A federal judge has barred expanded sales of a new corn-based biofuel made in Minnesota as two companies battle in court over patent rights on the processing technology.

Gevo Inc., which just finished converting a Luverne, Minn., ethanol plant into the world's first commercial-scale corn-derived isobutanol production facility, said the ruling issued Tuesday won't affect its existing sales contracts, including one with the U.S. Air Force for experimental jet fuel.

"We see it as very positive, a victory for us," said Brett Lund, Gevo executive vice president and general counsel. "The other side wanted to shut down everything. The judge said no.''

The other company is Butamax Advanced Biofuels, a joint venture of BP and DuPont. Gevo, based in Englewood, Colo., and Butamax, of Wilmington, Del., have separately developed technology to ferment isobutanol using bioengineered yeasts, and the companies are suing each other for patent infringement in U.S. District Court in Delaware. Two trials are set for 2013.

Both companies believe isobutanol has major advantages over ethanol. When mixed with gasoline, isobutanol has more energy than ethanol. And unlike ethanol, it can be pumped through pipelines. Isobutanol also is being tested as a military jet fuel, and can be used to make plastics, paint and other products.

In a temporary restraining order, U.S. District Judge Sue L. Robinson limited shipments of isobutanol from the Luverne plant to Sasol, an international energy and chemical company, and the Air Force for fuel testing. The order remains in effect while the judge considers Butamax's request for an injunction against Gevo.

Each company has three lawsuits pending against the other, with five cases filed this year. Butamax, which filed the first case last year, has argued in court that it was "compelled to sue" because Gevo infringed on patents in "a mad rush to beat Butamax to the market."

Gevo has denied that charge, and accused Butamax not only of infringing on its yeast technology patents, but on its plant-conversion technology. Gevo also has challenged Butamax's claims with the U.S. Patent Office.

Lund said Sasol and the Air Force have contracted to purchase all of the plant's capacity, so the order won't leave Gevo with unsold isobutanol, he said. "It maintains the status quo," Lund said.

In a statement, Butamax CEO Paul Beckwith said he was pleased with the ruling, saying it offers "protection for markets of key interest to Butamax."

Gevo shares closed up 10 cents, or 1.8 percent, at $5.75.

David Shaffer • 612-673-7090