Mutant strain of Clostridium thermoaceticum useful for the preparation of acetic acid

DETAILED DESCRIPTION OF THE INVENTION The parent culture used for the development of the mutant strain of this invention was a wild type of C.
thermoaceticum, DSM 521.
The cultures used were obtained from the Massachusetts Institute of Technology, whose workers in turn had obtained it from Dr.
H.
G.
Wood, Case Western Reserve University, Cleveland, Ohio.
Growth was monitored by measuring the absorbance at 540 nm.
A Spectronic 20 spectrophotometer (Bausch & Lomb, Inc.
, Rochester, N.
Y.
) was used for the measurements.
The sample was diluted with distilled water to read between 0.
1 and 0.
7 absorbance and the measurements were made in matched Hungate tubes of 16 mm outside diameter against a distilled water blank.
Two or three grains of sodium dithionite were added to the diluted sample prior to reading when resazurin indicator was used to maintain it in its colorless state.
Acetic acid and glucose concentrations were determined using high-performance liquid chromatography (HPLC).
A sample of fermentation mixture was centrifuged at about 10,000.
times.
g for 10 minutes to pellet the cells.
Components of the supernatant were chromatographed by elution with 0.
06 N H.
sub.
2 SO.
sub.
4 from a cation-exchange resin in the hydrogen form.
The eluted components were detected by means of a differential refractometer, plotted on a recorder and quantitated using an electronic integrator.
The area underneath the curve which represents concentration of each component was reported as a percentage of the total area.
The general procedure is that given in "Analyses of Carbohydrate Mixtures by Liquid Chromatography", Am.
Soc.
Brew.
Chem.
Proc.
, 1973, pp.
43-46.
The separations were made on a 1-foot HPX-87 column in the hydrogen form, available from Bio-Rad Laboratories, Richmond, Calif.
In the description of this invention, the words "dilution rate", as used in this application, have the dimensions of per hour (hr.
sup.
-1).
This rate is obtained by dividing the flow rate of the medium in volume units per hour by the operating volume of the reactor