April 9, 2008

 

US researchers develop GM corn for cheap ethanol

 

 

A team of US researchers recently developed a genetically modified corn that contains enzymes that can break down cellulose, the fibrous material found in the stalks and leaves of corn.

 

The development is considered a significant step towards developing cheap cellulosic ethanol.

 

Using genes taken from a microbe found in cow stomachs, Mariam Sticklen of Michigan State University and colleagues were able to grow corn that produces a key enzyme needed to break down cellulose.

 

Current efforts in the US to produce cellulose-digesting enzymes have inserted similar genes into common microbes such as E. coli and growing these enzymes in commercial bioreactors.

 

However, these reactors require huge amounts of energy for enzyme production.

 

Sticklen pointed that they have created a shortcut, as the GM corn is a green bioreactor using free energy from the sun.

 

Since 2005, the team has been growing the transgenic corn, known as Spartan Corn. The first version carried a single enzyme from a microbe found in hot springs and capable of breaking cellulose into large pieces.

 

The second version, Spartan Corn II, which was introduced in 2007, uses an additional gene found in fungus to produce an enzyme that takes these cellulose pieces and breaks them into pairs of sugar molecules.

 

The current study of Spartan Corn III employs both of these prior enzymes as well as a third, beta-glucosidase, from a microbe found in cow stomachs, to separate paired molecules into simple sugars.

 

These sugars can then be readily fermented to make ethanol.