DETAILED ACTION
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 .
Status of Claims
Claims 1-12 are currently pending and under consideration.
Priority
Acknowledgment is made of applicant’s claim for foreign priority and papers submitted under 35 U.S.C. 119 (a)-(d). The present application claims the benefit of the earliest effective filing date to Application No. KR10-2024-0058464 and all claims are being examined with an effective filing date of 05/02/2024. Please note that the Korean application is in a foreign language and therefore cannot be reviewed. In future actions, the effective filing date may change due to amendments or further review of priority documents.
Claim Rejections - 35 USC § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-12 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 is indefinite due to the recitation of “periodically supplying oxygen” because the scope of “periodically” is unclear. The claim does not specify a frequency, interval, or other objective criterion by which the periodic oxygen supply is determined. Although the Specification discloses exemplary oxygen supply cycles, including a supply cycle of 7 to 12 hours and supply based on the degree of oxygen consumption in the reactor (para 0037), the Specification expressly states that the supply cycle is not limited thereto and does not otherwise provide an objective boundary for determining what frequency or interval constitutes “periodically” supplying oxygen. Accordingly, one of ordinary skill in the art would not be reasonably apprised of the scope of the claimed periodic oxygen supply. For examination purposes, under the broadest reasonable interpretation, “periodically supplying oxygen” is interpreted to encompass any amount of elapsed time between successive supplies of oxygen. Dependent claims 2-12 are included in this rejection because they inherit the above-described indefiniteness.
Claim 9 is indefinite due to the recitation of “PHB (polyhydroxyvalerate)” because it is unclear whether applicant intends to claim the recited “PHB”, i.e., polyhydroxybutyrate, or claim the recited polyhydroxyvalerate, i.e., “PHV”. The instant Specification similarly identifies PHB as polyhydroxyvalerate (para 0047) and therefore does not resolve the ambiguity. For the purposes of examination, the examiner will interpret “PHB (polyhydroxyvalerate” as encompassing 2 separate products, both PHB (polyhydroxybutyrate) and PHV (polyhydroxyvalerate).
Claim 10 recites “resupplying the medium, separated from the product, back into the reaction unit”; however, there is insufficient antecedent basis for “the medium.” It is unclear what material previously recited in the claims constitutes “the medium” that is separated from the product and resupplied to the reaction unit. For purposes of examination, in view of the absence of any further limitation as to the identity or composition of the medium, “the medium” is broadly construed as encompassing a material or feed used to support cultivation and/or metabolism of the aerobic methanotroph in the reaction unit.
Appropriate response and clarification of all of the above is required.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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 1-11 are rejected under 35 U.S.C. 103 as being unpatentable over Criddle et al. (US Patent No. 9062340B2, cited in PTO-892) and Stegantseva et al. (WO2021071966A1, cited in PTO-892).
Regarding claims 1, 6 and 9, Criddle et al. teaches a method comprising cultivating methanotrophic cells in a bioreactor supplied with methane. Specifically, Criddle et al. teaches enriching a microbial feedstock comprising Type I and Type II methanotrophic cells in a bioreactor with a methane source and a nitrogen source and exposing the Type II methanotrophs to an unbalanced growth condition whereby production of polyhydroxybutyrate (PHB) is induced (Specification, para 0009). Criddle et al. further teaches that methane and oxygen may be provided continuously to the Type II methanotrophic cells (para 0013), thereby teaching cultivation of aerobic methanotrophs in the presence of methane and oxygen. Additionally, Criddle et al. teaches a sequencing batch bioreactor for PHB production from methane comprising a vessel, mixer, nutrient inlet, PHB and waste outlet, oxygen inlet, and methane inlet, and selecting reactor configurations and operating conditions that enable high levels of PHA production with minimal energy inputs (para 0070-0071). Specifically, Criddle et al. teaches that methane or oxygen may be reduced or eliminated in the bioreactor during exposure to nitrogen sources (para 0015) and further teaches that methane oxidation is mediated by methane monooxygenase, which requires methane, oxygen, and electrons, and that the rate of methane oxidation may be limited by the availability of methane or oxygen (para 0096). Moreover, Criddle et al. teaches operating the methanotrophic culture under cyclic conditions in which the availability of methane and nutrients is varied between different periods of the cultivation cycle (para 0059 and 0062-0063). Thus, Criddle et al. teaches that oxygen is a required reactant for methane conversion whose supply may be controlled, including by reducing or eliminating oxygen during portions of reactor operation, and further teaches varying reactor conditions between different periods of a cultivation cycle. However, Criddle et al. does not expressly teach periodically supplying oxygen or separating a final gas containing carbon dioxide from the product generated by the aerobic methanotroph.
Stegantseva et al. teaches culturing methanotrophic bacteria for the generation of biomass, and further teaches embodiments wherein methane is the carbon source, air or pure oxygen for oxygenation and ammonia as a nitrogen source (pg. 7). Furthermore, Stegantseva et al. teaches continuous methane fermentation in which fermentation broth containing the microbial biomass is pumped from the fermentation vessel and collected, and teaches that gas analysis of methane, oxygen, and carbon dioxide is performed during biomass collection, thereby demonstrating the presence of a carbon-dioxide-containing gaseous phase separate from the recovered microbial product (Example 1, pg. 19).
An invention would have been obvious to a person of ordinary skill in the art, if some teaching in the prior art would have led that person to combine the prior art reference teachings to arrive at the claimed invention. Before the effective filing date of the claimed invention, the teachings of Criddle et al., that oxygen is required for methane oxidation and may be reduced or eliminated during portions of reactor operation, together with the teaching of operating the methanotrophic culture under cyclic conditions in which reactor conditions are varied between different periods of the cultivation cycle, would have led a person of ordinary skill in the art to periodically supply oxygen to the reaction unit of Criddle et al., such that oxygen is supplied to support methane oxidation during appropriate periods of the cultivation cycle and reduced or eliminated during other periods, such as during exposure to nitrogen sources. Such operation would coordinate oxygen delivery with the differing metabolic conditions of the cultivation cycle while remaining consistent with Criddle et al.’s stated objective of achieving high levels of PHA production with minimal energy inputs. Furthermore, the teachings of Stegantseva et al. that, during continuous methane fermentation, fermentation broth containing the microbial biomass is collected separately while a gaseous phase containing methane, oxygen, and carbon dioxide is present during biomass collection would have led a person of ordinary skill in the art to separate the carbon-dioxide-containing gaseous phase from the microbial product generated in the process of Criddle et al. Such separation would permit recovery and subsequent processing of the desired microbial product separately from the gaseous fermentation phase, as successfully demonstrated by Stegantseva et al. during biomass collection. There is a reasonable expectation of success because Criddle et al. demonstrates successful cultivation of methanotrophs under controlled and cyclic methane, oxygen, and nutrient conditions for the production of PHB, while Stegantseva et al. demonstrates successful continuous methane fermentation wherein microbial biomass is collected separately in the presence of a carbon-dioxide-containing gaseous phase. Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention.
Regarding claim 2, Criddle et al. teaches that the type II methanotroph can be a Methylosinus spp. or Methylocapsa spp., or Methylocystis spp. for the production of PHB (para 0101).
Regarding claims 3-4, Criddle et al. teaches cultivation conditions comprising 5% oxygen and 95% methane (para 0035), thereby providing methane at a concentration within the claimed range, and an oxygen partial pressure of approximately 5.3% (PO2/PCH4=5/95=0.0526) of the methane partial pressure, which is also within the claimed range.
Regarding claim 5, Criddle et al. teaches that methane oxidation by methane monooxygenase requires oxygen and that the rate of methane oxidation may be limited by oxygen availability (para 0096). Although Criddle et al. does not expressly teach supplying oxygen when all oxygen in the reaction unit has been consumed, before the effective filing date of the claimed invention, the teachings of Criddle et al. regarding the requirement for oxygen in methane oxidation would have led a person of ordinary skill in the art to supply additional oxygen upon depletion of oxygen in the reaction unit in order to prevent oxygen availability from limiting methane oxidation and permit continued methane conversion. There is a reasonable expectation of success because Criddle et al. demonstrates successful methane conversion by methanotrophic cells supplied with methane and oxygen. Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention.
Regarding claim 7, Criddle et al. teaches that the concentration of nitrogen sources may be varied to promote growth of methanotrophs or inhibit growth of Type I methanotrophs, and further teaches periodic nitrogen concentration reductions and concentration returns during cultivation (para 0017-0018). Criddle et al. also teaches that nitrogen concentration is quantitatively related to cell growth, explaining that nitrogen constitutes about 12% of dry cell weight and that a corresponding amount of nitrogen must be supplied in relation to the amount of cell dry weight produced (para. 0044). Furthermore, Criddle et al. evaluates multiple nitrogen concentrations to determine their effects on methanotroph growth and PHB production (paras. 0104–0105). Thus, Criddle et al. teaches that nitrogen-source concentration relative to the amount of methanotrophic culture is a variable affecting methanotroph growth and product formation. Criddle et al. does not expressly teach continuously supplying the nitrogen source at a concentration of 1 to 10 g/L per 1 g/L of the aerobic methanotroph.
Stegantseva et al. teaches continuous cultivation of methanotrophic bacteria wherein a defined culture medium, or components thereof, is continuously added to the culture system, and further teaches maintaining a limited nutrient, including nitrogen, at a fixed rate while allowing other parameters to vary (pg. 6-7).
An invention would have been obvious to a person of ordinary skill in the art if some teaching in the prior art would have led that person to combine the prior art reference teachings to arrive at the claimed invention. Before the effective filing date of the claimed invention, the teachings of Criddle et al. that nitrogen-source concentration is varied to control methanotroph growth and PHB production, together with the teachings of Stegantseva et al. that nitrogen may be supplied continuously at a fixed rate during continuous methanotroph cultivation, would have led a person of ordinary skill in the art to continuously supply the nitrogen source in the method of Criddle et al. while adjusting the nitrogen-source concentration relative to the concentration of methanotrophs in order to maintain desired growth and product-formation conditions. Because Criddle et al. expressly identifies nitrogen concentration as affecting methanotroph growth and PHB production and evaluates multiple nitrogen concentrations for that purpose, determination of an operable or optimum nitrogen-source concentration, including the claimed range of 1 to 10 g/L per 1 g/L of aerobic methanotroph, would have involved routine optimization of a recognized result-effective variable. Pursuant to MPEP 2144.05, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). There is a reasonable expectation of success because Criddle et al. demonstrates successful control of methanotroph growth and PHB production through variation of nitrogen-source concentration, while Stegantseva et al. demonstrates successful continuous methanotroph cultivation using continuous addition of culture-medium components and maintenance of nutrients such as nitrogen at a fixed rate. Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention.
Regarding claim 8, Criddle et al. teaches the method described above wherein the nitrogen source comprises urea (para. 0012 and Table 1).
Regarding claim 10, Stegantseva et al. teaches continuous methanotroph cultivation wherein used culture medium is removed from the culture unit for processing and further teaches continuously removing fermentation broth and separating the microbial biomass therefrom by centrifugation and Criddle et al. teaches recycling material associated with PHB production, wherein an alkaline waste stream resulting from recovery of PHA granules is subjected to anaerobic digestion to methane, which is collected and recycled as feedstock for continued methanotroph cultivation (para 0051). Before the effective filing date of the claimed invention, the teachings of Stegantseva et al. regarding removal of fermentation medium and separation of microbial biomass therefrom, together with the teachings of Criddle et al. that methane-containing feedstock associated with PHB production may be recovered and recycled for continued cultivation, would have led a person of ordinary skill in the art to resupply usable medium remaining after separation of the desired microbial product back into the reaction unit in order to reuse available cultivation feedstock and reduce the need for additional feed material. There is a reasonable expectation of success because Criddle et al. expressly demonstrates the feasibility of recycling recovered methane as feedstock for methanotroph cultivation. Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention.
Regarding claim 11, as described above, Criddle et al. teaches cultivating methanotrophs using methane as a carbon substrate for the production of PHB and further teaches that methane is oxidized by methane monooxygenase and that the rate of methane oxidation may be limited by methane availability. Before the effective filing date of the claimed invention, the teachings of Criddle et al. that methane is utilized as a carbon substrate by the methanotrophs during cultivation for the production of PHB would have led a person of ordinary skill in the art to continue cultivation until the available methane substrate in the reaction unit is consumed in order to utilize the available carbon substrate for methane conversion and product production rather than terminate cultivation while usable substrate remains. There is a reasonable expectation of success because Criddle et al. demonstrates successful cultivation of methanotrophs using methane as the carbon substrate for methane conversion and PHB production. Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention.
Claim 12 is rejected under 35 U.S.C. 103 as being unpatentable over Criddle et al. and Stegantseva et al. as applied to claim 1 above, and further in view of Bussmann et al. (Cultivation of methanotrophic bacteria in opposing gradients of methane and oxygen, FEMS Microbiol Ecol 56 (2006) 331–344, cited in PTO-892) and Mayr et al. (Lake mixing regime selects apparent methane oxidation kinetics of the methanotroph assemblage, Biogeosciences, 17, 4247–4259, 2020, cited in PTO-892).
The teachings of Criddle et al. and Stegantseva et al., as they apply to claim 1, have already been discussed above and being relied upon. Briefly, Criddle et al. and Stegantseva et al. make obvious a method comprising culturing an aerobic methanotroph in the presence of methane and oxygen-containing gas to generate a product and separating a final gas from the generated product. Stegantseva et al. teaches that oxygen supplied to a methanotrophic culture may be provided as pure oxygen rather than as air. Therefore, it would have been obvious to one of ordinary skill in the art at the time of the invention to modify the method of Criddle et al. to employ pure oxygen as the oxygen-containing gas, as taught by Stegantseva et al., as a known alternative oxygen source for aerobic methanotrophic cultivation and avoids introduction of nitrogen associated with an air feed. However, neither Criddle et al. nor Stegantseva et al. expressly teach wherein the final gas consists of carbon dioxide and water.
Bussmann et al. further teaches cultivation of methane-oxidizing bacteria in opposing gradients of methane and oxygen, wherein methane-oxidizing bacteria require methane as an electron donor and oxygen as a coreactant and electron acceptor (pg. 331). Bussmann et al. experimentally determined the distribution of methane and oxygen in the resulting cultures and reports that oxygen penetrated only to the depth of the methanotrophic growth band, methane was not detectable above the growth bands, and the growth bands were consistently observed at locations where the concentrations of both oxygen and methane approached zero (pg. 335 and Fig. 1). Thus, Bussmann et al. demonstrates that aerobic methanotrophic cultivation may be carried out under conditions in which the methane and oxygen substrates are consumed to concentrations approaching zero.
Mayr et al. teaches that aerobic methane oxidation by methane-oxidizing bacteria consumes methane and oxygen and expressly provides the stoichiometry of microbial methane oxidation as:
CH₄ + (2 − y)O₂ → (1 − y)CO₂ + yCH₂O_BM + (2 − y)H₂O
where y represents carbon-use efficiency and CH₂O_BM represents methanotrophic biomass (pg. 4252). Thus, Mayr et al. expressly establishes that carbon dioxide and water are gaseous products of aerobic microbial methane oxidation, with a portion of the methane carbon incorporated into biomass.
An invention would have been obvious to a person of ordinary skill in the art, if some teaching in the prior art would have led that person to combine the prior art reference teachings to arrive at the claimed invention. Before the effective filing date of the claimed invention, the teachings of Stegantseva et al. that either air or pure oxygen may be used for oxygenation of methanotrophic bacteria would have led a person of ordinary skill in the art to employ pure oxygen as the oxygen source in the methane-conversion process of Criddle et al., thereby supplying the oxygen required for aerobic methane oxidation while avoiding introduction of nitrogen associated with the use of air. Furthermore, the teachings of Bussmann et al. that aerobic methanotrophic cultivation can be operated under conditions wherein methane and oxygen are consumed to concentrations approaching zero would have led a person of ordinary skill in the art to operate the modified process under conditions sufficient to consume the supplied methane and oxygen, thereby minimizing residual methane and oxygen in the resulting gaseous phase. In view of Mayr et al.’s teaching that microbial methane oxidation consumes methane and oxygen and produces carbon dioxide and water, a person of ordinary skill in the art would have reasonably expected that operating the process using pure oxygen and consuming the methane and oxygen substrates would result in a final gas consisting of carbon dioxide and water, separate from the desired product. There is a reasonable expectation of success because Stegantseva et al. demonstrates the use of pure oxygen for methanotrophic cultivation, Bussmann et al. demonstrates successful methanotrophic cultivation under conditions wherein methane and oxygen approach depletion, and Mayr et al. establishes the stoichiometry of microbial methane oxidation whereby methane and oxygen are consumed, and carbon dioxide and water are produced. Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention.
Conclusion
No claim is in condition for allowance.
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/NAGHMEH NINA MOAZZAMI/Examiner, Art Unit 1652
/ROBERT B MONDESI/Supervisory Patent Examiner, Art Unit 1652
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