Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
DETAILED ACTION
The instant application is a U.S. National Phase of PCT/EP2019/079433 filed on 10/28/2019, with foreign priority application DE10 2018 126 953.6, filed October 29, 2018. Applicant’s amendment filed May 16, 2025 is acknowledged. Claims 11 and 15 are canceled, and claim 1 is amended. Currently claims 1-10 and 12-14 are pending, and claim 14 is withdrawn.
The previous 102(a)(1)(a)(2) rejection in the Final office action mailed December 23, 2024 is withdrawn due to Applicant’s amendment to the claims filed May 16, 2025.
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on May 16, 2025 has been entered.
Claim Objections
Claim 1 is objected to because of the following informalities: lines 10-11, “controlling and regulating the pH value continuously to be kept at a pH value at a given value of below or at pH 10 by adding…” needs to be changed to “controlling and regulating the pH value continuously to keep the pH equal to or less than 10, by adding…” for convoluted language. Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1-10 and 12-13 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Claim 1 as amended recites “(ii) the CO2 containing gas comprises H2S at an amount of at least 200 ppm;”, and appears to depart from the claims as originally filed and the specification does not support an amount of H2S of at least 200 ppm with no upper limit. The Specification only describes the CO2 containing gas may comprise H2S in an amount between 0 and 50,000 ppm (pg. 25, lines 1-2). Therefore considered new matter. See MPEP 2163.05.
If Applicant believes that such support is present in the specification and claimed priority documents, Applicant should point, with particularity, to where such support is to be found.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-10 and 12-13 are rejected under 35 U.S.C. 103 as being unpatentable over Krajete (WO 2012110256 A1, cited in PTO-892 mailed 3/5/2024, hereinafter “Krajete”) in view of Yan et al. (Bioresource Technology 259 (2018) 67–74, hereinafter “Yan”), as evidenced by Awe et al. (Waste Biomass Valor (2017) 8:267–283, cited in PTO-892 mailed 7/3/2024, hereinafter “Awe”) and DSMZ-German Collection of Microorganisms (Media 119, 2022, pgs. 1-2, cited in PTO-892 filed 3/5/2024).
Regarding claims 1, 5 and 12, Krajete teaches a method of converting carbon dioxide and hydrogen to methane by methanogenic microorganisms (abstract). The method consists of contacting the methanogenic microorganisms with in-gas comprising carbon dioxide and hydrogen sulfide in a reaction vessel (abstract, pg. 30, line 14). The method includes a continuous mode of cultivation, where the methanogenic bacteria are continuously supplied with fresh medium and other gases, such as hydrogen and carbon dioxide (pg. 45, lines 24-28). Further, the in-flow of gases for cell growth were set to a partial pressure ratio of carbon dioxide to hydrogen to be maintained from a range of 1:0.5 to 1:5 (parts carbon dioxide: parts hydrogen), well within the instant range 1:0.6-1:5 CO2:H2 which anticipates claim 1 (pg. 58, line 22). Krajete teaches both gases are generally fed into the reaction vessel of the invention according to the desired ratio of their partial pressures and may be pure or contaminated with other gases tolerated by the system (pg. 41, lines 6-10). Krajete teaches the carbon dioxide used in the method may be pure or high quality/purity “ideal gas” or “real gas” that it comprises beside CO2, also other gases which are denoted as contaminants, but preferably, the carbon dioxide comprising real gas is purified according to any of the techniques known in the art, to increase the carbon dioxide content to around 80%, which inherently meets the limitation of at least 20% CO2 in the CO2 containing gas (pg. 31, lines 26-30).
Krajete teaches the oxidation reduction potential is adjusted or maintained using a reducing agent by adjusting the hydrogen or oxygen in-gas feed into the reaction vessel (pg. 8, lines 1-3). Krajete further teaches the in-gas may have certain amounts of oxygen, and it is preferred to have a very low oxygen contamination inside reaction vessel, preferably below 2% which meets this limitation in claim 1 (pg. 44, lines 28-30). The methane produced inside the reactor is typically between 50-80% methane and may be collected and further used for energy applications which meets this limitation in claim 1 (pg. 30, lines 1-7).
The pH value inside the reactor is maintained from 5.0-8.0, by adding acid or base to control pH, well below the pH in instant claims 1 and 5 (pg. 8, line 6; pg. 49, lines 13-14). Inside the reaction vessel, the pressure may be adjusted to a value in the range from 1 bar to 500 bar absolute which significantly overlaps within the range recited in claim 12 (pg. 45, lines 1-2).
Krajete does not explicitly disclose the CO2 containing gas comprises H2S at an amount of at least 200 ppm as recited in claim 1. However Krajete does teach ‘real gas’ may be used as the in-gas, which means that the gas is not absolutely pure, i.e. is gas mixture, which denotes beside carbon dioxide and hydrogen comprises other gases such as hydrogen sulfide (pg. 15, para 1). A typical example for a real gas is "biogas" or also the off-gas of the method of the invention, "biogas" typically refers to a gas produced by the biological breakdown of organic matter, and can be from sources such as sewage, municipal waste, inter alia (pg. 15, para 1). As evidenced by Awe, a typical biogas composition comprises 0-4000 ppm hydrogen sulfide, which overlaps with the range of at least 200 ppm hydrogen sulfide recited in claim 1 (pg. 268, Table 1). Awe also discloses biogas comprises 30-40% CO2 and 0% oxygen, which also inherently meets these limitations in claim 1 (pg. 268, Table 1).
Although Krajete is silent on the effects of pH regulation in relation to hydrogen sulfide, Yan teaches hydrogen sulfide control and microbial competition in batch anaerobic digestion and the effect of initial sludge pH (title). Yan teaches high sulfur content in excess sludge impacts the production of biomethane during anaerobic digestion, mean-while leads to hydrogen sulfide (H2S) formation in biogas (abstract). Yan teaches when the initial sludge pH increased from 6.5 to 8.0, the biogas production increased by 10.1%, the methane production increased by 64.1%, while the H2S content in biogas decreased by 44.7% (abstract). Yan teaches the higher initial sludge pH inhibited the competition of sulfate-reducing bacteria with methane-producing bacteria, and thus benefitted the growth of methanogens (abstract).
Therefore it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date to utilize the method of producing methane from real gas that comprises at least 20% CO2, 0-4000ppm H2S, and less than 2% oxygen contamination, while culturing methanogens with additional H2 in a stoichiometric ratio of 1:0.6 to 1.5, controlling and regulating the pH by adding a suitable acid or base, and collecting said methane as taught by Krajete, and modify the Krajete’s method by increasing the initial pH up to 8.0 to remove and reduce H2S in the resulting methane gas as taught by Yan with a reasonable expectation of success. One of ordinary skill in the art would have been motivated to increase the pH of the continuous methanogenic culture to reduce competition between sulfate-reducing bacteria and methane-producing bacteria, benefitting methanogenic growth, while simultaneously reducing H2S production as taught by Yan.
Regarding claim 3, Krajete teaches that in response to oxygen contamination of the reaction vessel, the oxidation reduction potential has to be stabilized using sulfide, such as sodium sulfide, or else, adjusting the hydrogen in-gas feed and the pH value (pg. 41, lines 27-29; pg. 8, line 2).
Regarding claim 4, Krajete teaches methanogenic microorganisms as having a biomass concentration of at least 6 g biomass per liter, wherein no additional methanogenic microorganism is added after inoculation or cell retention is applied during fermentation, which is well within the instant range (abstract). Biomass was determined as dry weight using standard drying procedures and gravimetric determination of pre-weighted glass tubes and optical density was measured using a spectrophotometer (Hitachi U-1100, Japan) at an absorption of 578 nm (pg. 55, lines 12-15).
Regarding claims 6, 7, and 9, Krajete teaches the fermentation conditions are principally the same for all methanogenic microorganisms, but in particular the species: Methanosarcinia barkeri, Methanothermobacter marburgensis, Methanobacterium thermoautotrophicus, Methanocaldococcus jannaschii, Methanothermobacter thermoautotrophicus, Methanococcus maripaludis, or mixtures thereof (pg. 60-61, sec. 7.). The methanogenic strains were anaerobically transferred into the bioreactor and maintained under anaerobic conditions (pg. 54, sec. 3.). The strains used in Krajete’s invention were obtained from a variety of environmental sources, such as anaerobic soils and sands, inter alia (pg. 25, lines 13-20). One particular strain Krajete uses is Methanothermobacter marburgensis DSM 2133 (pg. 61, sec. 7). As evidenced by DSMZ, DSM 2133 is grown on DSMZ medium 119, which consists of NaCl and NH4Cl at concentrations of 0.4 g/L, respectively, which falls within the range of the instant’s definition of a moderately saline environment of instant claim 9 (DSMZ, spec: pg. 23, lines 7-9).
Regarding claim 10, Krajete teaches an objective of the invention is the fixation of carbon dioxide which is released through industrial and agricultural processes and from industrial plants, i.e., waste carbon dioxide (pg. 3, lines 11-13). Krajete teaches the carbon dioxide gas can be ‘real gas’, wherein real gas sources delivering real gas, such as natural sources, industrial processes (industrial "waste gas") (pg. 32, lines 12-15).
Regarding claim 13, Krajete teaches the ‘off-gas’ or ‘output gas’ that is the gaseous outcome of the reaction vessel may comprise water vapor, the gases comprised in the in-gas, and methane (pg. 29, lines 21-23). During methane production
phase, the off-gas mixture mainly comprises methane, most preferably the methane content is at least 92%, 94% or 96% wherein the higher the content the more preferred (pg. 30, line 1).
Regarding claims 2 and 8, Krajete teaches the medium used to culture the bacteria provide nitrogen and salts and the bioreactor system is made anaerobic by flushing with 80%/20% (v/v) H2/CO2 for five minutes (pg. 54, lines 15-21). The reaction vessel also includes a stirrer that is adjusted for optimal high gas liquid mass transfer (pg. 44, lines 4-5). In general, the reaction volume, i.e., the culture volume, inside the reaction vessel is kept constant, so that also gaseous and/or liquid substances have to be removed from the reaction vessel depending on the total mass in-flow (pg. 45, lines 27-30). The bioreactor comprises a device for removing a liquid substance or a cell suspension from the reaction vessel (pg. 48, lines 19-20). The temperature inside the reaction vessel depends on the methanogenic microorganism which is used for the method of the invention, but in general should be in the range from 40°C to 100°C (pg. 43, lines 21-23). Krajete also teaches a standard medium for culture has the following composition: 2.1 g NH4Cl; 6.8 g KH2PO4; 3.4 g Na2CO3; 0.09 g Titriplex I; 0.04 g MgCl2 x 6H2O; 0.01 g FeCl x 4H2O; 0.2 mg CoCl2 x 6H2O; 1.2 mg NiCl2 x 6H2O; 0.2 mg NaMoO4 x 2H2O, which includes the chloride anion amounts in the range 12-300mmol/L of instant claim 8 (pg. 27, lines 23-25).
Krajete does not teach the specific range of temperature inside the bioreactor as being 32-90°C, nor the specific chloride anion range of the liquid culture medium as being 12-300mmol/L. Krajete teaches the bioreactor’s temperature to be between 40-100°C and the specific chloride anion concentration can be calculated based on the components of the medium culture composition. However, in the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art is a prima facie case of obviousness (See In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990), MPEP 2144.05).
Response to Arguments
Applicant’s arguments, see pgs. 5-6, filed May 16, 2025, with respect to the rejection(s) of claim(s) 1, 3-7, 9-10, and 12-13 under 102(a)(1)(a)(2) and claims 2 and 8 under 103 have been fully considered and are persuasive. Therefore, the rejections have been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Krajete and Yan.
Applicant argues Krajete does not recognize the problem that occurs with the presence of H2S in the CO2 containing gas, nor does Krajete teach or suggest a solution to be found from controlling and regulating the pH continuously. Applicant argues there is an unexpected benefit for controlling and regulating the pH continuously as claimed, wherein the culture could be stabilized in high levels of H2S contamination when the pH is actively regulated below pH 10.
The Examiner agrees Krajete is silent on the specific amounts of H2S in the in-gas but does specifically teach ‘real gas’ or ‘biogas’ may be used which does overlap with the H2S limitation recited in claim 1. Krajete does not specifically address these limitations in relation to H2S contamination and regulating pH below 10, although Krajete does teach pH probes measure the bioreactor, and acid or base is added by titration to control pH as desired. Further Krajete does teach the limitation of keeping the pH value below 10, and kept at a constant of 6.8 using 1M (NH4)2CO3 as base in order to compensate for acidification of the medium during growth of M. marburgensis (pg. 26, para 1). Yan teaches increased H2S may be produced in the biogas, causing many problems, such as inhibition of anaerobic digestion process, decrease of biogas production and methane content, and that by regulating and controlling the pH, methane production was increased and H2S contamination was decreased in the resulting biogas (pg. 68, col. 1, para 2; pg. 73, sec. 4.). Thus, the newly added Yan reference teaches a motivation to control and regulate the pH below 10, in relation to high levels of hydrogen sulfide contamination. Therefore, it would have been prima facie obvious to one of ordinary skill in the art to modify the method taught by Krajete, with the teachings of pH regulation in relation to H2S control taught by Yan with a reasonable expectation of success. The unexpected results the Applicant argues of regulating the pH below 10 in the presence of high H2S contamination in the claimed process would be expected based on the teachings of Yan. Furthermore, the ‘unexpected results’ in the specification are not commensurate in scope of the newly amended claims, since the instant claims do not include an upper limit in the amount of H2S in the CO2 containing gas.
Conclusion
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/JESSICA EDWARDS/
Examiner
Art Unit 1657
/ABIGAIL VANHORN/Primary Examiner, Art Unit 1636