Direct Cellulose - Isobutanol Conversion Achieved

What has been engineered is a celluloseprocessing bacteria able to produce isobutenol in one step.  This is good news and perhaps opens the doorto a prospective farm based protocol in which cellulose is ground up anddigested to specifically produce fuel grade isobutanol.

We certainly wish to avoidhauling plant waste anywhere.  A waste tofuel system is badly needed for agriculture, no matter what else develops.  Farm energy is best served with burnablebiofuels for the foreseeable future if we can solve the conversion challenge.

Two problems are solved.  The waste is easily consumed and process fuelis made available right where it is needed. This fuel has the added advantage of overcoming the disadvantages ofethanol.  

Researchers use bacteria to produce potential gasoline replacementdirectly from cellulose

By DarrenQuick

00:23 March 10, 2011

http://www.gizmag.com/isobutanol-biofuel-cellulose-bacteria/18106/

With the situation in Libyacausing a spike in fuel prices worldwide there's some good biofuel-relatednews out of the U.S.Department of Energy's BioEnergy Science Center(BESC) that could help to reduce many countries' dependence on oil imports. Forthe first time, BESC researchers have succeeded in producing isobutanoldirectly from cellulosic plant matter using bacteria. Being a higher grade ofalcohol than ethanol, isobutanol holds particular promise as a gasolinereplacement as it can be burned in regular car engines with a heat valuesimilar to gasoline.

Due in large part to its natural defenses to being chemicallydismantled, cellulosic biomass like corn stover and switchgrass, which isabundant and cheap, has been much more difficult to utilize than corn or sugarcane. This means that producing biofuel from such biomass involves severalsteps, which is more costly than a process that combines biomass utilization andthe fermentation of sugars to biofuel into a single process.

Building on earlier work at UCLA in creating a synthetic pathway for isobutanol production, the BESC researchersmanaged to achieve such a single-step process by developing a strain ofClostridium cellulolyticum, a native cellulose-degrading microbe that couldsynthesize isobutanol directly from cellulose.

"In nature, no microorganisms have been identified that possessall of the characteristics necessary for the ideal consolidated bioprocessingstrain, so we knew we had to genetically engineer a strain for thispurpose," said Yongchao Li of Oak Ridge National Laboratory.

The research team chose Clostridium cellulolyticum, which wasoriginally isolated from decayed grass, because it has been geneticallyengineered to improve ethanol production, which has led to additional moredetailed research. While some Clostridium species produce butanol and others digestcellulose, none produce isobutanol, an isomer of butanol.

"Unlike ethanol, isobutanol can be blended at any ratio withgasoline and should eliminate the need for dedicated infrastructure in tanks orvehicles," said James Liao, chancellor's professor and vice chair ofChemical and Biomolecular Engineering at the UCLA Henry Samueli School ofEngineering and Applied Science and leader of the research team. "Plus, itmay be possible to use isobutanol directly in current engines withoutmodification."

Earlier this week, U.S. Energy Secretary Steven Chu visited the BESC tocongratulate the research team, saying, "Today's announcement is yetanother sign of the rapid progress we are making in developing the nextgeneration of biofuels that can help reduce our oil dependence. This is aperfect example of the promising opportunity we have to create a major newindustry – one based on bio-material such as wheat and rice straw, corn stover,lumber wastes, and plants specifically developed for bio-fuel production thatrequire far less fertilizer and other energy inputs."

The team's work is published online in Applied and EnvironmentalMicrobiology.