Methanol foam fermentation to single cell protein by Pseudomonas methanica

Abstract

A process for the production of microbial cells by fermenting a carbonaceous material in a foam fermenter containing an oxygen-enriched nutrient medium. The process uses a source of carbon which is assimilable by the microorganism for the production of the microbial cells. The microbial cells are separated and removed from the foam fermenter for use as a food product high in protein content. .Iadd.

We claim: .[.1. A process for the production of microbial cells, said process including the steps of: 
     
       a. said alcohol has from 1-6 carbon atoms..]. .[.3.  The process as set forth in claim 1 wherein: a. said alcohol is methanol..]. .[.4. The process as set forth in claim 3 wherein:   a. said microorganism is Pseudomonas methanica..]. .[.5. The process as set forth in claim 4 wherein:   a. said microorganism is Pseudomonas methanica NRRL B3449..]. .[.6. The process as set forth in claim 3 wherein:   a. said methanol is present in the fermenter in the range of approximately 0.001 to 5% by volume of the contents..]. .[.7. The process as set forth in claim 6 wherein:   a. said methanol is introduced at a rate wherein a minimum of methanol is discharged from the fermenter with effluent normally discharged from the fermenter..]. .[.8. The process as set forth in claim 3 wherein:   a. said microorganism is Hansenula polymorpha..]. .[.9. The process as set forth in claim 3 wherein:   a. said fermenter is maintained during operation at a pressure above 1 atmosphere..]. .[.10. The process as set forth in claim 3 wherein:   a. said fermenter is operated at a temperature between approximately 30° to 65° C..]. .[.11. The process as set forth in claim 3 wherein:   a. said process is continuous wherein oxygen and said nutrient and methanol are continuously introduced into said fermenter at controlled rates..]. .[.12. A process for the production of microbial cells, said process including the steps of:   a. placing a microorganism in a fermenter, said microorganism being capable of assimilating a straight chain alcohol having 1 to 16 carbon atoms per molecule as a main source of carbon;   b. continuously introducing a nutrient medium into said fermenter at a controlled rate;   c. introducing oxygen into said fermenter continuously at a controlled rate for aerobically fermenting said alcohol;   d. continuously introducing said alcohol into said fermenter at a controlled rate for said microorganism to assimilate as the carbon source and produce microbial cells;   e. maintaining said fermenter during operation at a pressure of at least approximately 1 atmosphere;   f. maintaining said alcohol and medium in a foamed condition in said fermenter so that said fermenter is essentially foam-filled; and   g. continuously separating and recovering the microbial cells produced in said fermenter..]. .[.13. The process as set forth in claim 12 wherein:   a. said microorganism is Pseudomonas methanica..]. .[.14. The process as set forth in claim 13 wherein:   a. said alcohol is present in the fermenter in the range of approximately 0.001 to 5% by volume of the contents;   b. maintaining said fermenter at an operating temperature of approximately 30° to 65° C..]. .[.15. The process set forth in claim 12 wherein:   a. said microorganism is Hansenula polymorpha..]. .[.16. The process as set forth in claim 12 wherein:   a. said alcohol is methanol..]. .Iadd. 17. A process for production of microbial cells in a fermentation vessel having a draft tube positioned therein with a first flow path portion through said draft tube and a second flow portion between the draft tube and a portion of the vessel, said process including the steps of:   (a) placing a microorganism into a fermenter vessel containing an aqueous nutrient medium and aerobically culturing said microorganism, said microorganism being capable of assimilating alcohol as a main source of carbon;   (b) introducing oxygen into the fermenter;   (c) introducing at least one alcohol selected from the group consisting of methanol and ethanol into the fermenter vessel as the main carbon source for said microorganism to assimilate and produce microbial cells;   (d) maintaining said alcohol and medium in a foamed condition in said fermenter vessel so that said fermenter vessel is essentially foam-filled;   (e) continuously circulating the foamed alcohol and medium through the first flow path portion to the second flow path portion and then back to the first flow path portion within the fermenter in loop flow; and   (f) separating and recovering the microbial cells produced in said fermenter vessel;   
     
     
       wherein said microorganism is Pseudomonas methanica. .Iaddend. .Iadd. 18. The process as set forth in claim 17 wherein: a. said microorganism is Pseudomonas methanica NRRL B3449. .Iaddend.