Cornell University biological engineers have deciphered the cellular strategy to make the biofuel ethanol, using an anaerobic microbe feeding on carbon monoxide – a common industrial waste gas."Instead of having the waste go to waste, you make it into something you want," said Ludmilla Aristilde, assistant professor in biological and environmental engineering. "In order to make the microbes do our work, we had to figure out how they work, their metabolism."Aristilde collaborated with her colleague Lars Angenent, professor of biological and environmental engineering, on the project. She explained, "The Angenent group had taken a waste product and turned it into a useful product."To make biofuel from inorganic, gaseous industrial rubbish, the researchers learned that the bacterium Clostridium ljungdahlii responds thermodynamically – rather than genetically – in the process of tuning favorable enzymatic reactions.