I’ve been covering the ongoing patent litigation between advanced biofuels company Gevo and BP-DuPont joint venture Butamax over a number of patents relating to methods of producing biobutanol.
The lawsuit started in January 2011 with Butamax’s initial complaint filed in federal court in Delaware alleging infringement of U.S. Patent No. 7,851,188 (’188 Patent), later amended to include U.S. Patent No. 7,993,889 (’889 Patent). Gevo counterclaimed, accusing Butamax of infringing U.S. Patent Nos. 8,017,375 (’375 Patent and 8,017,376 (’376 Patent).
Earlier this year, the court handed Gevo a partial victory when it granted the company’s motion for summary judgment of no infringement of the ’188 and ’889 Patents under the doctrine of equivalents.
Now Butamax has notched a win in a recent decision granting its motion for summary judgment of non-infringement of the ’375 and ’376 Patents.
The patents are directed to methods of producing isobutanol using a recombinant microorganism, achieving theoretical yields of greater than about 10%. The claims of the ’375 Patent recite a 5-step chemical pathway, and the fourth step in the pathway is conversion of alpha-ketoisovalerate to isobutyraldehyde.
The problem for Gevo was that it had initially filed a broad claim covering the use of any enzyme to convert alpha-ketoisovalerate to isobutyraldehyde and later amended the claim to specifically recite an “alpha-ketoisovalerate decarboxylase from Lactococcus lactis.” Butamax’s process uses a Lactococcus grayi enzyme from a different source and having a very different amino acid sequence than the Lactococcus lactis enzyme claimed by Gevo.
The court noted that, with the amendment, Gevo had argued that its L. lactis enzyme showed unexpected results to overcome a prior art rejection during prosecution of the application that matured as the ’375 Patent. Therefore, to prove that the Butamax process infringes the ’375 Patent under the doctrine of equivalents, Gevo needed to demonstrate that “the L. grayi enzyme or any other enzyme also yielded the unexpected results that it relied on to overcome the prior art.”
The court held that Gevo could not prevail on infringement under the doctrine of equivalents and granted Butamax’s motion for summary judgment:
To allow Gevo to allege that the enzymes are equivalent “would vitiate [the] claim limitation” requiring an “alpha-ketoisovalerate decarboxylase from Lactococcus lactis.”….Therefore, Gevo cannot assert infringement of independent claim 1 through the application of the doctrine of equivalents for enzymes other than what it specifically claimed, i.e., an “alpha-ketoisovalerate decarboxylase from Lactococcus lactis.”….Gevo does not argue that Butamax’s use of the L. grayi enzyme literally infringes independent claim 1 of the ’375 patent. For the foregoing reasons, the court grants Butamax’s motion for summary judgment of non-infringement of the asserted claims 1-3 and 5-7 of the ’375 patent.
The claim element at issue in the ’376 Patent was the recombinant overexpression of the gene coding the Aft protein, causing an increase of Aft protein in the cell. The function of the claim is to increase the enzymatic activity of the enzyme DHAD. This is achieved through recombinant yeast cells engineered to provide increased expression of Aft1 and/or Aft2.
However, in Butamax’s strain, there is a deletion of an FRA2 gene, which does not directly produce excess Aft protein, but instead removes the negative regulator, allowing native Aft protein to be used in a greater amount. Gevo argued that deleting the FRA2 gene is equivalent to overexpressing the Aft gene.
The court disagreed because the claim language of the ’376 Patent requires overexpression of the Aft protein:
In the case at bar, to find that Butamax’s strains are the equivalent of Gevo’s strains would render the limitation of overexpressing Aft superfluous and would essentially negate the manner in which the limitation achieves transcription of the genes in the iron regulation.
The court further held there could be no infringement under the doctrine of equivalents because of the different functions and operations of the FRA2 deletion and the Aft overexpression:
The deletion of FRA2 does not perform the same function in substantially the same way as the overexpression of Aft1, as it does not increase the Aft protein levels as called for by the claim, in order to then increase the enzymatic activity of DHAD. Instead the deletion of FRA allows native Aft1 protein to be used in the iron regulation. As the claim language (and indeed the parties’ agreed upon construction) requires the increase of Aft1 via overexpression, the court concludes that the doctrine of equivalents does not apply.
So Butamax went two for two on non-infringement, succeeding on summary judgment for both the ’375 and ’376 Patents.
Butamax also achieved a partial victory on invalidity, as the court granted its motion for summary judgment that the ’375 Patent is invalid for lack of enablement and written description. The patent claims high yields of glucose of greater than 50% up to greater than 97.5% while the examples in the written description show a highest obtained yield of only 12.8%.
Thus, the court held the ’375 Patent invalid for lack of written description support for the claims:
As to written description, the court concludes that Butamax has shown, by clear and convincing evidence, that persons skilled in the art would not recognize a description of the higher yields of the claimed invention.
And on enablement:
The court concludes that Gevo has only offered conclusory allegations to support yields above the reported 12.8% and, therefore, has not offered any evidence to show that the full scope of claim 1 was enabled. There is no expert testimony that would allow a reasonable jury to conclude that the higher yields would be achievable at all, or at least without undue experimentation.
On validity of the ’376 Patent, the only success for Gevo in this decision, the court found the parties raised genuine issues of fact as to whether the patent has adequate written description and the claims are enabled and therefore denied Butamax’s summary judgment motion.
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