DETAILED ACTION
Applicant’s amendment submitted on 1/13/2026 is acknowledged. Claims 5-6 and 8 are currently amended. Claim 14 is newly added. Claims 1-4, 7, and 10-13 are canceled. Claims 5-6, 8-9, and 14 are pending in the instant application.
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 .
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 1/13/2026 has been entered.
Priority
The instant application claims foreign priority to BR10 2022 024357 3, filed 11/29/2022, and a receipt of a certified copy of that document is acknowledged. However, no English translation of the foreign priority document has been provided to perfect priority, therefore the effective filing date of the instant claims is considered to be the filing date of the instant application, 5/10/2023. See 37 CFR 1.55.
Response to Amendment
Applicant’s amendment in paragraphs [0020] and [0024] overcome the objection to the specification previously set forth in the Final Rejection mailed on 10/22/2025. Accordingly, the objection to the specification is withdrawn.
Claim Objections
Claims 5 and 6 are objected to because of the following informalities:
Claim 5 recites an improper dash after the first recitation of “the” in line 3, which should be removed.
In claim 5, the conjunction “and” is missing at the end of line 7.
Claim 6 recites “salt water” and “fresh water” in lines 2-3, whereas “saltwater” and “freshwater” are the proper spelling for these terms.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
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.
Claim 6 is 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 6 recites the microalgae suspension is a source of fresh water in lines 1-3. Claim depends from claim 5. Claim 5 recites the microalgae suspension has a salt concentration equal to or greater than 5 g/L. It is not clear how the salt concentration of the microalgae suspension is at least 5 g/L and can also be freshwater. Hazeltine (Field Guide of Appropriate Technology, 2003, Ch. 3 – Food, pp.270-480) defines freshwater as having a salt concentration less than 1 g/L (see p.380, 2nd passage). Thus, it is not clear how the microalgae suspension can be a source of freshwater but also have a salt concentration of at least 5 g/L as required by claim 5, since freshwater has a salt concentration of less than 1 g/L.
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 5-6 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Savvidou et al. (Nanomaterials, 2021, Vol. 11(1614), p.1-18; of record) in view of Promega (Buffers for Biochemical Reactions; 2011), Figler et al. (Water, 2019, Vol. 11(2527), p.1-17; of record), and Khan et al. (Sci. Rep., 2021, Vol. 11(1), p.1-10; of record) and as evidenced by AAT Bioquest – Potassium Phosphate (retrieved from < https://www.aatbio.com/resources/buffer-preparations-and-recipes/potassium-phosphate-ph-5-8-to-8-0>; of record) and Li et al. (J. Environ. Chem. Engin., 2022, Vol. 10, p.1-12; of record).
Regarding claim 5, Savvidou teaches magnetic harvesting of the microalga Chlorella Vulgaris (see Abstract). Savvidou teaches the C. vulgaris strain was grown in a medium comprising K2HPO4 and KH2PO4, and the medium was kept at a pH of 6.8 to 7 (see p.3, 2nd paragraph). AAT Bioquest provides evidence that mixtures of K2HPO4 and KH2PO4 form potassium phosphate buffers (see AAT Bioquest – Potassium Phosphate). The culture medium has a total salt concentration of 1524 mg/L (1.524 g/L) composed of the salts: NaNO3, CaCl2, MgSO4, K2HPO4, KH2PO4, NaCl, Na2EDTA, FeCl3, MnCl2, ZnCl2, CoCl2, and Na2MoO4 (see p.3, 2nd paragraph). Savvidou teaches the magnetic harvesting of C. vulgaris comprises fixing the pH of the microalgal cultivation at a desired value, mixing 10 mL of microalgae cultivation with a given amount of synthesized magnetite (Fe3O4---) magnetic particles in order to facilitate the flocculation between the algal cells and the magnetic particles, and the application of a strong magnetic field to separate the flocs from the cultivation medium, reading on adding magnetic nanoparticles to the suspension and applying an external magnetic field, thus promoting flocculation of the microalgae as recited in claim 5 (see paragraph bridging p.2-3, p.3, 1st and 2nd paragraphs, and p.4, 6th paragraph). Savvidou further teaches the optimal pH for magnetic harvest of C. vulgaris is at a pH of 3 (see p.8, last paragraph, and paragraph bridging p.9-10). Li provides evidence that at low pH values, the surface functional groups of microalgae is protonated (see p.4, right column, 2nd paragraph). Therefore, adjusting the pH of the C. vulgaris cultivation to a pH of 3 is expected to protonate the cell surface of C. vulgaris as evidenced by Li.
Savvidou does not teach adding citrate buffer to the suspension, the magnetic nanoparticles are of bacterial origin, or that the suspension has a salt concentration equal to or greater than 5 g/L.
Promega teaches buffers function to resist changes in hydrogen ion concentration as a result of internal and environmental factors (see p.15-1, left column, 2nd passage). Promega teaches citrate buffer as an acidic buffer that can be produced at a pH of 3 to a pH of 6.2 (see p.15-4, B. Preparation of Citrate Buffer (pH 3.0-6.2)).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have buffered the Chlorella vulgaris magnetic harvesting solution, as taught by Savvidou, using citrate buffer at a pH of 3.0, as taught by Promega, to arrive at the claimed invention. One of ordinary skill in the art would have been motivated to prevent changes in hydrogen ion concentration and keep the pH of the harvesting solution constant at 3.0, yielding predictable results.
Promega does not teach the magnetic nanoparticles are of bacterial origin or that the suspension has a salt concentration equal to or greater than 5 g/L.
Figler tested the salt tolerance of 9 green microalgae species including Chlorella vulgaris, and discloses that C. vulgaris could tolerate and grow significantly in the presence of 5000 mg/L (5 g/L – see p.5, 2nd paragraph). Figler further teaches 50% growth inhibition was observed for C. vulgaris in a salt concentration of 29,233 mg/L (29.233 g/L) (see p.6, 1st paragraph).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to adjust the salt concentration of the culture medium for growing C. vulgaris, as taught by Savvidou, to a salt concentration within 5 g/L and 29.233 g/L, as taught by Figler, to arrive at the claimed invention. One of ordinary skill in the art would have recognized from Figler that C. vulgaris not only tolerates but grows significantly in a salt concentration of 5 g/L and it isn’t until 29.233 g/L salt concentration that 50% growth inhibition is exhibited, yielding predictable results. One of ordinary skill in the art would have had a reasonable expectation of success increasing the salt concentration of the culture medium of Savvidou since each of Savvidou and Figler teach the cultivation of C. vulgaris.
Figler does not teach that the magnetic nanoparticles are of bacterial origin.
Khan teaches extracting and purifying magnetic nanoparticles synthesized in Pseudomonas aeruginosa (see Abstract). Khan teaches isolated material magnetite nanoparticles demonstrated magnetic behavior (see passage bridging p.4-5).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have substituted magnetite nanoparticles isolated from Pseudomonas aeruginosa, as taught by Khan, for the magnetite magnetic particles used in the Chlorella vulgaris magnetic harvesting protocol, as taught by Savvidou, to arrive at the claimed invention. One of ordinary skill in the art would have been substituting an equivalent magnetite magnetic particle for the same purpose, as set forth in MPEP § 2144.06(II), with a reasonable expectation of success since Khan disclosed the magnetite nanoparticles obtained from P. aeruginosa demonstrated magnetic behavior.
Regarding claim 6, the magnetic harvest solution comprises 10 mL of the microalgae cultivation which has a salt concentration within 5 g/L and 29.233 g/L as discussed above in the rejection of claim 5. Therefore, the microalgae suspension reads on a source of saltwater.
Regarding claim 8, Savvidou in view of Promega, Figler, and Khan as evidenced by AAT Bioquest and Li teach the addition of citrate buffer at a pH of 3.0, the acidic pH resulting in protonation of the cell surface of Chlorella vulgaris. Savvidou demonstrated C. vulgaris harvesting at a pH of 3, 5, and 7, finding that a pH of 3 resulted in the best harvesting efficiency while a pH of 7 was still proved to be satisfactory (see p.8, last paragraph, p.9, 1st paragraph,-p.10,1st passage, Fig. 3C, and Table 2). Thus, it would have been obvious to optimize the pH of the microalgae magnetic harvesting suspension by the addition of the citrate buffer and arrive at pH of 3.1. One of ordinary skill in the art would have been optimizing within a range of acceptable pH values yielding satisfactory harvesting, yielding predictable results.
Therefore, claims 5-6 and 8 are prima facie obvious over Savvidou in view of Promega, Figler, and Khan.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Savvidou et al. (Nanomaterials, 2021, Vol. 11(1614), p.1-18; of record) in view of Promega (Buffers for Biochemical Reactions; 2011), Figler et al. (Water, 2019, Vol. 11(2527), p.1-17; of record), and Khan et al. (Sci. Rep., 2021, Vol. 11(1), p.1-10; of record) and as evidenced by AAT Bioquest – Potassium Phosphate (retrieved from < https://www.aatbio.com/resources/buffer-preparations-and-recipes/potassium-phosphate-ph-5-8-to-8-0>; of record) and Li et al. (J. Environ. Chem. Engin., 2022, Vol. 10, p.1-12; of record), as applied to claims 5-6 and 8 above, and further in view of Fraga-Garcia et al. (Nanomaterials, 2018, Vol. 8(292), p.1-17; of record).
Savvidou in view of Promega, Figler, and Khan as evidenced by AAT Bioquest and Li teach the invention of claim 5 as outlined in the rejection above.
Regarding claim 9, Savvidou in view of Figler and Khan do not teach adding the magnetic particles of bacterial origin at a concentration between 50 and 100 μg/mL.
Fraga-Garcia teaches a method of magnetic harvesting of Chlorella vulgaris using bare iron oxide nanoparticles and teaches a concentration of 5 to 50 μg/mL is considered very low, while higher harvesting efficiencies are reached at higher concentrations (see Abstract, p.3, 1st-2nd paragraphs, and p.6, last paragraph).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have used a concentration of at least 50 μg/mL and further optimized the concentration of bare iron oxide nanoparticles, as taught by Fraga-Garcia, in the method of harvesting Chlorella vulgaris, as taught by Savvidou in view Promega, Figler, and Khan, to arrive at the claimed invention. One of ordinary skill in the art would have been motivated to optimize the concentration to above 50 μg/mL because Fraga-Garcia discloses this is considered a very low concentration for harvesting Chlorella vulgaris and that higher concentrations are more efficient, yielding predictable results. Therefore, claim 9 is prima facie obvious over Savvidou in view of Promega, Figler, Khan, and Fraga-Garcia.
Claim 14 is rejected under 35 U.S.C. 103 as being unpatentable over Savvidou et al. (Nanomaterials, 2021, Vol. 11(1614), p.1-18; of record) in view of Promega (Buffers for Biochemical Reactions; 2011), Figler et al. (Water, 2019, Vol. 11(2527), p.1-17; of record), and Khan et al. (Sci. Rep., 2021, Vol. 11(1), p.1-10; of record) and as evidenced by AAT Bioquest – Potassium Phosphate (retrieved from < https://www.aatbio.com/resources/buffer-preparations-and-recipes/potassium-phosphate-ph-5-8-to-8-0>; of record) and Li et al. (J. Environ. Chem. Engin., 2022, Vol. 10, p.1-12; of record), as applied to claims 5-6 and 8 above, and further in view of Nguyen et al. (BioResources, 2021, Vol. 16(2), pp.-3469-3493).
Savvidou in view of Promega, Figler, and Khan as evidenced by AAT Bioquest and Li teach the invention of claim 5 as outlined in the rejection above.
Figler demonstrates the cultivation of C. vulgaris in a salt concentration of 29.233 g/L (see p.5, 2nd paragraph and p.6, 1st paragraph).
Savvidou, Promega, Figler, and Khan do not teach wherein the salt concentration of the suspension is equal to greater than 40 g/L.
Nguyen teaches an artificial seawater medium for cultivation of marine algae having a 40 g/L concentration of sea salt (see p.3473, 2nd paragraph). Nguyen further teaches magnetic flocculation of the marine microalgae Tetraselmis using an aliquot of the cultivation medium (see p.3473, last paragraph, p.3485, 1st paragraph,-p.3487, 1st paragraph, Table 2, and Figs. 10-11).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to increase the salt concentration of the cultivation medium to 40 g/L, as taught by Nguyen, in the cultivation medium of the Chlorella vulgaris, as taught by Savvidou, to arrive at the claimed invention. One of ordinary skill in the art would have been motivated increase the salt concentration of the culture medium because Nguyen teaches successful magnetic flocculation of microalgae cultivated in a culture medium with a salt concentration of 40 g/L, yielding predictable results. One of ordinary skill in the art would have had a reasonable expectation of success because Figler teaches Chlorella vulgaris has a high salt tolerance. Thus, claim 14 is prima facie obvious over Savvidou in view of Promega, Figler, Khan, and Nguyen.
Response to Arguments
Applicant's arguments filed 1/13/2026 have been fully considered but they are not persuasive.
In Applicant’s Remarks, see p.5, 3rd paragraph,-p.8, 3rd paragraph, Applicant argues that none of the cited prior art teach protonating a cell surface of the microalgae by adding a citrate buffer to the suspension. Applicant further argues that the combination of Savvidou and Figler would render the invention of Savvidou unsatisfactory for its intended purpose because increasing the salt concentration would reduce the effectiveness of the magnetic harvesting process taught by Savvidou, as demonstrated by the results displayed in Figure 22 of the instant application. Applicant further argues that it would not be obvious to substitute magnetite nanoparticles isolated from Pseudomonas aeruginosa, as taught by Khan, for the magnetite magnetic particles used in the Chlorella vulgaris magnetic harvesting protocol, as taught by Savvidou. Applicant argues the performance of NMOBs were demonstrated to be significantly superior in promoting cell agglomeration/concentration when an external magnetic field is applied as compared to synthetic magnetic particles. Applicant further argues the use of NMOBs provides unexpected results in hypersaline conditions as demonstrated in Figures 20-22 of the instant application. This is not found persuasive.
The rejection set forth above relies on Promega to teach the claimed limitation of a citrate buffer. Promega teaches buffers function to resist changes in hydrogen ion concentration as a result of internal and environmental factors (see p.15-1, left column, 2nd passage). Promega teaches citrate buffer as an acidic buffer that can be produced at a pH of 3 to a pH of 6.2 (see p.15-4, B. Preparation of Citrate Buffer (pH 3.0-6.2)). Since Savvidou teaches the optimal pH for magnetic harvest of C. vulgaris is at a pH of 3, it would have been obvious to utilize a 3.0 citrate buffer, as taught by Promega, to prevent changes in hydrogen ion concentration and keep the pH of the harvesting solution constant, yielding predictable results. Li provides evidence that at low pH values, the surface functional groups of microalgae is protonated (see p.4, right column, 2nd paragraph). Thus, the rejection set forth above obviates the claimed limitation of protonating a cell surface of the microalgae by adding a citrate buffer to the suspension. Applicant has not provided evidence that modifying the C. vulgaris harvesting method of Savvidou to utilize magnetite nanoparticles from Pseudomonas aeruginosa, as taught by Khan, would render the invention of Savvidou inoperable. The method of Savvidou utilizes synthesized magnetite (Fe3O4---) magnetic particles for the harvest of C. vulgaris (see paragraph bridging p.2-3, p.3, 1st and 2nd paragraphs, and p.4, 6th paragraph). Khan teaches extracting and purifying magnetic nanoparticles synthesized in Pseudomonas aeruginosa (see Abstract). Khan teaches isolated material magnetite nanoparticles demonstrated magnetic behavior (see passage bridging p.4-5). Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have substituted magnetite nanoparticles isolated from Pseudomonas aeruginosa, as taught by Khan, for the magnetite magnetic particles used in the Chlorella vulgaris magnetic harvesting protocol, as taught by Savvidou, to arrive at the claimed invention. One of ordinary skill in the art would have been substituting an equivalent magnetite magnetic particle for the same purpose, as set forth in MPEP § 2144.06(II), with a reasonable expectation of success since Khan disclosed the magnetite nanoparticles obtained from P. aeruginosa demonstrated magnetic behavior. Applicant’s arguments that the use of NMOBs in hypersaline conditions of microalgae harvesting is unexpectedly superior to synthetic nanoparticles as demonstrated in Figs. 20-22 of the instant specification are not commensurate in scope with the claimed invention. Figs. 20-22 demonstrate the magnetic harvest of Nannochloropsis in hypersaline conditions using NMOBs; however, the claimed invention is directed specifically to the harvest of Chlorella sp. Furthermore, instant claim 5 does not limit the pH of the solution and broadly recites the salt concentration is equal to or greater than 5 g/L but not necessarily hypersaline as demonstrated in the cited Figures. Thus, Applicant’s arguments of unexpected results are not commensurate in scope with the claimed invention.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JOHN PAUL SELWANES whose telephone number is (571)272-9346. The examiner can normally be reached Mon-Fri 7:30-5:00.
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/J.P.S./ Examiner, Art Unit 1651
/MELENIE L GORDON/ Supervisory Patent Examiner, Art Unit 1651