Ex Parte Adkesson et al

Board of Patent Appeals and Interferences

Nov 30, 2010

10839188 (B.P.A.I. Nov. 30, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte DENNIS MICHAEL ADKESSON,
ALBERT W. ALSOP, TYLER T. AMES, LUIS ALBERTO CHU,
JAMES M.DISNEY, BRYAN C. DRAVIS, PATRICK FITZGIBBON,
JAMES M. GADDY, F. GLENN GALLAGHER,
WILLIAM F. LEHNHARDT, JEFFERSON C. LIEVENSE,
MICHAEL L. LUYBEN, MAYIS SEAPAN, ROBERT E. TROTTER,
GREGORY M. WENNDT, and EUGENE K. YU
__________

Appeal 2010-007746
Application 10/839,188
Technology Center 1600
__________

Before ERIC GRIMES, LORA M. GREEN, and FRANCISCO C. PRATS,
Administrative Patent Judges.

PRATS, Administrative Patent Judge.

DECISION ON APPEAL1

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, or for filing a request for rehearing,
as recited in 37 C.F.R. § 41.52, begins to run from the “MAIL DATE”
(paper delivery mode) or the “NOTIFICATION DATE” (electronic delivery
mode) shown on the PTOL-90A cover letter attached to this decision.
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Application 10/839,188

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This appeal under 35 U.S.C. § 134 involves claims to processes of
purifying 1,3-propanediol from a fermentation broth. The Examiner rejected
the claims as obvious.
We have jurisdiction under 35 U.S.C. § 6(b). We reverse.

STATEMENT OF THE CASE
Claims 1, 3-5, 7-14, and 18-20 are pending and on appeal (App. Br.
3). Claim 1 is representative and reads as follows:
1. A process of purifying biologically-produced
1,3-propanediol from the fermentation broth of a
microorganism able to produce 1,3-propanediol, comprising the
sequential steps of:
(a) subjecting the fermentation broth to filtration;
(b) subjecting the product of step (a) to two ion
exchange purification steps comprising:
i) anionic exchange; and
ii) cationic exchange wherein ionic impurities
are removed;
(c) subjecting the product of step (ii) to chemical
reduction; and
(d) subjecting the product of step (c) to at least two
distillation procedures comprising at least two
distillation columns wherein one of said distillation
columns removes molecules having a boiling point
exceeding the boiling point of 1,3-propanediol and
the other of said distillation columns removes
molecules having a boiling point below the boiling
point of 1,3-propanediol whereby purified
biologically-produced 1,3-propanediol having a
concentration of total organic impurities of less
than about 400, an absorbance at 275 nm of less
than 0.075 and a L*a*b*, b* color value of less
than about 0.15 is produced.

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The sole rejection before us for review is the Examiner’s rejection of
claims 1, 3-5, 7-14, and 18-20 under 35 U.S.C. § 103(a) as obvious over
Fisher,2 Hilaly,3 Haas,4 Mollee,5 Ames,6 and Burch7 (Ans. 4-8).8
OBVIOUSNESS
ISSUE
The Examiner cites Fisher as disclosing a process of purifying sugar
alcohols from a fermentation broth, the process having essentially the same
filtration and anion/cation exchange steps as recited in claim 1 (Ans. 4).
While the Examiner finds that the claimed process differs from Fisher’s
process in a number of ways, the Examiner nonetheless reasons that an
ordinary artisan would have considered the claimed process obvious when
viewing Fisher in light of the other references (id. at 5-8).
Among other reasons, Appellants urge that the Examiner did not show
prima facie obviousness because the cited references would not have
suggested performing step (c) in claim 1, which requires the practitioner to
subject the filtered, anion/cation-exchanged fermentation broth from steps
(a) and (b) to chemical reduction (App. Br. 12). In particular, Appellants
argue, while Haas discloses that chemical reduction by catalytic

2 WO 00/24918 A1 (published May 4, 2000).
3 WO 01/73097 A2 (published October 4, 2001).
4 U.S. Patent No. 5,334,778 (issued August 2, 1994).
5 U.S. Patent Application Publication No. 2004/0198965 (published October
7, 2004).
6 U.S. Patent No. 6,361,983 B1 (issued March 26, 2002).
7 U.S. Patent No. 6,428,767 B1 (issued August 6, 2002).
8 While the Examiner’s Answer lists claims 15-17, 21-24, 26, and 27 as also
being subject to this rejection (Ans. 4), those claims have been canceled
(see, e.g. Advisory Action 1 (October 16, 2009).
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hydrogenation was known in the art to convert 3-hydroxypropionaldehyde
(HPA) to 1,3-propanediol, “[p]urification of 1,3-propanediol via
hydrogenation is simply not disclosed or suggested by Haas” (id.).
The Examiner responds that Haas teaches “the use of hydrogenation
for the removal of carbonyl compounds, which are known to produce color,
to below 500 ppm from 1,3-propanediol. Thus, although Haas et al. do not
explicitly disclose the removal/reduction of the residual carbonyl content as
a means of purification, it is implicitly taught” (Ans. 13).
Appellants reply that Haas describes a specific set of reaction
conditions that produce 1,3-propanediol from HPA by hydrogenation, while
minimizing the residual content of carbonyl impurities in the final product
(Reply Br. 5-6). Therefore, Appellants argue, an ordinary artisan would not
have been prompted to use Haas’ hydrogenation techniques to purify
1,3-propanediol from a fermentation broth, “because 1,3-propanediol has
already been produced biologically” (id. at 6).
In view of the positions advanced by Appellants and the Examiner,
the issue with respect to this rejection is whether an ordinary artisan would
have been prompted to chemically reduce, by catalytic hydrogenation, a
filtered, anion/cation-exchanged, 1,3-propanediol-containing fermentation
broth.
FINDINGS OF FACT (“FF”)
1. Hilaly discloses that 1,3-propanediol (PDO) “is a precursor of
polytrimethylene terephthalate which is a raw material for making polymeric
fiber. Conventionally, ethylene oxide is used to chemically produce PDO.
Ethylene oxide is first converted to 3-hydroxyl-propionaldehyde (3HPA) in
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presence of a cobalt-based catalyst. Then 3HPA is catalytically
hydrogenated to produce PDO” (Hilaly 1 (citation omitted)).
2. Hilaly discloses that “PDO can also be produced biochemically by
fermentation. In these methods, substrates such as glycerol and glucose, for
example, are converted to PDO by microorganisms. The advantage of the
fermentative route is lower raw material cost. Accordingly, there is
considerable interest in making PDO fermentatively” (id. (citations
omitted)).
3. Haas discloses that one problem associated with chemical synthesis of
1,3-propanediol is the presence of undesired impurities in the final product:
In the production of 1,3-propanediol on an industrial
scale by hydrogenation of 3-hydroxypropionaldehyde in
aqueous phase, it has been found that, even under the optimal
reaction conditions . . . with an HPA conversion of substantially
100% and a selectivity approaching 100%, and despite careful
working up of the reaction mixture by distillation and
purification of the 1,3-propanediol by distillation, the
1,3-propanediol still has a residual carbonyl content, expressed
as propionaldehyde, of a few thousand ppm. This high
carbonyl content is extremely troublesome in the production of
poly(1,3-propylene glycol terephthalate) and in the application
of this polymer for the production of fibers by melt spinning
because it leads both to odor emissions and to discoloration of
the fibers.

(Haas, col. 2, ll. 3-17.)
4. Haas discloses, however, that the presence of impurities in the final
product can be minimized using certain techniques:
The embodiment of the present invention in a fixed-bed
hydrogenation reactor equipped with a fixed-bed catalyst is
particularly suitable for the hydrogenation of
3-hydroxypropionaldehyde on an industrial scale and preferably
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for the hydrogenation of an HPA-containing aqueous reaction
mixture from the hydration of acrolein which has been freed
from unreacted acrolein. In a reactor such as this, the liquid
reaction mixture flows or trickles over the fixed-bed catalyst
together with the hydrogen introduced . . . .
The space velocity in the catalyst bed is adjusted in such
a way that a substantially quantitative HPA conversion is
obtained for a constant temperature throughout the catalyst bed,
for example 60° C. By dividing up the catalyst bed into the
temperature zones according to the present invention, the
residual carbonyl content in the pure 1,3-propanediol can be
reduced to values below 500 ppm and mostly below 100 ppm
for the same space velocity.

(Id. at col. 3, ll. 27-68.)
PRINCIPLES OF LAW
“In proceedings before the Patent and Trademark Office, the
Examiner bears the burden of establishing a prima facie case of obviousness
based upon the prior art.” In re Fritch, 972 F.2d 1260, 1265 (Fed. Cir.
1992).
In KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 415 (2007), the
Supreme Court emphasized “an expansive and flexible approach” to the
obviousness question, but also reaffirmed the importance of determining
“whether there was an apparent reason to combine the known elements in
the fashion claimed by the patent at issue.” Id. at 418 (emphasis added).
Ultimately, therefore, “[i]n determining whether obviousness is
established by combining the teachings of the prior art, the test is what the
combined teachings of the references would have suggested to those of
ordinary skill in the art.” In re GPAC Inc., 57 F.3d 1573, 1581 (Fed. Cir.
1995) (internal quotations omitted).

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ANALYSIS
We agree with Appellants that an ordinary artisan would not have
been prompted to apply Haas’ catalytic hydrogenation to a filtered,
anion/cation-exchanged, 1,3-propanediol-containing fermentation broth.
Specifically, rather than treating a composition that already contains
1,3-propanediol, Haas describes an improvement in the chemical synthesis
of 1,3-propanediol from a precursor compound by catalytic hydrogenation
(FF 3-4). Thus, Haas discloses that specific reaction parameters provide a
superior conversion rate of the precursor compound HPA to 1,3-propanediol,
resulting in less unconverted HPA in the final product, the unconverted
precursor being identified as an undesirable carbonyl impurity (id.).
We acknowledge the cited references’ teachings that 1,3-propanediol
can also be prepared by fermenting sugars or glycerol (FF 2). However,
because Haas discloses a process for efficiently converting the precursor
compound to 1,3-propanediol, rather than a process of treating an already-
produced 1,3-propanediol composition, an ordinary artisan would have
considered Haas’ method and the cited fermentation methods to be
alternative processes of preparing 1,3-propandiol (see FF 1-2).
Thus, because Haas’ chemical production of 1,3-propanediol would
have been viewed as an alternative to fermentation, we are not persuaded
that an ordinary artisan would have been prompted to include Haas’ catalytic
hydrogenation step in a method of purifying fermentatively produced
1,3-propanediol, particularly after the culture broth had already been filtered
and ion-exchanged, as recited in Appellants’ claims.
The Examiner urges that Haas would have implied to an ordinary
artisan that hydrogenation would have removed impurities from a
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1,3-propanediol-containing composition (Ans. 13). However, the Examiner
points to no disclosure in any of the cited references suggesting or implying
that a 1,3-propanediol-containing composition produced by fermentation
would have contained impurities in the form of unconverted precursor
compounds, particularly after that composition had been subjected to
filtration and cation and anion exchange procedures, as required in each of
independent claims 1 and 18-20.
Absent such a teaching, we are not persuaded that Haas would have
implied to an ordinary artisan that it would be desirable, or even useful, to
subject a filtered, ion-exchanged, 1,3-propanediol-containing fermentation
broth to catalytic hydrogenation. To the contrary, as discussed above, the
references of record suggest that fermentation and catalytic hydrogenation
were alternative methods of preparing 1,3-propanediol.
In sum, each of the appealed independent claims, claims 1 and 18-20,
requires the practitioner to filter a 1,3-propanediol-containing fermentation
broth, then subject it to anion and cation exchange procedures, and then
subject the ion-exchanged product to chemical reduction. For the reasons
discussed, we are not persuaded that the cited references would have
prompted an ordinary artisan to subject a filtered, ion-exchanged,
1,3-propanediol-containing fermentation broth to catalytic hydrogenation.
We therefore reverse the Examiner’s obviousness rejection of claims
1 and 18-20, and their dependent claims.

REVERSED

dm
Appeal 2010-007746
Application 10/839,188

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