

This approach builds upon research published in September on the journal Science's website — and one of the researchers involved in that earlier study, Berkeley's Jamie Cate, played a role in the newly published study as well. As I noted back in September, other researchers are working on different ways to use yeast for producing biofuel. Bottom line? If cellulosic ethanol ever becomes a major part of America's energy equation, it's sounding as if genetically modified yeast will be the key that turns the ignition.

But what do you think? How will biofuel fit in alongside fossil fuels, solar and wind energy, nuclear power and other options? Feel free to discuss America's energy future in the comment space below.

---

In addition to Jin, Ha and Cate, the authors of the PNAS paper, titled "Engineered Saccharomyces Cerevisiae Capable of Simultaneous Cellobiose and Xylose Fermentation," include Jonathan Galazka, Soo Rin Kim, Jin-Ho Choi, Xiaomin Yang, Jin-Ho Seo and N. Louise Glass. The research was supported by the Energy Biosciences Institute, a BP-funded initiative.

Join the Cosmic Log corps by clicking the "like" button for our Facebook page or following my updates on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto."