After a court battle lasting more than three years, DuPont has come out on top in an appeals court case. The U.S. District Court for the Western District of Wisconsin has affirmed a May 2012 decision by Judge Barbara Crabb, who ruled the Novozymes patent on an alpha-amylase enzyme used in the ethanol industry is invalid for lack of an adequate written description.

"We are gratified the Court of Appeals affirmed the Wisconsin court’s ruling that the Novozymes patent is invalid,” said Soonhee Jang, vice president, intellectual property (IP) strategy and chief IP counsel, DuPont Industrial Biosciences, in a prepared statement. “From the outset of this case, we have firmly believed Novozymes’ patent to be invalid.”

Novozymes responded with a statement of its own. “We are disappointed that the court has ruled in favor of Dupont,” said Novozymes General Counsel Mikkel Viltoft. “We will now evaluate the decision and our options. Novozymes will continue to protect and defend its intellectual property rights.”

Novozymes originally filed the lawsuit in May 2010 against Danisco and the company’s enzymes division, Genencor International, businesses acquired by DuPont in 2011. A jury ruled in October 2011 that Novozymes patent was infringed on and the company was awarded damages of $18.2 million. However, a judge reversed that ruling in May 2012.

The case was appealed, resulting in a July 22 affirmation of the district court judgment. In a 32-page court opinion, the court concluded that the patent failed to satisfy the written description requirement and was invalid.