DETAILED DESCRIPTION OF THE INVENTION The process of the present invention involves incubating 2-keto-L-gulonic acid or 2-keto-D-gluconic acid, each as the free acid, or as its sodium, potassium, or calcium salt, and cells of a thermoacidophilic microorganism capable of producing and/or enhancing the production of L-ascorbic acid, or its sodium, potassium, or calcium salt, from 2-keto-L-gulonic acid, or its sodium, potassium, or calcium salt, or D-erythorbic acid, or its sodium, potassium, or calcium salt, from 2-keto-D-gluconic acid, or its sodium, potassium or calcium salt, at a high temperature (i.
e.
at temperatures from about 30.
degree.
C.
to about 100.
degree.
C.
) and at an acidic pH (i.
e.
at a pH from about 1 to about 6), in a solution as shown in Example 2, hereinafter, and isolating the L-ascorbic acid, or its sodium, potassium, or calcium salt, or D-erythorbic acid, or its sodium, potassium, or calcium salt, from the solution.
As used herein, "or its sodium, potassium or calcium salt" or an equivalent expression as applied to "2-keto-L-gulonic acid", "2-keto-D-gluconic acid", "L-ascorbic acid", or "D-erythorbic acid" will be referred to hereinafter as "or its salt".
Moreover, any given concentrations of these acids or their salt forms will be expressed as being based on the free acid form even though a salt form may be present, unless clearly stated for the particular acid, or the respective salt form that is present.
As used herein, a "thermophilic microorganism" is a microorganism with optimal growth at a temperature above about 55.
degree.
C.
As used herein, an "acidophilic microorganism" is a microorganism with optimal growth at a pH in the acidic range, preferably below about pH 6, and no growth at a pH in the neutral range (i.
e.
, in the pH range from about 6 to about 8).
Thus, a "thermoacidophilic microorganism" is a microorganism with both of these properties, i.
e.
, optimal growth at a temperature above about 55.
degree.
C.
, and at a pH below about 6, and no growth in the pH range from about 6 to about 8
|
Molecular Biology 
