GM bacteria churn out 'microdiesel' fuel -

Genetically modified bacteria can produce a biodiesel from plant materials, researchers have shown. The GM bugs could help cut carbon dioxide emissions while also reducing the need to grow crops to make greener fuels, they say.
Biodiesel, also known as biologically-derived diesel substitute, can be made from rapeseed (canola), soy and oil palm, by heating it with a chemical catalyst.
This type of fuel can help offset greenhouse gas emissions because it is made from organisms that naturally remove CO2 from the atmosphere. However, large areas of land are still needed to cultivate raw materials, and toxic chemicals are also used to process them. The machinery used to harvest the materials also consumes fuel and oil themselves.
"Biodiesel is a good alternative energy source and a substitute for petroleum-based diesel fuel," says Alexander Steinbüchel, who created the new form of biodiesel with colleagues at the University of Munster in Germany. "But the current method of production is still costly."
Genetic codes
Steinbüchel's team created a fuel-refining strain of the common bacteria Escherichia coli by modifying it with genes taken from two other bacteria species. The modified E. coli were cultured in a mixture of glucose and the main constituent of olive oil, which it processed into a fatty acid diesel-substitute dubbed "microdiesel".
The German team used two genes from the bacterium Zymomonas mobilis to give E. coli the ability to produce alcohol from the sugar. A third gene, taken from the bacterium Acinetobacter baylyi, enabled the E. coli to then combine this alcohol with plant oils to produce microdiesel.
Unlike regular biofuel, microdiesel is produced without toxic chemicals. Steinbüchel says future work could allow microdiesel to be made using plant waste instead of plant oils. As plant waste is regularly generated through food production this would reduce the need to grow crops specifically for biodiesel.
Food or fuel?
"Due to the much lower price of those raw materials, as well as their great abundance, the microdiesel could result in a more widespread production of biofuel at a competitive price in the future", Steinbüchel says.
Microdiesel could also help alleviate demands on land, says Trevor Price, an environmental expert at Glamorgan University in Wales. "Biodiesel is seen by some as the answer to our problems with carbon dioxide and fossil fuels, but its does need a lot of land," he told New Scientist. "Borneo's rainforest is being destroyed for palm oil plantations and other countries may have to choose between food and fuel."
However, Price says simply stepping up biodiesel production will not address environmental pollution. "Instead of trying to satisfy our demands for fuel by greener means we should first be trying to reduce them through better efficiency and other measures," he says.
Journal Reference: Microbiology (vol 152, p 2529)