Vinasse: Study aims to turn ethanol waste into feed

University of Hawaii researchers are studying whether they can turn a byproduct of ethanol into feed for fish or cattle.

Hawaiian Commercial and Sugar Co. says the results could determine whether the company produces ethanol in the islands.

Lee Jakeway, the company's director of energy development, said HC&S is supporting the research because the technology "would be helpful in upgrading what is considered a waste product into something that would be value-added as animal feed."

The company doesn't currently have a good solution for what to do with vinasse, the waste byproduct of ethanol fermentation.

"That's been holding us back from moving forward with ethanol production," Jakeway said.

Samir Khanal, a UH-Manoa molecular biosciences and bioengineering professor leading the research, was co-investigator of an Iowa State University project that won a 2008 research prize from the American Academy of Environmental Engineers.

The Iowa researchers grew a fungus in fermentation leftovers from corn-produced ethanol. They said it saved energy, recycled more water and improved livestock feed.

Khanal's project has potential for both aquaculture and agriculture, Jakeway said.

"Cattlemen are interested in alternative feeds. On Maui, we use our cane trash already for animal feed supplements and a supplement for molasses," he said.

Clyde Tamaru, UH Sea Grant agriculture extension specialist and co-investigator on the project, said Khanal's research is "very far-reaching."

Alternative protein sources must be developed to replace imported fishmeal, he said.

"A good example is we have two open-ocean farms for moi and kahala, which require high protein diets," he noted.

"Right now, it is still efficient because the cost of fishmeal as a protein source is one of the most inexpensive sources of protein," Tamaru added. "Eventually that is going to change."

Using vinasse for animal feed may also help relieve already overburdened landfills by eliminating the need to dump the byproduct.

Furthermore, Khanal says with transportation costs rising, there is "a pressing need" to develop a locally available low-cost substitute for imported fishmeal and other imported protein.

Khanal's UH co-investigators include Harry Ako and Jon-Paul Bingham in the Molecular Biosciences and Bioengineering Department. Also on board is James Carpenter in the Food and Animal Sciences Department. At the Oceanic Institute, Warren Dominy of Aquatic Feeds and Nutrition Department director is joining the research.