Prosecution Insights
Last updated: April 19, 2026
Application No. 18/628,548

METHODS FOR PRODUCING BIOGAS AND RENEWABLE NATURAL GAS USING CO-PRODUCTS FROM A STILLAGE STREAM AS FEEDSTOCKS

Non-Final OA §102§103
Filed
Apr 05, 2024
Examiner
HOLLAND, PAUL J
Art Unit
1656
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Marquis Ip LLC
OA Round
1 (Non-Final)
58%
Grant Probability
Moderate
1-2
OA Rounds
3y 1m
To Grant
99%
With Interview

Examiner Intelligence

Grants 58% of resolved cases
58%
Career Allow Rate
439 granted / 764 resolved
-2.5% vs TC avg
Strong +65% interview lift
Without
With
+65.3%
Interview Lift
resolved cases with interview
Typical timeline
3y 1m
Avg Prosecution
55 currently pending
Career history
819
Total Applications
across all art units

Statute-Specific Performance

§101
8.0%
-32.0% vs TC avg
§103
31.6%
-8.4% vs TC avg
§102
18.6%
-21.4% vs TC avg
§112
29.5%
-10.5% vs TC avg
Black line = Tech Center average estimate • Based on career data from 764 resolved cases

Office Action

§102 §103
DETAILED CORRESPONDENCE Application Status 1. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . 2. Claims 1-20 are pending. Priority 3. Acknowledgement is made of applicants’ claimed domestic priority to U.S. Provisional Application No. 63/457,778, filed on 04/06/2023. Drawings 4. The Drawings filed on 04/05/2024 are acknowledged and accepted by the examiner. Claim Rejections - 35 USC § 102 5. The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. 6. Claim(s) 1-2, 5, 7, 9-11, 13-14, 16, and 18-20 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Aurandt et al. (US Patent Application Publication 2017/0058300 A1; examiner cited). 7. Claims 1-2, 5, 7, 9-11, 13-14, 16, and 18-20 are drawn to a method for producing biogas, comprising: (a) introducing a feedstock comprising clarified thin stillage (CTS) or clarified thin stillage syrup (CTS syrup) to an anaerobic digester; and (b) digesting the anaerobic digester to produce biogas. 8. With respect to claim 1, Aurandt et al. teach a method for producing biogas, comprising: (a) introducing a feedstock comprising clarified thin stillage (CTS) or clarified thin stillage syrup (CTS syrup) to an anaerobic digester; and (b) digesting the anaerobic digester to produce biogas such as methane [see Abstract; Figures 3-5; paragraphs 0066-0075]. With respect to claim 2, Aurandt et al. teach the method wherein the feedstock comprising clarified thin stillage [see Abstract; Figures 3-5; paragraphs 0066-0075]. With respect to claim 3, Aurandt et al. teach the method wherein the feedstock comprises CTS syrup [see Abstract; Figures 3-5; paragraphs 0066-0075]. With respect to claim 7, Aurandt et al. teach the method wherein the CTS syrup comprises a total suspended solid at concentration of about 2,000 ppm or 1,000 ppm (which is less than about 15% wt) [see paragraph 0078]. With respect to claim 9, Aurandt et al. teach the method wherein the feedstock comprising clarified thin stillage and CTS syrup [see Abstract; Figures 3-5; paragraphs 0066-0075]. With respect to claim 10, Aurandt et al. teach the method wherein the feedstock further comprises process condensate [see paragraphs 0064, 0072]. With respect to claim 11, Aurandt et al. teach the method wherein the digesting is performed using a hydraulic retention time of less than 24 hours [see paragraph 0077]. With respect to claim 13, Aurandt et al. teach the method further comprising purifying the biogas to produce methane (renewable natural gas) [see paragraph 0083]. With respect to claim 14, Aurandt et al. teach the method wherein the purifying comprises separating CO2 from the biogas to produce a CO2 rich stream and a methane rich stream [see paragraph 0083]. With respect to claim 16, Aurandt et al. teach the method wherein the methane rich stream is further purified to produce renewable natural gas [see paragraph 0083]. With respect to claim 18, Aurandt et al. teach the method wherein the anaerobic digester is a stirred tank reactor [see paragraphs 0091-0096]. With respect to claim 19, Aurandt et al. teach the method wherein the digestion process comprising nitrogenous content, so absent evidence otherwise, it is the examiner’s position that the CTS or CTS syrup would necessarily have a native C:N ratio [see paragraphs 0016-0018]. With respect to claim 20, Aurandt et al. teach a method comprising removing residual biomass remaining the anaerobic digester and processing for use as fertilizer [see paragraphs 0016-0018, 0074]. Claim Rejections - 35 USC § 103 9. 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. 10. Claim(s) 3-4, 6, and 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Aurandt et al. (US Patent Application Publication 2017/0058300 A1; examiner cited) in view of Kohl et al. (CA 2780589, 2012; examiner cited). 11. The relevant teachings of Aruandt et al. as applied to claims 1-2, 5, 7, 9-11, 13-14, 16, and 18-20 are set forth in the 102(a)(1) rejection above. With respect to claims 3-4, 6, and 8, Aurandt et al. teach a method for producing biogas, comprising: (a) introducing a feedstock comprising clarified thin stillage (CTS) or clarified thin stillage syrup (CTS syrup) to an anaerobic digester; and (b) digesting the anaerobic digester to produce biogas such as methane [see Abstract; Figures 3-5; paragraphs 0066-0075]. Aurandt et al. teach clarified thin stillage and clarified thin stillage syrup low in suspended solids [see Abstract; paragraphs 0066-0078]. However, Aurandt et al. does not teach the method of claims 3-4, 6 and 8 with the claimed ranges of wt% of suspended solids in the clarified thin stillage. Kohl et al. teach methods for clarifying thin stillage to produce one or more reduced suspended solid streams in the range of 3% to 15% by weight and a lower viscosity for further processing to produce a bio-oil product [see Abstract; p. 10]. Kohl et al. teach that the advantages of this method is reduction of viscosity allows for more efficient dewatering, ease of concentrating and reduction in operating costs [see p. 3, bottom]. Before the effective filing date of the claimed invention, it would have been obvious for one of ordinary skill in the art to combine the teachings of Aurandt et al. and Kohl et al. according to the teachings of Kohl et al. to reduce the suspended solids content of the clarified thin stillage in the methods of Aurandt et al. because both Aurandt et al. and Kohl et al. are concerned with the reduction of suspended solids in thin stillage streams for the production of downstream products following ethanol fermentation. One of ordinary skill in the art would have had a reasonable expectation of success, a reasonable level of predictability, and would have been motivated to combine the teachings of Aurandt et al. and Kohl et al. because Kohl et al. acknowledges that this method reduces viscosity allowing for more efficient dewatering, ease of concentrating and reduction in operating costs. Furthermore, MPEP 2144.05.II.A states “[g]enerally 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)”. In the instant case, one of ordinary skill in the art would desire to optimize the % of total solids in order to maximize the production of biogas. 12. Claim 12 is rejected under 35 U.S.C. 103 as being unpatentable over Aurandt et al. (US Patent Application Publication 2017/0058300 A1; examiner cited). 13. The relevant teachings of Aruandt et al. as applied to claims 1-2, 5, 7, 9-11, 13-14, 16, and 18-20 are set forth in the 102(a)(1) rejection above. With respect to claim 12, Aurandt et al. teach the method wherein the digesting is performed using a hydraulic retention time of less than 24 hours [see paragraph 0077] and teach that the design of the digester must be such that the solids retention time is greater than the hydraulic retention time [see paragraph 0077]. Although Aurandt et al. does not explicitly theca that the solids retention time is at least 20 days, MPEP 2144.05.II.A states “[g]enerally 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)”. In the instant case, one of ordinary skill in the art would desire to optimize the solids retention time in order to maximize the production of biogas. 14. Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Aurandt et al. (US Patent Application Publication 2017/0058300 A1; examiner cited) in view of Zhang et al. (Bioresource Technology, 2019; examiner cited). 15. The relevant teachings of Aruandt et al. as applied to claims 1-2, 5, 7, 9-11, 13-14, 16, and 18-20 are set forth in the 102(a)(1) rejection above. With respect to claim 15, Aurandt et al. teach the method wherein the purifying comprises separating CO2 from the biogas to produce a CO2 rich stream and a methane rich stream [see paragraph 0083]. However, Aurandt et al. does not teach the method of claim 15, wherein the CO2-rich stream is further directed to a carbon capture process or sequestration process. Zhang et al. teach the simultaneous in situ sequestration of CO-2 and methane production by wollastonite addition in an anaerobic digester as an effective method for sequestration of CO2 and methane production enhancement [see Abstract; p. 196; p. 200, column 1]. Before the effective filing date of the claimed invention, it would have been obvious for one of ordinary skill in the art to combine the teachings of Aurandt et al. and Zhang et al. according to the teachings of Zhang et al. to include CO2 sequestration in the anaerobic digestion methods of Aurandt et al. because Aurandt et al. teach methods for the production and separation of methane and carbon dioxide using anerobic digesters of clarified thin stillage streams. Zhang et al. teach that in situ sequestration of CO-2 during anerobic digestion for methane production enhances the methane production process. One of ordinary skill in the art would have had a reasonable expectation of success, a reasonable level of predictability, and would have been motivated to combine the teachings of Aurandt et al. and Zhang et al. because Zhang et al. acknowledges that in situ sequestration of CO-2 during anerobic digestion for methane production enhances the methane production process. Therefore, the above invention would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention. 16. Claim 17 is rejected under 35 U.S.C. 103 as being unpatentable over Aurandt et al. (US Patent Application Publication 2017/0058300 A1; examiner cited) in view of Makaryan et al. (Energies, 03/20/2022; examiner cited). 17. The relevant teachings of Aurandt et al. as applied to claims 1-2, 5, 7, 9-11, 13-14, 16, and 18-20 are set forth in the 102(a)(1) rejection above. With respect to claim 17, Aurandt et al. teach the method wherein the methane rich stream is further purified to produce renewable natural gas [see paragraph 0083]. However, Aurandt et al. does not teach the method of claim 17, further comprising blending the RNG with natural gas. Makaryan et al. teach that the blending of methane with hydrogen (natural gas) in internal combustion engines improves their performance and emission characteristics [see Abstract; p. 2, paragraph 3]. Before the effective filing date of the claimed invention, it would have been obvious for one of ordinary skill in the art to combine the teachings of Aurandt et al. and Makaryan et al. according to the teachings of Makaryan et al. to blend the methane from the anaerobic digestion methods of Aurandt et al. with natural gas because Aurandt et al. teach methods for the production and separation of methane and carbon dioxide using anerobic digesters of clarified thin stillage streams. Makaryan et al. teach that the blending of methane with hydrogen (natural gas) in internal combustion engines improves their performance and emission characteristics. One of ordinary skill in the art would have had a reasonable expectation of success, a reasonable level of predictability, and would have been motivated to combine the teachings of Aurandt et al. and Makaryan et al. because Zhang et al. Makaryan et al. acknowledges that that the blending of methane with hydrogen (natural gas) in internal combustion engines improves their performance and emission characteristics. Therefore, the above invention would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention. Conclusion 18. Status of the claims: Claims 1-20 are pending. Claims 1-20 are rejected. No claims are in condition for an allowance. Any inquiry concerning this communication or earlier communications from the examiner should be directed to PAUL J HOLLAND whose telephone number is (571)270-3537. The examiner can normally be reached Monday to Friday from 8AM to 5PM. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Manjunath Rao can be reached at 571-272-0939. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /PAUL J HOLLAND/Primary Examiner, Art Unit 1656
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Prosecution Timeline

Apr 05, 2024
Application Filed
Mar 05, 2026
Non-Final Rejection — §102, §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
58%
Grant Probability
99%
With Interview (+65.3%)
3y 1m
Median Time to Grant
Low
PTA Risk
Based on 764 resolved cases by this examiner. Grant probability derived from career allow rate.

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