Posted On: March 22, 2013 by James L. Higgins

Judge Robinson rules on summary judgment motions involving patented biological method of producing isobutanol.

Judge Sue L. Robinson recently issued a memorandum opinion granting summary judgment of invalidity for lack of written description and no infringement under the doctrine of equivalents of a patented method of producing isobutanol using genetically-engineered yeast microorganisms aimed at reducing greenhouse gas emissions. Butamax™ Advanced Biofuels LLC v. Gevo, Inc., Civ. No. 11-54-SLR (D. Del. Mar. 19, 2013). Before addressing the merits of several competing summary judgment motions, the Court construed the disputed claims as follows:

“acetohydroxy acid isomeroreductase” was construed to mean “an enzyme known by the EC number 1.1.1.86 that catalyzes the conversion of acetolactate to 2,3-dihydroxyisovalerate and is NADPH-dependent”

“a recombinant yeast microorganism expressing an engineered isobutanol biosynthetic pathway” was construed to mean “a recombinant yeast microorganism that is genetically transformed such that it expresses the five enzymes that form the biosynthetic pathway described hereafter for the production of isobutanol, wherein one or more of those enzymes is recombinantly expressed”

“(pathway step a;…(pathway step b);…,” etc. was construed to mean “the pathway of steps a-e are contiguous steps such that the product of step a is the substrate for step b; the product of step b is the substrate for step c; etc.”

“The microorganism produces isobutanol as a single product” was construed to mean “[t]he microorganism produces isobutanol without substantial amounts of other fermentation products”

Id. at 8-23.

The Court considered, in light of these claim constructions, the parties competing motions for summary judgment on the question of infringement. The Court first explained that the plaintiff’s “evidence of infringement is less than compelling, nonetheless, . . . it [is] sufficient to withstand [the defendant’s] motion for summary judgment, as it raises genuine issues of material fact as to how a person of ordinary skill in the art at the time the invention was made would determine NADH-dependency.” Id. at 39. The Court granted, however, the defendant’s motion for summary judgment of no infringement under the doctrine of equivalents, which asserted that the defendant’s “NADH-dependent enzyme is not equivalent to an NADPH-dependent enzyme.” Id. at 39-40. In light of its claim construction, the Court disagreed with the plaintiff’s position that “the use of NADH as an electron donor is insubstantially different from the use of NADPH.” Id. at 40 (quoting D.I. 648 at 33).

The Court then considered several competing motions for summary judgment on the question of validity. The defendant argued that claim 12 (“[t]he recombinant yeast microorganism of claim 1 wherein the said microorganism further comprises inactivated genes thereby reducing yield loss from competing pathways for carbon flow”) and claim 13 (“[t]he recombinant yeast microorganism of claim 12, wherein said inactivated genes reduce pyruvate decarboxylase activity”) were invalid for lack of written description. Id. at 50-51. With regard to claim 12, the Court found that the patent “mentions inactivation of genes only once” and that “[n]one of the cited portions of the specification provide a description to one of skill in the art on how to construct a recombinant yeast microorganism with ‘inactivated genes’ to reduce ‘yield loss from competing pathways.’” Id. at 51, 52. “Although the specification may be interpreted as identifying both the . . . problem and the solution, it does not even begin to describe how to put into practice the solution.” Id. at 52. Similarly, the specification nowhere disclosed “inactivated genes” that “reduce pyruvate decarboxylase activity[,]” and the Court found that claim 13 was also invalid for lack of written description.

Butamax™ Advanced Biofuels LLC v. Gevo, Inc., Civ. No. 11-54-SLR (D. Del. Mar. 19, 2013).