HANOVER, N.H. (AP) _ Researchers at Dartmouth College and an affiliated company say they have taken a significant step in the quest to make ethanol from wood, grass and other cellulosic plant material.

The researchers genetically altered a bacterium so less of it is needed to make ethanol.

They published their work online last week in a scientific journal.

Unlike the oil used to make gasoline, the plants used to make ethanol are a renewable resource. But ethanol in the United States comes from corn, and ethanol production has undercut the world food supply and driven up the price of corn.

Dartmouth Professor Lee Lynd calls the research a first step.