Minn. ethanol plant to produce isobutanol

By Kris Bevill | July 15, 2010
Posted Aug. 10, 2010

Isobutanol technology developer Gevo Inc. has signed an agreement to purchase the 22 MMgy Agri-Energy LLC corn ethanol plant near Luverne, Minn. Gevo expects the sale to be finalized within the next two months and will then immediately begin retrofitting the plant to produce isobutanol.

Gevo has developed an integrated fermentation technology, dubbed GIFT, which uses a combination of synthetic biology and metabolic engineering to produce isobutanol from grain crops, sugarcane and sugar beets. According to the company, although isobutanol is a naturally occurring alcohol, high concentrations inhibit the growth of microorganisms. To combat this problem, Gevo has developed a technology that allows for the continuous separation of isobutanol as it is produced within ethanol plants. Gevo said the technology retrofit consists of a bolt-on separations unit that can be added while the plant is operating. It expects the Agri-Energy plant will need to shut down for only a few weeks at the end of the approximate two-year installation process. Gevo is not disclosing the cost of the retrofit or the terms of the acquisition agreement but said the price "is well within market norms for a profitable, well-run facility of this scale and vintage."

Agri-Energy founding member and co-op coordinator David Kolsrud said the move to produce isobutanol is in line with the company's devotion to advancing the technology and best practices of the ethanol industry. "We see biobutanol as the next logical step in the industry's development," he said. "We believe isobutanol can be sold into many markets and has product attributes that make it a compelling product for current ethanol producers."

Gevo said it has no plans to replace current Agri-Energy employees after it acquires the facility. "We were interested in this plant because it is well run," the company stated. "That is the result of the engineering design and the plant's excellent workforce. We do not want to change anything that has contributed to the plant's excellent performance profile." The plant's capacity will be reduced from 22 MMgy of ethanol to 18 MMgy of isobutanol, but the greater energy content of the isobutanol will make up for the 4 million gallon capacity reduction, according to Gevo. "We will use the same fermentation equipment and the same amount of corn input," the company stated. "But, the yield on the input is lower volumetrically because isobutanol is a higher carbon alcohol - four carbons instead of ethanol's two."

Isobutanol production is expected to begin by the first quarter of 2012. Gevo said the plant will be able to produce ethanol or isobutanol in batches, however it is likely that isobutanol will be the focus of production. "This transaction is another important step in achieving our goal of bringing commercial volumes of renewable isobutanol to the market as soon as possible," Gevo CEO Patrick Gruber said. "[Agri-Energy] is a great place to begin our commercialization effort. We expect the facility will be the first among many and want it to be a model project for the future."