A new bacterium, a cyanobacterium that is energized by sunlight and excretes the sugars glucose and sucrose with some cellulose has been created by Dr. R. Malcolm Brown and Dr. David Nobles at the University of Texas at Austin. The life of the bacteria based in the production of cellulose and the sugars could be significant if scaling to industrial dimensions is workable.
Cyanobacteria would be very inexpensive as the growth medium uses salty water not suitable for human use or crop production and the best sunlit locations would not be major crop areas. The sugars and cellulose can be continuously harvested, as they are the excrement, without the bacteria itself being harvested as in algae production. The research also revealed that cyanobacteria can fix atmospheric nitrogen without a petroleum based fertilizer input.
The research was recently published in the journal Cellulose with the press release coming out April 23, 2008.
Dr. Nobles made the new cyanobacteria (aka blue green algae) by inserting a set of cellulose making genes from a non-photosynthesizing vinegar bacterium Acetobacter Xylinum a known prolific cellulose producer. The gene blending results in the production of a near pure, gel like form of cellulose, which is easily broken down to glucose. This offers a way to avoid the cellulose trap in larger plants where the cellulose is mixed with the hard lignin and other organic compounds. Dr. Nobles says he was surprised to find that the cyanobacteria he designed also secreted large amounts of the sugars and the sugars can be harvested directly. Serendipity, indeed.
The big dollars for ethanol processes today in the cellulosic field is in the specialized enzymes and mechanical crushing to release and break down the cellulose into the sugars. The bacteria approach solves a large part of the process cost to prepare a feedstock for alcohol production, no forests or special crops need be grown to produce the cellulose.
The gentlemen and the press release writer have done some “napkin” numbers of their own. They figure that to displace all oil products for transportation to ethanol from corn would require 820,000 square miles, or twice the area of the entire corn growing Midwest. In their hypothesis the bacteria as it is now productive in the lab would need a sunlit area half that size, or about the area of the entire Midwest. With a caution that there is much work yet to do, working with laboratory scale bioreactors has shown a potential of 17 fold increases in productivity. If that can be achieved at industrial scale, the land area needed would be 3.5% of the Midwest or 28,700 square miles. For scale, think of that as about twice the area of the top 100 area sized cities in the U.S. or about 110% of the area of West Virginia.
Humble to a dignified and classy conclusion, Dr. Brown offers, “There will be many avenues to become completely energy independent, and we want to be part of the overall effort.” That’s called confidence and reassurance for the rest of us.
Dr. Brown and Dr. Noble are well on the way to researching the best methods to scale up efficient and cost effective production of the cyanobacteria. Two patent applications, 20080085520 and 20080085536 have been published by the Patent and Trademark Office.
Combined with algae production and driven to high productive efficiency this research offers a comparatively small land area to a large return of fuel feedstock. Overlooked in the press release is the source of the carbon, most likely airborne CO2. That makes this a recycling of atmospheric carbon, another motivator for many, to press on with research. Now if there would be a solution to take the sugars on to the four-carbon alcohol butanol the payoff would be beyond great.
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