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| Science & Technology |
| Geneticlly Engineered Yeast for Ethanol produced 50 percent more tolerates higher proof |
| 2007-01-04 |
| Scientists from Whitehead Institute and MIT have engineered yeast that can improve the speed and efficiency of ethanol production, a key component to making biofuels a significant part of the U.S. energy supply. Currently used as a fuel additive to improve gasoline combustibility, ethanol is often touted as a potential solution to the growing oil-driven energy crisis. There are significant obstacles to producing ethanol. One is that high ethanol levels are toxic to the yeast that ferments corn and other plant material into ethanol. By manipulating the yeast genome, the researchers have engineered a new strain of yeast that can tolerate elevated levels of both ethanol and glucose, while producing ethanol faster than un-engineered yeast. The work will be reported in the Dec. 8 issue of Science. Fuels such as E85, which is 85 percent ethanol, are becoming common in states where corn is plentiful; however, their use is mainly confined to the Midwest because corn supplies are limited and ethanol production technology is not yet efficient enough. Boosting efficiency has been an elusive goal, but the researchers, led by Hal Alper, a postdoctoral associate in the laboratories of MIT chemical engineering professor Gregory Stephanopoulos and Whitehead Member Gerald Fink, took a new approach. The team targeted two proteins that belong to a class of proteins called transcription factors. These proteins typically control large groups of genes, regulating when these genes are turned on or shut off. When the researchers altered a transcription factor called the TATA-binding protein, it caused the over-expression of at least a dozen genes, all of which were found to be necessary to elicit an improved ethanol tolerance. As a result, that strain of yeast was able to survive high ethanol concentrations. In addition, this altered strain produced 50 percent more ethanol during a 21-hour period than normal yeast. The prospect of using this approach to engineer similar tolerance traits in industrial yeast could dramatically impact industrial ethanol production, a multi-step process in which yeast plays a crucial role. First, cornstarch or another polymer of glucose is broken down into single sugar (glucose) molecules by enzymes, then yeast ferments the glucose into ethanol and carbon dioxide. Last year, four billion gallons of ethanol were produced from 1.43 billion bushels of corn grain (including kernels, stalks, leaves, cobs, husks) in the United States, according to the Department of Energy. In comparison, the United States consumed about 140 billion gallons of gasoline. |
| Posted by:3dc |
| #15 Burning a liquid hydrocarbon produces about 8 times the mass of the hydrocarbon in H2O and CO2. Since H2O and CO2 are both greenhouse gases, it looks like some scientifically ignorant greenie (is there any other kind) has replaced 'x tonnes of greenhouse gases' with 'x tonnes of CO2'. |
| Posted by: phil_b 2007-01-04 20:30 |
| #14 Ed, that's about what I thought although I figured it was 2.66 based on the atomic weights of C & O. 1 C from the fuel, two O from the air. BUT, the claim was 9+ tons of CO2. Using your figure of 3x that means that you would have to burn at least 3 tons of fuel. Which at 20 mpg means that you would drive ~50k mpy. This really does reek of Lancet math, since I didn't even take into account the fact that not all C in the fuel turns into C02. |
| Posted by: AlanC 2007-01-04 14:28 |
| #13 Ethanol is viable because of government subsidies. It's useful as an oxygenator, but as has low energy density and requires too much energy inputs to produce just to burn in internal combustion engines. Alcohol (methanol) will be useful when fuel cells are in wide use. |
| Posted by: ed 2007-01-04 13:54 |
| #12 Around 3 times the weight of CO2 is produced by burning any hydrocarbon. |
| Posted by: ed 2007-01-04 13:46 |
| #11 AlanC, You used non-Lancet maths. |
| Posted by: Bright Pebbles in Blairistan 2007-01-04 13:12 |
| #10 Somewhat off topic, but relevant. Yesterday Instapundit had a humorous article about greenie bumper stickers on gas guzzlers. One piece of the info struck me as wierd. There was a statement that a car getting 20 MPG would produce 9 tons of CO2 / year. Now, by my figures (at 6 lbs / gall of gas) that car going 12k miles/yr will only use about 3600 lbs of fuel and produce 18,000 lbs of CO2. Could that be right? I understand that you are adding O2 to the Carbon but that doesn't seem sufficient to be a factor or 5 increase. 2.5 maybe. What did I get wrong? Thanks AlanC |
| Posted by: AlanC 2007-01-04 11:24 |
| #9 This doesn't make sense. Why use yeast, that requires sugars, to produce ethanol, instead of algae, that only needs sunlight, and consumes CO2, to make biodiesel and ethanol? http://web.mit.edu/erc/spotlights/alg-all.html "For the past year, exhaust from MIT’s main power plant has been bubbling up through tubes of algae soup. The result? A dramatic cut in carbon dioxide (CO2) emissions—and abundant algae that can be turned into biofuel for the power plant or a diesel vehicle. Utility companies have been watching field trials of the algae-soup system with keen interest, hoping to combine low-cost exhaust cleanup with renewable-fuel production." My point is, while yeast can give you more ethanol, and faster, it does so at much greater cost, and creates considerable waste. If you have an economic need for a yeast ethanol generator, then it should at least be in tandem with an algae bio-diesel generator, that also makes some ethanol as a bi-product. On the grand scale, we have already mastered the automobile diesel engine. It is an efficient engine and takes little re-tooling for an automobile plant to convert from gasoline engines to diesel engines. However, ethanol has only half the energy of gasoline, we don't have a very good engine for it yet, and it may need so rather nasty fuel additives to make it work well. Why bother? Go diesel. |
| Posted by: Anonymoose 2007-01-04 10:55 |
| #8 don't tell these guys either! http://www.chimay.com/en/chimay_triple_219.php |
| Posted by: Zarquon Pebbles in Blairistan 2007-01-04 08:26 |
| #7 "...then yeast ferments the glucose into ethanol and carbon dioxide." This bit simply isn't true. As any homebrewer worth his malt could tell you, yeast at first RESPIRES producing water and carbon dioxide until all the oxygen in the fermentation vessel is used up. Only then does it start FERMENTATION (an anaerobic process) which results in water and alcohol. Any fizzy beverage is one which has a small amount of oxygen and sugar added during a later stage to produce a small bit of respiration (and carbon dioxide), or is pressure carbonated. The good news in the article is the strain of yeast which ferments to a higher level of alcohol before it shuts down. Most beer yeasts quit at 6-8%, better wine yeasts at 14-16%. If you could even increase this to 25%, that's a significant increase in productivity. I wonder if the bourbon industry know about this...... |
| Posted by: no mo uro 2007-01-04 06:47 |
| #6 Supposedly making alcohol from grain generates no more net CO2 than was present when the seed grain sprouted. |
| Posted by: Anguper Hupomosing9418 2007-01-04 06:25 |
| #5 When the researchers altered a transcription factor called the TATA-binding protein, it caused the over-expression of at least a dozen genes, all of which were found to be necessary to elicit an improved ethanol tolerance. As a result, that strain of yeast was able to survive high ethanol concentrations. I've overexpressed in my genes when I had a low tolerance too. ...then yeast ferments the glucose into ethanol and carbon dioxide. What's this gonna do for global warming? How's this work for Methenol? Wild Turkey 201? |
| Posted by: Skidmark 2007-01-04 04:49 |
| #4 4 billion gallons produced last year, produce an extra 136 billion gallons & we can kiss Islamic oil goodbye. |
| Posted by: Anguper Hupomosing9418 2007-01-04 01:56 |
| #3 And the hard-fighting, hard-drinking, hard-lovin' "Wild Geese" of Ireland, or PETER of FAMILY GUY, thank you for the information. |
| Posted by: JosephMendiola 2007-01-04 01:01 |
| #2 > By manipulating the yeast genome, the researchers have engineered a new strain of yeast that can tolerate elevated levels of both ethanol and glucose They just gene sequenced everyone that could survive 10 red-bull and vodkas. |
| Posted by: Bright Pebbles in Blairistan 2007-01-04 00:58 |
| #1 TATA-binding I've seen pictures of that. Probably very painful. |
| Posted by: Jackal 2007-01-04 00:33 |