Appeal No. 1996-2214
Application No. 08/208,123
We cannot agree with the examiner that the claimed ratios and ranges were the result of
routine experimentation, and in our judgment, any such experimentation would not have
come from within the teachings of the applied art.
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Takayama discloses a batch process for preparing citric acid in which glucose
levels as high as 150 g/L (as sugar) of invertase treated blackstrap molasses (Column 9,
line 38, Example 8) may be used. In the batch process of Takayama, the culturing step is
generally carried out under aerobic conditions (Column 4, lines 42-45).
The claimed continuous process of producing citric acid requires process steps of
“controlling the oxygen concentration to correspond to 15 to 30% of air oxygen saturation
of said medium;” of “obtaining a fermentation medium containing the carbon source in a
concentration corresponding to 200 to 400 g/l of glucose;” and “controlling
thecarbon/nitrogen ratio of the carbon source and the nitrogen source fed to said fermenter
to correspond to a molar ratio of 12 to 22 parts carbon source taken as glucose per part
nitrogen source, taken as NH .” The criticality of the oxygen saturation values to the
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claimed process, in particular, is reasonably established by the production data in Figure
4The examiner recognizes that Takayama discloses a batch process, not a
continuous process as claimed, and argues that conversion of a fermentation to a
continuous culture is notoriously old and well known in the art. Examiner’s Answer, second
numbered page 3. However,“P.E. Milsom,” Food Biotechnology Vol. I, p. 291 (1987),
which is cited in the specification at page 3, acknowledges art recognized difficulties in
conversion of a citric acid production process from a batch process to a continuous
process. This fact remains unaddressed by the examiner.
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