In the search for renewable alternatives to gasoline, heavy alcohols such as isobutanol are promising candidates. Not only do they contain more energy than ethanol, but they are also more compatible with existing gasoline-based infrastructure. For isobutanol to become practical, however, scientists need a way to reliably produce huge quantities of it from renewable sources. MIT chemical engineers and biologists have now devised a way to dramatically boost isobutanol production in yeast, which naturally make it in small amounts. They engineered yeast so that isobutanol synthesis takes place entirely within mitochondria, cell structures that generate energy and also host many biosynthetic pathways. Using this approach, they were able to boost isobutanol production by about 260 percent. Though still short of the scale needed for industrial production, the advance suggests that this is a promising approach to engineering not only isobutanol but other useful chemicals as well, says Gregory Stephanopoulos, an MIT professor of chemical engineering and one of the senior authors of a paper describing the work in the Feb. 17 online edition of Nature Biotechnology.
Following the same research path, proteins can help scientists discover the best quality biomass which in turn can produce the best biofuel:
New protein probes are now helping scientists find the best biomass-to-biofuel production enzymes that nature has to offer. Turning biomass into biofuel hinges on the breakdown of the energy-rich primary component of plant matter, cellulose. Cellulose is a polysaccharide, or ‘many sugars’ bonded together. For biofuel production, the bonds between the many sugars must be broken so that those sugars can then be further processed, for example, fermented to make ethanol. But breaking these bonds is no small feat because they are strong. The best known candidate for this job? A group of microbe-made enzymes called glycoside hydrolases, or GHs.
It is also challenging that the production of new enzymes can “transform” plants to be more biofuel friendly:
Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have created a new enzyme and demonstrated its potential ability to interfere with the production of lignin, a key cell-wall component in plants. This approach to enzyme engineering, described in the January 1, 2010, issue of the Journal of Biological Chemistry (available online December 25, 2009), could be used to further understand the mechanisms of lignin biosynthesis, and may lead to the production of plants that are easier to convert to biofuels. “Increasing the ‘digestibility’ of plant matter is one main approach to making plants a viable alternative energy source,” said Brookhaven biochemist Chang-Jun Liu, lead author on the paper. “Our group has been working to achieve that goal by elucidating the catalytic mechanisms of plant enzymes, and then using that knowledge and the tools of molecular biology and protein engineering to influence the way plant cell walls are constructed.” Their main targets have been enzymes that synthesize key cell-wall components, such as lignin. Plants with less lignin in their cell walls are easier to break down and convert to fuel products.
In a broader sense, the World Economic Forum has presented a list of the top 10 emerging technologies which can help biofuel production:
The World Economic Forum’s Global Agenda Council on Emerging Technologies identifies the top 10 most promising technology trends that can help to deliver sustainable growth in decades to come as global population and material demands on the environment continue to grow rapidly. These are technologies that the Council considers have made development breakthroughs and are nearing large-scale deployment.
1. OnLine Electric Vehicles (OLEV)
2. 3-D printing and remote manufacturing
3. Self-healing materials
4. Energy-efficient water purification
5. Carbon dioxide (CO2) conversion and use
6. Enhanced nutrition to drive health at the molecular level
7. Remote Sensing
8. Precise drug delivery through nanoscale engineering
9. Organic electronics and photovoltaics
10. Fourth-generation reactors and nuclear-waste recycling.
Finally, the sceintific-research goal to transform plants for being more effective in biofuel, offers the only viable solution to sustainable development.