MUST It Be There? An Update on the Inherency Doctrine

By: Ko Nakamura


Anticipation under 35 U.S.C. §102 requires each limitation of a claim to be disclosed by a single prior art reference.  Such a disclosure may be explicit or inherent in the prior art.[1]  For a limitation to be inherently disclosed in the prior art, the limitation, while not explicitly disclosed, must necessarily be present in view of the explicit disclosure of the prior art.[2]

In U.S. Water Servs., Inc. v. Novozymes A/S, 2016 U.S. App. LEXIS 22244 (Fed. Circ. Dec. 15, 2016), U.S. Water Services and Roy Johnson (“U.S. Water”) brought a patent infringement action against Novozymes A/S and Novozymes North America, Inc. (“Novozymes”) in the U.S. District Court for the Western District of Wisconsin.

U.S. Water’s patents, U.S. Patent Nos. 8,415,137 and 8,609,399, relate to a method for reducing insoluble byproducts that deposit on processing equipment during ethanol production by adding phytase at different points of the ethanol production process.  The asserted claims recite both the addition of phytase and a resulting reduction of insoluble byproduct.[3]

The District Court granted Novozymes’s summary judgment motion in part, holding the asserted claims invalid as being inherently anticipated by either International Publication No. WO 01/62947 A1 (“Veit”) or U.S. Patent No. 5,756,714 (“Antrim”) under 35 U.S.C. §102(b).  Veit discloses adding phytase during saccharification and fermentation stages of ethanol production to increase fermentation and ethanol yields, and Antrim discloses adding a phytate degrading enzyme that includes phytase to the starch granules or starch solution prior to liquefaction.  The District Court held that, while Veit and Antrim do not explicitly disclose the reduction of insoluble byproduct recited in the claims, “the prior art discloses the conditions that will necessarily result in phytase reducing deposits.”

When deciding whether to grant a summary judgment motion, “[the court] must view the evidence and draw all inferences in a way most favorable to the nonmoving party.” Bombard v. Fort Wayne Newspapers, Inc., 92 F.3d 560 (7th Cir. 1996) (citation omitted).  The Federal Circuit reversed the District Court’s grant of summary judgment with respect to inherency, noting that there was a genuine dispute as to a material fact regarding whether the addition of phytase disclosed by Veit and Antrim necessarily results in the insoluble byproduct reduction of the claims.  The Federal Circuit noted that there was conflicting evidence, including expert testimony, regarding whether the addition of phytase as disclosed by Veit and Antrim would always result in insoluble byproduct reduction.  For example, one of U.S. Water’s experts testified that “one can employ phytase enzyme according to Antrim…and Veit in ways that could sufficiently affect the phytic acid and phytates present to improve liquefaction and fermentation, but which would be insufficient to have any effect on the formation of deposits.”  The Federal Circuit further noted that disregarding this conflicting evidence required credibility determinations and weighing of the evidence, which was improper.  Therefore, the Federal Circuit held that the District Court’s grant of summary judgment was erroneous,[4] and reversed the District Court’s grant of summary judgment motion with respect to inherency.

This case illustrates the difficulty in proving inherency, because while the party challenging the patent must show that the allegedly inherent subject matter is necessarily included in the prior art, the patent holder merely has to show a single instance where the prior art does not include the allegedly inherent subject matter.  In this particular case, to survive the summary judgment motion, U.S. Water merely had to show that, in each prior art reference, there was a possibility of the reduction in the insoluble byproduct not resulting from the addition of phytase.  The case also underscores the importance of expert testimony during litigation, which was the sole evidence that U.S. Water relied on to survive the summary judgment motion.

From the patent prosecutor’s perspective, this case is a helpful restatement of the law, underscoring the strict standard that must be met to show inherency.  Citation to this case will be helpful in situations where an examiner asserts a claimed element is “inherent” in prior art without making the necessary showing that the element must (as opposed to could) be present.


[1] “A claim is anticipated only if each and every element as set forth in the claim is found, either expressly or inherently described, in a single prior art reference.” Verdegaal Bros. v. Union Oil Co. of California, 814 F.2d 628, 631, 2 USPQ2d 1051, 1053 (Fed. Cir. 1987).

[2] “To serve as an anticipation when the reference is silent about the asserted inherent characteristic, such gap in the reference may be filled with recourse to extrinsic evidence. Such evidence must make clear that the missing descriptive matter is necessarily present in the thing described in the reference, and that it would be so recognized by persons of ordinary skill.” Continental Can Co. USA v. Monsanto Co., 948 F.2d 1264, 1268, 20 USPQ2d 1746, 1749-50 (Fed. Cir. 1991).

[3] For example, claim 1 of U.S. Patent No. 8,415,137 recites “adding phytase to an ethanol processing fluid in the equipment containing phytic acid or salts of phytic acid under conditions suitable for converting the insoluble phytic acid or phytic acid salts to soluble products; thereby reducing the formation of deposits of insoluble phytic acid or phytic acid salts on surfaces in the equipment,” and claim 1 of U.S. Patent No. 8,609,399 recites “wherein providing the additive comprising phytase in the ethanol processing fluid causes a reduction of the formation of insoluble deposits of phytic acid and/or salts of phytic acid in a piece of heat transfer equipment in the plant.”

[4] “The District Court erred in deeming irrelevant the fact that ‘U.S. Water . . . adduced evidence[, including expert testimony,] . . . that practicing Veit and Antrim will not always result in deposit reduction.’” U.S. Water Servs., Inc. v. Novozymes A/S, at 8.