Clostridium acetobutylicum is a commercially valuable bacterium, first isolated from corn in 1912 by Clostridium acetobutylicum is a commercially valuable bacterium, first isolated from corn in 1912 by HYPERLINK "http://en.wikipedia.org/wiki/Chaim_Weizmann" Chaim Weizmann. It is a HYPERLINK "http://en.wikipedia.org/wiki/Gram_positive" Gram-positive, sporulating, HYPERLINK "http://en.wikipedia.org/wiki/Anaerobic_organism" obligate anaerobe capable of producing acetone, butanol (Biobutanol), and ethanol (A.B.E fermentation) from a variety of carbon sources (e.g. starch). Original interest lay in its butanol production, used in the manufacture of synthetic rubber. But wartime shortages focused the interest on acetone which was used in the production of cordite, a propellant for guns and rockets. Until the 1960s, commercial fermentation of C. acetobutylicum for these solvents remained economically competitive with petrochemical production. It then went into decline, but rising interest in environmentally friendly energy sources and depleting world crude oil reserves puts Biobutanol back into the spotlight as part of an arsenal of alternative HYPERLINK "http://en.wikipedia.org/wiki/Biofuel" biofuels.

ADVANTAGES

HYPERLINK "http://www.esru.strath.ac.uk/EandE/Web_sites/02-03/biofuels/what_biodiesel.htm" Biodiesel and HYPERLINK "http://www.esru.strath.ac.uk/EandE/Web_sites/02-03/biofuels/what_bioethanol.htm" bioethanol are already in production and play their role, but HYPERLINK "http://www.butanol.com/" biobutanol can boast several advantages:

Higher energy content than bioethanol.

Less volatile than bioethanol and therefore safer to use.

Can be used at 100% in unmodified petrol-powered cars with HYPERLINK "http://www.butanol.com/" increased performance.

Easliy transported through existing fuel pipelines.

Less sensitive to low temperatures, making it a serious contender as an alternative aviation fuel.

CHALLENGES

At the present time biofuels cannot substitute for current fossil fuel use. The major constraints are land surface available for growing the crops, crop yield, energy conversion efficiency and economics. So the challenge to Science is on to:

Find a cheap, plentiful, reliable raw material. C. acetobutylicum can digest HYPERLINK "http://en.wikipedia.org/wiki/Whey" whey, HYPERLINK "http://en.wikipedia.org/wiki/Sugar" sugar, HYPERLINK "http://en.wikipedia.org/wiki/Starch" starch, HYPERLINK "http://en.wikipedia.org/wiki/Lignin" lignin, and HYPERLINK "http://en.wikipedia.org/wiki/Cellulose" cellulose directly into butanol. Thus there are therefore many avenues to explore.

Increase the conversion efficiency by genetically modifying C. acetobutylicum to divert production from acetone and ethanol to butanol.

Develop a cost effective continuous removal system to replace traditional distillation.

With such potential for development it is easy to see why the smart money ( HYPERLINK "http://www.abf.co.uk/media/press_release.asp?pr=20060620_1" BP, DuPont, Associated British Foods, and HYPERLINK "http://biopact.com/2006/10/interview-with-sir-richard-branson-on.html" Virgin), is on Biobutanol as the alternative energy source of the future.

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