Appeal No. 1996-2214
Application No. 08/208,123
Claim 21 is illustrative of the claims on appeal and reads as follows:
21. A process for the continuous production of citrate or citric acid, comprising
the steps of:
(a) continuously feeding to a fermenter containing a yeast of the genus
Candida capable of transforming glucose to citric acid by fermentation and a nutrient
medium, oxygen, a carbon source selected from the group consisting of glucose,
saccharose, molasses and hydrolysates of starch which are convertible by candida strains
to citric acid , and at least one ammonium compound as a nitrogen source, to obtain a
fermentation medium containing the carbon source in a concentration corresponding to
200 to 400 g/l of glucose;
(b) fermenting the carbon source in the fermentation medium to citric acid in
said fermenter at a temperature of about 29 to 31°C, a pH of 4 to 5.5 and for a mean
residence time of 60 to 120 hours, while controlling the carbon/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 , and
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controlling an oxygen concentration in said fermenter to corresponding to 15 to 30% of air
[1]
oxygen saturation of said medium ;
(c) continuously withdrawing fermentation product from said fermenter; and
(d) recovering citrate or citric acid from said fermentation product.
The prior art reference of record relied upon by the examiner in rejecting the
appealed claims is
Takayama et al (Takayama) 4,322,498 Mar. 30, 1982
1This step is interpreted to mean controlling the amount of oxygen contained in the
fermentation medium as a percentage of the total amount of oxygen which could be held by
said fermentation medium. See Paper No. 7, page 4, filed May 19, 1995.
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