A Better Bug to Make Cellulosic Ethanol  

Technology Review has an article on some new research into cellulosic ethanol - Better Bug to Make Cellulosic Ethanol.

New genetically modified bacteria could slash the costs of producing ethanol from cellulosic biomass, such as corn cobs and leaves, switchgrass, and paper pulp. The microbes produce ethanol at higher temperatures than those used to produce yeast, which is currently employed to ferment sugar into the biofuel. The higher temperature more than halves the quantity of the costly enzymes needed to split cellulose into the sugars that the microbes can ferment. What's more, while yeast can only ferment glucose, "this microorganism is good at using all the different sugars in biomass and can use them simultaneously and rapidly," says Lee Lynd, an engineering professor at Dartmouth College, who led the microbe's development.

Most of the ethanol produced in the United States is made from corn. But making the biofuel from corn takes a lot of energy and competes with agricultural uses of the crop. Making fuel from cellulosic plant matter has the potential to be much more sustainable. However, cellulosic-ethanol production is still too expensive to be commercially competitive with corn ethanol.

Turning cellulose into ethanol involves two steps: using enzymes to break complex cellulose into simple sugars such as glucose, and then using yeast to ferment the sugar into ethanol. Both steps add to the price of ethanol. Enzymes can add about 50 cents to a gallon of ethanol. And the second step is relatively expensive because conventional yeast ferments only glucose, although biomass contains five different sugars, linked to form cellulose and hemicellulose in plant cell walls. (Cellulose is a long chain of glucose molecules, while hemicellulose contains all five sugars.) "You really need to be able to convert [all] these sugars into ethanol in order to make it economical, to get a good enough yield," says Bruce Dien, a biochemical engineer doing ethanol research at the USDA's Agricultural Research Service.

Lynd wants to create microbes that would do it all: efficiently break down the cellulose and hemicellulose, and then ferment all the resulting sugars. Lynd, a cofounder of Mascoma, is working with colleagues at the startup, based in Cambridge, MA, to develop a simple one-step process for making cellulosic ethanol. In the combined process, a mixture of biomass and the microbes would go into a tank, and ethanol would come out.

The new microbe, presented in this week's PNAS, is a crucial step toward such a combined process. The bacteria can break down hemicellulose into its five constituent sugars, which they ferment efficiently. To increase the bacteria's ethanol yield, Lynd and his colleagues knocked out the gene that results in organic acid formation. ...

Second generation biofuel company Amyris Biotechnologies features in this years "GoingGreen 100" from AlwaysOn (which bizarrely now includes some "clean" coal companies in its "clean energy" category, which is a sufficiently shameful act that I'm tempted to ignore them entirely in future) - The 2008 GoingGreen 100.

Investment and public interest in cleantech continues to grow in the face of record gas prices and increased concern for the environment and global warming. With that backdrop, AlwaysOn presents the second annual GoingGreen 100 Top Private Companies list, featuring leading private companies in cleantech.

The fact that there are 17 solar companies on the list highlights the continued importance of that sector to the industry. Solar companies continue to lead the race for investment dollars, with all areas of the solar industry—PVs, solar cells, concentrated solar plants—actively receiving investments this year. ...

An increased number of companies on the list are moving out of beta testing and into product development. This trend is particularly evident in the Biofuels category, where the growth in next-generation biofuels is beginning to drive to the commercialization stage. From a funding perspective, large rounds of VC funding are narrowing the gap between project financers looking for proven technology and emerging companies wanting to build plants.

The Energy Efficiency and Management category is a very active investment area. The category winner, Silver Spring Networks, provides intelligent utility networking using open standards. Naverus, who is redefining the airspace navigation systems, is another company that is a significant player in this segment of the industry.

An interesting development in the Green Automobiles and Transportation category is the changing attitude of investors. Over the past year, investors have shifted their focus from building car companies and brands to improving engines. Increased public interest in energy efficient “clean” cars may be driving this shift.

The Energy Storage Systems category is commonly identified as a major opportunity of cleantech, with investors actively seeking the solution for energy storage. The category winner, Premium Power, manufactures regenerative fuel-cell power systems based on the company’s proprietary Zinc-Flow advanced energy storage technology.

In the 2008 GoingGreen list, the categories of nanotech and materials were separated—we now have a Green Nanotech and Synthetic Genomics category and a Green Materials, Green Buildings category. The companies in the Green Nanotech and Synthetic Genomics category are expected to have some of the most profound effects on the petrochemical and fuels industries. Our overall list winner, Synthetic Genomics, falls into this category. Serious Materials, our Green Materials, Green Buildings category winner, leads the industry with green replacement products for the built environment. Integrity Block is also an emerging player in this industry with its concrete block replacement.

The spotlight continues to be directed on cleantech and will remain in place until the quest for a “greener” world is realized. The companies featured on the GoingGreen list will help move us closer to achieving this goal.