The Fed Circuit affirmed denial of a preliminary injunction in a patent infringement suit brought by Butamax Advanced Biofuels against Gevo, Inc. (Butamax Advanced Biofuels LLC v. Gevo, Inc., No. 2012-1490, Nov. 16, 2012). The Butamax patent covered a fermentation process for producing butanol by a transgenic yeast engineered to express five exogenous enzymes that form a biosynthetic pathway for converting an inexpensive carbon-source feedstock to butanol at elevated levels.

The district court denied a preliminary injunction on the grounds that the plaintiff had failed to show likelihood of success on either the infringement or validity issues. The Fed Circuit was unsympathetic to the lower court’s analysis on claim construction and infringement, but agreed that the plaintiff’s case for patent validity was shaky. The grounds for challenging the validity of the Butamax patent are captured in the rejection of claim 1 made in a then-pending reexamination proceeding. The main points from this rejection are:

“Claim 1 is drawn to a method of producing biobutanol by a recombinant yeast microorganism in fermentation medium. There is no specific limitation given on the amount of isobutanol produced by the yeast. The claim describes a biosynthetic pathway that is inherently present in yeast strains to produce isobutanol from pyruvate through a series of enzymatic reaction, pathway steps a, b, c, d and e” (of the claimed method).”

“Claim 1 only requires that the recombinant yeast is ‘expressing an engineered isobutanol biosynthetic pathway.’ There is not specific description of where and how this pathway is engineered.”

“There is no requirement in the claim for any specific genetic alteration or introduction of specific nucleic acid sequences.”

The lessons to be drawn from this rejection are pretty basic: (1) If the claimed reaction pathway is carried out by a native microorganism, though at a low level, the specification should support and the claims should reflect the elevated levels of product achieved by the engineered organism; (2) the specification should provide specific directions as to the type and extent of genetic engineering needed to  achieve the claimed result; and (3) where the native microorganism contains the genes involved the claimed pathways, the claim should specify novel sequences and/or control elements that produce elevated levels of product.