Monday, November 16, 2009

Direct Conversion Cyanobacteria: Where Will They Get the CO2 to Make Fuels and Plastics?

UCLA researchers have engineered a strain of cyanobacteria that can directly synthesise valuable chemicals isobutanol and isobutyraldehyde from CO2 and sunlight.
Researchers at UCLA led by Dr. James Liao have genetically engineered the common photosynthetic cyanobacterium—Synechococcus elongatus—efficiently to produce isobutyraldehyde and isobutanol directly from CO2. Isobutyraldehyde is a precursor for the synthesis of other chemicals, and isobutanol can be used as a gasoline substitute.

A paper on their work was published online in Nature Biotechnology 15 November. In December 2007, biofuels company Gevo acquired an exclusive license for a method developed by Dr. Liao for modifying the metabolic pathway of E.coli bacteria for the non-fermentative synthesis of higher alcohols including isobutanol, 1-butanol, 2-methyl-1-butanol, 3-methyl-1-butanol and 2-phenylethanol from glucose. Dr. Liao is on Gevo’s scientific advisory board. (Earlier post.)

The researchers modified S. elongatus by incorporating four genes from other bacteria into the structure. The new synthetic pathway begins with the photosynthetic conversion of CO2 to pyruvic acid; three further steps make isobutyraldehyde. Extracting the final product from the mix is a simple process.

The high vapor pressure of isobutyraldehyde allows in situ product recovery and reduces product toxicity. The engineered strain remained active for 8 days and produced isobutyraldehyde at a higher rate than those reported for ethanol, hydrogen or lipid production by cyanobacteria or algae. _GCC
Al Fin supports all viable approaches to biofuels and materials production, but like other methods of "direct conversion" of CO2 to fuels, this process is dependent upon a ready supply of CO2.

Dimwitted greens in academia, media, politics, and environmental organisations, may assume that there is more than enough CO2 in the atmosphere to drive these biofuel efforts. Sadly, CO2 is less than 0.04 % of Earth's gaseous atmosphere. For direct conversion to work, highly concentrated supplies of CO2 will have to be made available.

But if coal mines and power plants are to be shut down under Obamamania energy starvation policies, we may have to import CO2 from China -- using money borrowed from the Chinese.

A good plan, if you are a green rookie of dubious mental depth.

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