Patentability Case-Study: Tracing Hotchkiss, A.&P., and Lyon (RCTA)

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(Homework 2)

Cited Patents

  • Patent 2,389,263
  • Method of Producing 2:3 Butanol
  • Patented Nov. 20, 1945
  • Alfred J. Liebmann and George de Becze
    • Assignors to Schenley Distillers Corporation, NY

  • Patent 1,875,536
  • Continuous Butyl Alcohol Fermentation Process
  • Patented Sept. 6, 1932
  • Maynard C. Wheeler and Charles D. Goodale
    • Assignors to Commercial Solvents Corporation, IN


Sidney Levy’s 1984 patent cites the 1932 patent of M. C. Wheeler et al, “Continuous Butyl Alcohol Fermentation Process,” and the 1945 patent of A. J. Liebmann et al, “Method of Producing 2:3-Butanediol.” For the purposes of this analysis, I will assume that the Wheeler patent would not have interfered with the Liebmann patent given the analyses of Hotchkiss and A.&P., even if this is not the case. All three patents claim processes for fermentation and extraction of a desired substance from a fermentation brew. In the Liebmann et al patent, the aim is to produce a “substantially pure 2:3 butylene glycol (Col. 1, lines 2-3) while greatly reducing “the cost of extraction of the butylene glycol from a fermented beer which contains said glycol” (Col. 1, lines 13-16). The claims in the Wheeler et al patent are much closer to the claims of Levy’s patent. Like Levy, Wheeler et al disclose a “continuous process for the fermentation of carbohydrate-containing mashes by means of butyl alcohol producing bacteria” (lines 1-4). They also treat the production of n-butyl alcohol and other common products through micro-organisms such as Clostridium acetobutylicum; this is also similar to the Levy patent. Furthremore, both Wheeler et al and Levy hope to address common shortcomings in old batch-reactor acetobutylicum processes while also claiming under a patent a continuous process for the production of solvents by fermentation of carbohydrate substrates. Liebmann et al claim a fermentation and extraction, but their patent pertains to a different product with very different properties and is produced by an organism that behaves differently. Furthermore, the Liebmann et al patent claims both batch and continuous processes where Levy and Wheeler et al’s patents both pertain to continuous processes exclusively. All three patents claim both a process that allows for the continuous production of solvents and their extraction as well as an apparatus for conducting this process. Both Wheeler et al and Levy allow for the continuous production of n-butanol using various substrates and extraction solvents while achieving higher n-butanol concentrations and using various extraction solvents.

For the criterion of nonobviousness, it is important to note the following aspects of each patent. All patents give general descriptions of which fermentation agents and solvents can be employed in the process at each stage, but they also relate specific constraints and examples of each class. The Levy patent describes a continuous process that involves one tubular reactor, consisting of concentric tubes, and an extraction column. Condensers and feed tanks are employed as needed. One of the concentric tubes of the reactor contains a matrix that serves to immobilize the fermenting bacteria. Liebmann et al disclose a method for fermentation and concentration of a butylene-glycol-containing beer, followed by the recovery, extraction, and precipitation of the butylene-glycol. The process can be conducted continuously, as semi-batch, or batch. The process primarily involves separating the beer into a solvent phase and a semi-sludge phase. Each is then treated with solvents. The emphasis is upon the extraction portion of the process and not the fermentation. Several examples of both batch and continuous processes are given.

The device disclosed by Wheeler et al is closer to Levy’s invention. Both start with a coarse carbohydrate meal that is diluted to 8% in water. It is pressure cooked in steam and then cooled to 37°C. The mash is then inoculated with the fermenting culture at 2% by volume. New mash is added at intervals. The device differs primarily in its lack of a culture matrix and in the use of a series of tanks rather than a large plug-flow tank.

Analysis of Hotchkiss v. Greenwood, 52 U.S. 11

Hotchkiss required “invention” for patentability, and despite a dissenting opinion, the Court held that the patent in question was invalid because it lacked this inventiveness. As per the case syllabus, “The test was that if no more ingenuity and skill was necessary to construct the new knob than was possessed by an ordinary mechanic acquainted with the business, the patent was void.” The invention had to possess a “degree of skill and ingenuity” beyond that of the “ordinary mechanic acquainted with the business.” In the Hotchkiss case, the Court held that the clay or porcelain knob in question was not patentable because “the knob of clay was simply the substitution of one material for another,” and that the other parts and their mode of connection were in common use before. In other words, the patent tried to claim as novel what was a “mere substitution” of material.

Levy’s invention may not have been patentable under the analysis in Hotchkiss, despite the significant technical hurdles present in creating a reliable, efficient, and economically viable continuous fermentation process for n-butanol. One could argue that Levy merely substituted a pre-existing mesh for the continuous adding of bacteria. Indeed, Levy’s invention also relies on an initial inoculum, just as both of referenced patents so require. The devices used in the fermentation are also more similar than the drawings suggest. Wheeler et al use a cascade of fermentation tanks, but while only three are illustrated, the patent recognizes the possible use of many. The cascade becomes a plug-flow reactor in Levy, but plug-flows are analyzed, for practical purposes, as a cascade with many tanks in series. Furthermore, other pieces of the Levy process are nearly identical to those in the Wheeler et al process. Both require two “cooks” (or carbohydrate charges) to enter the first tank that are cooled, with subsequent charges added later. Both also have similar extraction requirements, with the addition that several extraction towers may be used. All of these stages serve the same function in each process.

The most important part of the Hotchkiss ruling lies in the "inventiveness" requirement. While something could be "better" and "cheaper," it had to go beyond "mere substitution." A trivial improvement could not be an invention. It also illustrates that having a patent does not guarantee property rights.

Analysis of A. & P. Tea Co. v. Supermarket Corp., 340 U.S. 147

Some of the same considerations would have also barred the patentability of Levy’s invention given the standard set by the A.&P. Court. Under A.&P., the patent on a cashier’s counter equipped with a three-sided rack for making grocery store check-out more efficient was held invalid. The Court cited Lincoln Engineering Co. of Illinois v. Stewart-Warner Corp.: “The mere aggregation of a number of old parts or elements which, in the aggregation perform or produce no new or different function or operation than that theretofore performed or produced by them, is not patentable invention.” Furthermore, the Court noted, “The conjunction or concert of known elements must contribute something; only when the whole in some way exceeds the sum of its parts is the accumulation of old devices patentable.” The rationale provided for this test goes back to the primary function of patents: to encourage addition to open knowledge. Therefore, a “patent for a combination which only unites old elements with no change in their respective functions, such as is presented here, obviously withdraws what already is known into the field of its monopoly and diminishes the resources available to skillful men” and cannot be allowed to stand as valid.

When the Wheeler et al and Leibmann et al patents are taken together, the Levy process as a whole seems like a combination of parts from the first two patents. The extraction phases of Leibmann et al and Levy are similar. The fermentation phases of Wheeler et al and Levy also are very similar, as previously discussed. Furthermore, all of the individual parts of Levy’s invention do not serve any new function. The condensers, extractors, pipes, fermentation tank, and matrices do the same things that they do in other contexts. There is no change to their “respective functions.” A.&P. would not allow Levy’s patent to stay valid because it withdraws elements that were already known to the chemical engineering field. While it is an improvement upon Wheeler et al and Liebmann et al, the stringent A.&P. standard would bar its patentability.

Analysis of modern nonobviousness and closing remarks

In enacting §103 of the U.S. Code, Congress sought to reform the patentability criterion of “inventiveness” that had stood, however confusingly, from the days of Lincoln and A. &. P.. The Lyon Court recognized that many elements of the process that Lyon used were similar to processes that were used, published, and commonly known in the field before he made his invention. However, most of them “so widely diverged from that of Lyon that under §100(b) they would not serve as anticipations.” Furthermore, even the closest to an “anticipation” did not take the crucial step that Lyon took—the second step that allowed him to create a coating that many people, including the United States Navy, recognized as a pressing need.

Similarly, while many of the process steps and devices used in the Levy patent might have been used before, he was able to integrate them in such a way as to satisfy a long-standing need in the field which had never before been adequately addressed. The production and extraction of n-butanol from carbohydrate substrate was not accomplished to an acceptably profitable state. Several aspects of Levy’s invention were important in this respect. The addition of the culture matrix and the recycle methods into his extraction reduced costs significantly. The modern processes of fermentation and extraction of n-butanol all rely on a culture matrix that hearkens back to Levy. Modern processes look strikingly similar to Levy’s device; the arrangements of Wheeler et al and Liebmann et al might have worked in principle and on bench-scale, but industry-scale processes cannot realistically use either one. The arrangement that Levy began is currently being deployed by several companies in pilot-scale plants. The culture matrix, the recycle loop, and the achievement of adjustable flows in the extraction tower were all nonobvious under the requirements of 35 USC 103 as shown under Lyon.

The standards of inventiveness or nonobviousness changed significantly between Hotchkiss and A.&P. and Lyon. Certain factors that would have served to bar patentability in the past were eased. With regard to Hotchkiss, cases must be examined closely before “mere substitution” might be used as grounds to bar patentability. The sharp distinction between “aggregation” and “invention” arose at the time of A.&P., but its restriction has also relaxed, as shown in the discussion pertaining to the Lyon standard. At the time of A.&P., patents were viewed as being reserved for very elevated purposes; they had to contribute substantially to scientific advancement. Despite the confusion around the standard for invention, everything was absorbed into nonobviousness with the enactment of 35 USC 103. In short, the Lyon Court examined the context of the patent closely, and so the Lyon standard is better at recognizing when significant advances to a particular field are accomplished. From this perspective, the dissenting opinion in Hotchkiss is closer to the modern standard than what the Court held at the time. Seeing the value in an invention that was similar to something that came before except that it was "better" and "cheaper" ties into today's standard of, among other considerations, meeting a long-felt need in a field.