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 the Application
Receipt of the Response and Amendment after Non-Final Office Action filed 02/06/2026 is acknowledged.
The status of the claims upon entry of the present amendment stands as follows:
Pending claims: 1-17
Withdrawn claims: None
Previously canceled claims: None
Newly canceled claims: 2 and 3
Amended claims: 1 and 4
New claims: None
Claims currently under consideration: 1 and 4-17
Currently rejected claims: 1 and 4-17
Allowed claims: None
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1 and 4-17 are rejected under 35 U.S.C. 103 as being unpatentable over Jennewein (U.S. 2016/0333042 A1) in view of DeFrees (U.S. 6,454,946 B1), Parekh (U.S. 2015/0329927 A1), and Drouillard et al. (Drouillard et al., “Efficient synthesis of 6’-sialyllactose, 6,6’-disialyllactose, and 6’-KDO-lactose by metabolically engineered E. coli expressing a multifunctional sialyltransferase from the Photobacterium sp. JT-ISH-224,” Carbohydrate Research, 345 (2010) 1394-1399), as evidenced by Baudouin (U.S. 2010/0038313 A1) and HMDB (Disialyllactose entry on “Human Metabolome Database”, obtained from https://hmdb.ca/metabolites/HMDB0006692, 2025).
Regarding claim 1, Jennewein discloses a method for the purification of neutral HMOs from other carbohydrates in a fermentation broth obtained from a fermentation ([0001], [0017], [0018], [0023]-[0024]), wherein the method comprises subjecting an aqueous solution obtained from separating biomass from a fermentation broth comprising the HMOs and other carbohydrates to nanofiltration ([0018], [0023]-[0024], [0034]), wherein separating biomass from the fermentation broth comprises at least one ultrafiltration ([0029]).
Jennewein does not disclose the purification as applying to sialyllactose, and specifically, separating sialyllactose from disialyllactose, or the nanofiltration as comprising subjecting the solution to two membrane filtrations using membranes having the claimed molecular weight cut-off ranges, where the first retentate is subjected to the second filtration, wherein disialyllactose is retained and sialyllactose passes into the filtrate.
However, DeFrees discloses a method for purifying a carbohydrate compound from a feed solution comprising the reaction mixture (C3, L13-L16), where the carbohydrate may be sialyllactose and the purification occurs via nanofiltration (C5, L6-L30) with a first step that retains the sialyllactose and expels smaller molecules (C6, L11-L21) and an additional step that retains larger molecules, such as proteins, and expels the sialyllactose (C8, L1-L16). Baudouin discloses that sialyllactose has a molecular weight of 633 ([0003]). HMDB discloses disialyllactose has a molecular weight of 925 (p. 2, “Average Molecular Weight”). Parekh discloses a method for the purification of sugars via multiple nanofiltration steps ([0006], [0008], [0226]), where the first nanofiltration membrane may have a molecular weight cut-off of about 0.25-0.5 kDa ([0263]) and the second nanofiltration membrane may have a molecular weight cut-off of about 0.7 kDa ([0269]). Drouillard et al. discloses an enzymatic synthesis method wherein disialyllactose is produced together with sialyllactose (pp. 1394-1395, bridging paragraph; pp. 1396-1397, bridging paragraph).
It would have been obvious to one having ordinary skill in the art to perform the purification method of Jennewein to purify sialyllactose from other carbohydrates, including disialyllactose, via the utilization of two nanofiltration steps with membranes having molecular weight cut-offs in the ranges of about 300-500 Da and about 600-800 Da, respectively. First, Jennewein teaches generally that enzymatic methods for producing HMOs yield complex mixtures of compounds ([0005]) for which the disclosed purification method utilizing nanofiltration is suited for concentrating and purifying the target HMO ([0014]). Though the reference focuses on neutral HMOs ([0015]), a skilled practitioner would recognize that the method would be applicable to other HMOs as well, given the breadth that Jennewein discusses the problem related to purification of enzymatic processes for producing HMOs ([0005], [0014]). A skilled practitioner would thus be motivated to consult DeFrees for further instruction regarding HMOs other than neutral HMOs. The disclosure in DeFrees that sialyllactose may be purified from a reaction mixture via nanofiltration (C3, L13-L16; C5, L6-L30) at least suggests to a skilled practitioner that the process of Jennewein would be suited to purify sialyllactose in addition to neutral HMOs. Performing the method of Jennewein for the purpose of purifying sialyllactose would thus be obvious.
DeFrees further teaches that purification of sialyllactose involves expelling smaller molecules in a first step and a second step of separating larger molecules, where sialyllactose is expelled by a membrane (C6, L11-L21; C8, L1-L16). Since Baudouin teaches that sialyllactose has a molecular weight of 633 ([0003]), a skilled practitioner would recognize that a first nanofiltration membrane would need to have a molecular weight cutoff smaller than that of sialyllactose and a second nanofiltration membrane would need to have a molecular weight cutoff larger than that of sialyllactose. The disclosed nanofiltration membrane molecular weight cut-off values in Parekh of about 0.25-0.5 kDa (i.e., 250-500 Da) ([0263]) and about 0.7 kDa (i.e., 700 Da) ([0269]) meet those criteria, which renders such values obvious. The claimed membrane molecular weight cut-off ranges of about 300-500 and about 600-800 Da and the claimed sequence of a performing the second filtration on the first retentate would thus be obvious to a skilled practitioner. Since the molecular weight of disialyllactose is 925 as shown in HMDB, it would be retained on the second nanofiltration membrane, while the sialyllactose would pass into the filtrate. Such a result would be expected to occur using such membranes whether the disialyllactose was specifically identified or not simply based on its inherent molecular weight, especially since DeFrees teaches that sialyllactose may be purified “to essentially 100% purity” (C5, L24-L26).
As for the presence of disialyllactose in the fermentation broth initially, Jennewein discloses enzymatic/fermentative approaches for producing HMOs but notes such methods “yield complex mixtures of oligosaccharides i.e. the desired product is contaminated with starting material such as lactose, biosynthetic intermediates and substrates such as individual monosaccharides and polypeptides etc. ([0005]). A skilled practitioner would be motivated to consult Drouillard et al. for clarification regarding such types of contaminants. Since Drouillard et al. discloses the separation of disialyllactose from sialyllactose following an enzymatic synthesis method (pp. 1394-1395, bridging paragraph; pp. 1396-1397, bridging paragraph; p. 1399, §4.6), a skilled practitioner would find the separation of disialyllactose in particular from a fermentation broth as discussed in Jennewein to be obvious.
As for claim 4, Jennewein discloses separation of the biomass from the fermentation broth as comprising ultrafiltration ([0029]). MPEP 2144.04 VI B states: “mere duplication of parts has no patentable significance unless a new and unexpected result is produced.”, which is understood to apply to duplication of method steps as well. Simply performing two ultrafiltration steps that are not further limited in terms membranes, duration, or attained results does not impart any new or unexpected result. The claimed performance of two ultrafiltration steps is thus obvious to a skilled practitioner.
As for claim 5, Jennewein discloses treating the aqueous solution with a cation exchange resin and an anion exchange resin ([0018]).
As for claim 6, Jennewein discloses the method as further comprising dialysis ([0018]).
As for claim 7, Jennewein discloses the purity of the HMO as being within the claimed ranges ([0025]), which would apply when sialyllactose is purified as well.
As for claim 8, DeFrees is considered to render obvious the purification of sialyllactose in general (C5, L6-L30), which renders obvious the purification of 3’-SL and 6’-SL.
As for claims 9-17, Jennewein discloses the purity of the HMO in the aqueous solution prior to purification and after purification as being within the claimed ranges ([0025]), which would apply when sialyllactose is purified as well.
Response to Arguments
Claim Rejections - 35 U.S.C. § 103 of claims 1-17 over Jennewein, DeFrees, Parekh, and Drouillard et al., as evidenced by Baudouin and HMDB: Applicant’s arguments have been fully considered but they are not persuasive.
Applicant first argued that Jennewein teaches at paragraph [0014] only that nanofiltration is for concentration and salt removal but not removal of carbohydrates (Applicant’s Remarks, p. 2, ¶5-¶6). Applicant asserted that Jennewein provides alternative solutions for removal of larger oligosaccharides in paragraphs, such as adsorption to activated carbon ([0032]) and enzymatic degradation ([0036]) (Applicant’s Remarks, p. 3, ¶1). Applicant concluded that because “Jennewein already provides a complete solution to carbohydrate removal from the ‘complex’ mixtures provided therein”, a skilled practitioner would not have consulted any additional reference for instruction on filtration (Applicant’s Remarks, p. 3, ¶2).
However, Examiner maintains that the statement in the claim rejection is accurate: “Jennewein teaches generally that enzymatic methods for producing HMOs yield complex mixtures of compounds ([0005]) for which the disclosed purification method utilizing nanofiltration is suited for concentrating and purifying the target HMO ([0014]).” Paragraph [0014] clearly indicates that “[i]n the developed process for the efficient purification of food-grade human milk oligosaccharides from microbial fermentation, nanofiltration is employed…” The statement in the claim rejection did not indicate that the purification of the target HMO via nanofiltration was based on the removal of carbohydrates. Examiner thus maintains that the statement is accurate and adequate for all that is relied on in the present claim rejection.
Paragraph [0005] indicates contaminants of the target compound mixture may include “lactose, biosynthetic intermediates and substrates such as individual monosaccharides and polypeptides etc.” However, paragraph [0032] indicates suitability only for the removal of “larger oligosaccharides”, and paragraph [0036] indicates degradation of “unwanted intermediates, substrates and/or oligosaccharides”, which would presumably only result in smaller molecules that nonetheless remain in the mixture. Neither paragraph indicates actual removal of monosaccharides or disaccharides, which undermines Applicant’s arguments. Examiner maintains that adequate motivation was detailed as to why a skilled practitioner would consult the cited secondary references.
Applicant then argued that DeFrees discloses a purification sequence that differs from that presently claimed and additionally relies on improper hindsight (Applicant’s Remarks, p. 3, ¶3 – p. 4, ¶2). Applicant alleged that the citation to column 6 applies only to the selection of a membrane but not actually the use of such a membrane in a purification step (Applicant’s Remarks, p. 4, ¶1). Applicant then asserted that the citation to column 8 applies to an alternative first step to that disclosed previously at column 6 and that the method disclosed in DeFrees is thus a different sequence than that claimed (Applicant’s Remarks, p. 4, ¶2).
However, the claim rejection does not rely on DeFrees in the manner that underlies Applicant’s argument. At paragraph 10 of the Office Action filed 08/06/2025, Examiner stated: “DeFrees further teaches that purification of sialyllactose involves expelling smaller molecules in a first step and a second step of separating larger molecules, where sialyllactose is expelled by a membrane (C6, L11-L21; C8, L1-L16).” The “first step” and “second step” were not intended to imply a sequence but were instead intended to convey a baseline “purification step” (the “first” step) and an “additional step” (the “second” step), without any consideration of sequence. Paragraph 22 of that Office Action confirms this reading, reciting “[t]he reference later describes a preliminary refining step that may be applied even before the process beginning with the ‘starting point’ of column 6”. Parekh is relied on for additional clarification regarding the sequence of steps, where the first nanofiltration membrane may have a molecular weight cut-off of about 0.25-0.5 kDa ([0263]) and the second nanofiltration membrane may have a molecular weight cut-off of about 0.7 kDa ([0269]).
Regardless, MPEP 2144.04 IV C states: “selection of any order of performing process steps is prima facie obvious in the absence of new or unexpected results”. Performing either step of a two-step filtration process first would be obvious; the MWCO values would simply dictate whether the target material is in the retentate or permeate after the first filtration that would need to be further processed as part of the second filtration. Applicant’s argument regarding the sequence of process steps is thus unpersuasive.
Further, any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made, and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971). Examiner maintains that the claim rejection relies only on knowledge that was within the level of ordinary skill at the time the claimed invention was made and does not include knowledge gleaned only from Applicant’s disclosure, and therefore, that the claim rejection does not rely on improper hindsight.
Applicant then argued that the citation to column 8 refers to the removal of proteins not carbohydrates (Applicant’s Remarks, p. 4, ¶3).
However, DeFrees et al. refers to “proteins and other macromolecules to be removed from the solution” (C8, L9-L10), which would encompass larger carbohydrate components.
Applicant next argued that a combination of Jennewein and DeFrees does not disclose ultrafiltration of a fermentation broth into biomass and an aqueous solution that is subsequently subject to two filtration steps (Applicant’s Remarks, p. 4, ¶4).
As noted in the claim rejection, though, Jennewein discloses separating biomass from a fermentation broth that comprises ultrafiltration ([0029]). Purification via two subsequent nanofiltration steps would be obvious in view of the additional instruction in DeFrees.
Applicant then argued that a practitioner would not have modified Jennewein to include purification steps as taught in DeFrees, since Jennewein already discloses “processes for removing unwanted components from the complex mixtures therein” (Applicant’s Remarks, p. 5, ¶1).
However, Examiner maintains that the instruction in DeFrees valuably supplements the instruction in Jennewein and that a skilled practitioner would recognize the benefit of implementing such instruction into a nanofiltration process aimed toward “efficient purification of food-grade human milk oligosaccharides” as expressed in Jennewein ([0014]). That Jennewein may disclose additional purification processes does not preclude additional reliance on DeFrees regarding implementation of nanofiltration as a purification technique.
Applicant next argued that the disclosure of Parekh is not adequately specific to render obvious the claimed membrane parameters (Applicant’s Remarks, p. 5, ¶2 - ¶3).
In response to Applicant's arguments against Parekh individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Applicant’s argument regarding only the disclosure of Parekh disregards the instruction of DeFrees that sialyllactose in particular may be purified to “essentially 100% purity” (C5, L24-L26), as well as that of the evidentiary references that show the molecular weights of sialyllactose and disialyllactose. A skilled practitioner attempting to isolate a target compound with a known molecular weight would select membrane cutoff values that achieve that goal via the selection of suitable membranes to separate known contaminants. Parekh is adequate for all that is relied on in showing that purification of sugars may be achieved via nanofiltration membranes with molecular weight cutoff values that fall within the claimed ranges. Applicant’s argument is unpersuasive.
Applicant concluded that the combination of cited prior art would not provide a skilled practitioner with a reasonable expectation of success (Applicant’s Remarks, p. 5, ¶4 – p. 6, ¶1).
However, the stated aim of the claimed method is “for purification of a sialyllactose from one or more other carbohydrates”, DeFrees discloses purification of sialyllactose “up to essentially 100% purity” (C5, L24-L26). Examiner maintains that a skilled practitioner would thus have a reasonable expectation of success of performing a purification method in order to purify sialyllactose. Applicant’s argument is unpersuasive.
Applicant asserted that the additionally-cited references do not remedy the alleged deficiencies of Jennewein, DeFrees, and Parekh (Applicant’s Remarks, p. 6, ¶2 – ¶4).
Examiner maintains that no deficiency exists as related to the disclosure of Jennewein, DeFrees, and Parekh, and that the additionally-cited references are adequate for all that is relied on in the present claim rejections. Examiner maintains that the prima facie showing of obviousness is adequate and proper.
The rejections of claims 1 and 4-17 have been maintained herein.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Claims 1 and 4-17 are rejected.
No claims are allowed at this time.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JEFFREY P MORNHINWEG whose telephone number is (571)270-5272. The examiner can normally be reached 8:30AM-5:00PM.
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/JEFFREY P MORNHINWEG/Primary Examiner, Art Unit 1793
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