Patent GB-424135-A (GB)
Title: Production of organic compounds by fermentation
IPC: C12P7/28
Filed: 1933-08-15
Abstract: Organic compounds produced by fermentation such as ethyl alcohol, or butyl alcohol and acetone, are removed in liquid form during the fermentation by means of a solvent.  Suitable solvents are preferably aliphatic compounds such as isoamyl and higher alcohols, esters such as amyl and butyl acetates and ethyl butyrate, isopropyl and higher ethers, diethyl and other water-insoluble ketones, and petroleum ether, but aromatic compounds such as benzene may also be used.  The fermentation product may be removed continuously or intermittently, and suitable additions of starting materials, ferments or bacteria, &c. may be made to maintain the composition of the mixture constant. In fermenting with a top yeast, the enzyme effecting the change may be added, whereas with a bottom yeast it is preferred to add a co-enzyme.  When producing alcohols, soluble phosphates may be added, preferably together with a body such as sodium arsenate which prolongs the increased activity due to the addition of phosphate. When more than one product of fermentation is being produced it is not necessary that the products should be removed in the proportion in which they are produced.  The process is particularly suitable for anaerobic processes such as the alcoholic and butyl-acetonic fermentations, in which a layer of solvent is maintained on the surface of the liquor; by providing a run-off so that a constant level is maintained, and supplying the solvent continuously, a continuous removal of the product is effected.  In an example, a solution of sugar which may be produced from cellulose, is sterilized, and a suitable yeast culture and suitable nutrients are introduced, a layer of isoamyl alcohol being maintained on the surface with continuous supply and run-off; the isoamyl alcohol is supplied continuously at the bottom of the fermentation vessel and withdrawn at the top, and fresh sugar solution is supplied so as to keep the sugar concentration constant.ALSO:Ethyl and butyl alcohols and other products of fermentations are removed in liquid form during the fermentation by means of a solvent.  Suitable solvents are preferably aliphatic compounds such as isoamyl and higher alcohols esters such as amyl and butyl acetates and, ethyl butyrate, isopropyl and higher ethers, diethyl and other water-insoluble ketones, and petroleum ether, but aromatic compounds such as benzene may also be used.  The fermentation product may be removed continuously or intermittently and suitable additions of starting materials, ferments or bacteria &c. may be made to maintain the composition of the mixture constant.  In fermenting with a top yeast, the enzyme effecting the change may be added, whereas with a bottom yeast it is preferred to add a co-enzyme.  When producing alcohols, soluble phosphates may be added, preferably together with a body such as sodium arsenate which prolongs the increased activity due to the addition of phosphate.  When more than one product of fermentation is being produced, it is not necessary that the products should be removed in the proportion in which they are produced.  The process is particularly suitable for anaerobic processes such as the alcoholic and butyl-acetonic fermentations, in which a layer of solvent is maintained on the surface of the liquor; by providing a run-off, so that a constant level is maintained, and supplying the solvent continuously, a continuous removal of the product is effected.  In an example, a solution of sugar, which may be produced from cellulose, is sterilized, and a suitable yeast culture and suitable nutrients are introduced, a layer of isoamyl alcohol being maintained on the surface, with continuous supply and run-off; the isoamyl alcohol is supplied continuously at the bottom of the fermentation vessel and withdrawn at the top, and fresh sugar solution is supplied so as to keep the sugar concentration constant.