Microbe Discovery Could Create More Fuel
A newly created microbe produces cellulose that can be turned into ethanol and other biofuels, report scientists from The University of Texas at Austin. The microbe could provide a significant portion of the nation's transportation fuel if production can be scaled up.
Along with cellulose, the cyanobacteria developed by Professor R. Malcolm Brown Jr. and David Nobles Jr., Ph.D., secrete glucose and sucrose. These simple sugars are the major sources used to produce ethanol.
"The cyanobacterium is potentially a very inexpensive source for sugars to use for ethanol and designer fuels," says Nobles, a research associate in the Section of Microbiology and Molecular Genetics.
Brown and Nobles say their cyanobacteria can be grown in production facilities on non-agricultural lands using salty water unsuitable for human consumption or crops.
Other key findings include:
• The new cyanobacteria use sunlight as an energy source to produce and excrete sugars and cellulose
• Glucose, cellulose, and sucrose can be continually harvested without harming or destroying the cyanobacteria (harvesting cellulose and sugars from true algae or crops, like corn and sugarcane, requires killing the organisms and using enzymes and mechanical methods to extract the sugars)
• Cyanobacteria that can fix atmospheric nitrogen can be grown without petroleum-based fertilizer input
Nobles made the new cyanobacteria (also known as blue-green algae) by giving them a set of cellulose-making genes from a non-photosynthetic "vinegar" bacterium, Acetobacter xylinum, well known as a prolific cellulose producer.
The new cyanobacteria produce a relatively pure, gel-like form of cellulose that can be broken down easily into glucose.
Brown sees a major benefit in using cyanobacteria to produce ethanol is a reduction in the amount of arable land turned over to fuel production and decreased pressure on forests.
"The pressure is on all these corn farmers to produce corn for non-food sources," says Brown, the Johnson & Johnson Centennial Chair in Plant Cell Biology. "That same demand, for sucrose, is now being put on Brazil to open up more of the Amazon rainforest to produce more sugarcane for our growing energy needs. We don't want to do that. You'll never get the forests back."
Brown and Nobles caution that there is a lot of work ahead before cyanobacteria can provide fuel in the field. Work with laboratory-scale photobioreactors has shown the potential for a 17-fold increase in productivity.
They recently published their research in the journal Cellulose.