Continuous production of ethanol by use of flocculent zymomonas mobilis

DETAILED DESCRIPTION OF PREFERRED APPARATUS AND PROCESS EMBODIMENTS OF THE INVENTION The effectiveness of strains of Zymomonas mobilis for converting sugar to ethanol has been previously reported by P.
J.
Rogers et al in an article entitled "High Productivity Ethanol Fermentations with Zymomonas Mobilis", published in the August/September 1980 issue of Process Biochemistry.
Researchers at the Oak Ridge National Laboratories in Oak Ridge, Tenn.
, including the inventors named in this application, have been engaged in developmental programs directed toward determining effective means for immobilizing biological catalysts on or in packings for continuous-flow apparatus for producing ethanol by fermentation.
In connection with these investigations, a strain of Z.
mobilis identified as ATCC No.
10988 was obtained from the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md.
, during the month of July, 1980.
Subsequently various materials were tested by the applicants to determine their efficacy in immobilizing cultures of the above-identifed strain of Z.
mobilis.
Furthermore, during approximately 14 fermentation tests conducted with cultures of the ATCC No.
10988 Z.
mobilis, applicants observed no tendency of the microorganism to flocculate.
However, after this period of experimentation with ATCC No.
10988 cultures under various fermentation conditions, the applicants observed during one test (which will be described in detail hereinafter) that macroscopic floc particles of one Z.
mobilis culture were spontaneously formed in a continuously flowing aqueous stream containing sugar and other nutrients.
This particular Z.
mobilis strain has been isolated and maintained by means of conventional techniques which are well known by microbiologists, and a sample of the strain is deposited in the Agricultural Research Culture Collection, International Depository Authority (NRRL), 1815 N.
University Street, Peoria, Ill.
, and registered therein as Zymomonas mobilis "f", International Depository Authority accession number NRRL B-12526