STILLWATER, Okla. (AP) - An Oklahoma State University professor says she's found a way to turn byproducts from the production of soda pop into ethanol.
Biosystems and agricultural engineering associate professor Danielle Bellmer said that by adjusting the pH levels she has found that the leftover materials from soda manufacturing can be converted into ethanol. The pH is a measure of acidity.
"As a waste source, right now as it is in the waste stream, it's got zero value, so turning that into fuel is much more valuable," she said.
Bellmer began looking into the idea of converting the waste into ethanol after Tulsa-based Lamco Recycling contacted her in fall 2009 to find an alternative method of disposal. The local Pepsi Bottling Group contracts Lamco to dispose of the byproducts from production. Lamco disposes of waste by adjusting the pH level and sending it to a local wastewater treatment plant, a method that can be costly because it can be done only in limited quantities.
Bellmer and four OSU biosystems and agricultural engineering students tested different types of soda to see how easy it was to ferment soda waste into ethanol.
Turns out it was fairly easy. By adding a nitrogen source and Superstart, a common dry yeast, Bellmer and the students discovered it took anywhere from three to 10 days, depending on the amount of yeast added and the temperature, for the soda's sugar to ferment into ethanol. About 6 to 7 percent alcohol is converted from the 12 to 13 percent sugar found in one two-liter soda bottle, Bellmer said.
Jonathan Lim, a junior biosystems engineer, said the presence of sodium benzoate, a common food preservative, was the major indicator in whether a particular brand of soda would ferment well or not. Lim worked on the project last summer and set up and conducted many of the experiments.
"If we can pretty much take all this soda that is going to be thrown away anyway and turn it into at least a useful supplement to our fuel sources, I think that could be something to look forward to in the future," he said.
An analysis has not been done to see if converting the waste on a large scale is economically viable, Bellmer said.