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Producing ethanol from sweet sorghum

Dec. 14, 2012 - Delta BioRenewables, LLC, a sustainable feedstock producer and bioenergy project developer, has announced that its collaboration partner Commonwealth Agri-Energy, LLC has successfully produced ethanol from sweet sorghum sugars at its corn ethanol facility in Hopkinsville, Kentucky.

The industrial-scale evaluation, which utilized fermentable sugars from improved sweet sorghum hybrids developed by Ceres, Inc., marks the first step in demonstrating the commercial viability of integrating the new feedstock into existing domestic corn ethanol facilities. Sweet sorghum is on the pathway for acceptance as an advanced biofuel feedstock under the Renewable Fuel Standard, thus providing an additional financial incentive for corn ethanol facilities to adopt the crop.

Sweet sorghum is a drought-tolerant, low input crop, well adapted to most regions of the United States. It serves as a companion crop to corn and soybeans in an annual crop rotation system. According to Dr. Randall Powell, Delta BioRenewables' Chief Technology Officer, "These characteristics allow corn ethanol facilities to diversify their feedstock supply with a dedicated energy crop – one that could provide greater price stability, especially if grown under contract." Powell adds, "This successful trial proves the technical feasibility of integrating sweet sorghum sugars into existing corn ethanol facilities. It helps pave the way for other commercial projects."

To produce fuel from sweet sorghum, the stalks are harvested and crushed. The sugary juice is extracted, fermented and distilled. The co-product biomass is an excellent livestock feed, and can also be used for bioenergy applications. Delta BioRenewables has been developing the supply chain for sweet sorghum and other industrial sugar crops at its Memphis-area processing facility since 2009. For the evaluation, the company grew, harvested and processed Ceres' hybrids to a liquid sugar feedstock, which was then transported by commercial tanker to Commonwealth's 33-million-gallon-per-year corn ethanol facility, where it was directly introduced into the facility's fermentation system.

General Manager Mick Henderson said that Commonwealth Agri-Energy was pleased with the results and anticipates expanding the collaboration with Delta BioRenewables in 2013. "The sugars in sweet sorghum were fermented in the same way as corn, without any significant changes to our process. I believe that our co-op could produce 5% or more of our overall annual ethanol production using sweet sorghum grown on nearby marginal land and under-utilized pasture," said Henderson. "Everything came off without a hitch. We wanted to see the sweet sorghum juice in a full truckload lot, run our own analytical profile, and then introduce the juice in our fermentation system at full scale."

For the coming season, energy-crop company Ceres, Inc. is working with Delta BioRenewables and Commonwealth, which has 2,300 farmer members, to expand plantings of its improved sweet sorghum hybrids marketed under its Durasweet trade name. “Our Durasweet hybrids appear to be well adapted to Mid-South conditions, and have performed well on land where corn or soy yields may fall short,” said Frank Hardimon, Director of Sales at Ceres.

The project was funded, in part, by the United Sorghum Checkoff Program (USCP), a farmer-funded organization that invests in the research, marketing and outreach in order to expand markets for sorghum. “We see this significant commercial-scale trial as a catalyst for other corn ethanol facilities to consider diversification of their feedstock base,” said John Duff, Director of Renewables for USCP.

Early strategic planning support for the project was made possible through the partnership of Murray State University, West Kentucky AgBioworks, Memphis Bioworks Foundation, Kentucky Agriculture Development Fund, Kentucky Energy and Environment Cabinet, and USDA Rural Development.

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December 14, 2012  By Delta BioRenewables


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