Section 101 Examples
Example 14 (6): Bacterial Mixtures

This is an example provided by the U.S. Patent and Trademark Office for analyzing Section 101 patent subject matter eligibility issues. The example is one of the "Nature Based Product Examples" provided by the USPTO on December 16, 2014. The original PDF document is found here. The numbering of these examples is taken from Appendix 2 of the July 2015 Update on Subject Matter Eligibility.

This example should be viewed in light of the introduction that was provided with it.

Index to USPTO's Section 101 Examples
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Example 14 (6): Bacterial Mixtures

This example illustrates the application of the markedly different characteristics analysis to nature-based product claims produced by combining multiple components.


Rhizobium bacteria are naturally occurring bacteria that infect leguminous plants such as clover, alfalfa, beans and soy. Each species of bacteria will only infect certain types of plants, for example R. meliloti will only infect alfalfa and sweet clover, and R. phaseoli will only infect garden beans. It was assumed in the prior art that all Rhizobium species were mutually inhibitive, because prior art combinations of different bacterial species produced an inhibitory effect on each other when mixed together, with the result that their efficiency was reduced. Applicant has discovered that there are particular strains of each Rhizobium species that do not exert a mutually inhibitive effect on each other, and that these strains can be isolated and used in mixed cultures. Applicant has also discovered that certain Rhizobium species, when mixed together, exhibit biological properties that are different than in nature. For example, in nature or by itself, R. californiana will only infect lupine. When mixed with R. phaseoli, however, R. californiana will infect both lupine and wild indigo. R. californiana and R. phaseoli are not known to occur together in nature.


1. An inoculant for leguminous plants comprising a plurality of selected mutually non-inhibitive strains of different species of bacteria of the genus Rhizobium, said strains being unaffected by each other in respect to their ability to fix nitrogen in the leguminous plant for which they are specific.
2. An inoculant for leguminous plants comprising a mixture of Rhizobium californiana and Rhizobium phaseoli.

Analysis of Claims:

These claims are analyzed for eligibility in accordance with their broadest reasonable interpretation. Because both claims are directed to a statutory category, e.g., a composition of matter (Step 1: YES), and are nature-based products (a mixture of bacteria), the markedly different characteristics analysis is used to determine if the nature-based products are exceptions.

Claim 1: Ineligible.

There is no indication in the specification that the claimed mixture of bacteria has any characteristics (structural, functional, or otherwise) that are different from the naturally occurring bacteria. Thus, the mixture does not have markedly different characteristics from what occurs in nature, and is a “product of nature” exception. Accordingly, the claim is directed to an exception (Step 2A: YES). Because the claim does not include any additional features that could add significantly more to the exception (Step 2B: NO), the claim does not qualify as eligible subject matter, and should be rejected under 35 U.S.C. § 101.

The inoculant of claim 1 was held to be ineligible subject matter in Funk Brothers Seed Co. v. Kalo Inoculant Co., 333 U.S. 127, 131 (1948):

Discovery of the fact that certain strains of each species of these bacteria can be mixed without harmful effect to the properties of either is a discovery of their qualities of non- inhibition. It is no more than the discovery of some of the handiwork of nature and hence is not patentable. The aggregation of select strains of the several species into one product is an application of that newly-discovered natural principle. But however ingenious the discovery of that natural principle may have been, the application of it is hardly more than an advance in the packaging of the inoculants. Each of the species of root-nodule bacteria contained in the package infects the same group of leguminous plants which it always infected. No species acquires a different use. The combination of species produces no new bacteria, no change in the six species of bacteria, and no enlargement of the range of their utility. Each species has the same effect it always had. The bacteria perform in their natural way. Their use in combination does not improve in any way their natural functioning. They serve the ends nature originally provided and act quite independently of any effort of the patentee.
Recently, the Supreme Court looked back to this claim as an example of ineligible subject matter, stating that “the composition was not patent eligible because the patent holder did not alter the bacteria in any way.” Myriad, 133 S. Ct. at 2117.

Claim 2: Eligible.

In nature, R. phaseoli only infects garden beans, and R. californiana only infects lupine. When mixed together as claimed, the combination now infects a third species of plant: R. californiana infects both lupine and wild indigo, but R. phaseoli continues to only infect garden beans. The combination of species thus has changed R. californiana such that, when combined with R. phaseoli, it has a different characteristic (biological function) than it had in nature, i.e., the claimed combination infects a new group of leguminous plants (wild indigo) as compared to the naturally occurring bacteria by themselves. This functional difference rises to the level of a marked difference, and accordingly the claimed mixture is not a “product of nature” exception. Note that unless the examiner can show that this particular mixture of bacteria exists in nature, this mere possibility does not bar the eligibility of this claim. See, e.g., Myriad, 133 S. Ct. at 2119 n.8 (“The possibility that an unusual and rare phenomenon might randomly create a molecule similar to one created synthetically through human ingenuity does not render a composition of matter nonpatentable” (emphasis in original)). Thus, the claim is not directed to an exception (Step 2A: NO), and qualifies as eligible subject matter.