l ' 2,413,698 a stares PATENT OFFICE 2,413,698 PROCESS FOR THE RECOVERY OF UNFER; MENTED AND UNFERMENTABLE SUGARS FROM SACCHARIFIED TIONS STARCH SOLU- ' Eduard Farber, New-Haven, Conn., and James S. ' Wallerstein, New York, N. Y., assignors to The Overly Biochemical Research Foundation, Inc., New York, N. Y., a corporation of‘ New York No Drawing. Application July 30, 1943, Serial No. 496,834 16 Claims. (Cl. 195-38) - 1 2 or hydroxide is conducted after the fermentation This invention relates to the separation and of the sacchari?ed starchy material, ‘the fer recovery of unfermented and likewise of unfer merited liquor is preferably ?rst ?ltered to re mentable sugars from sacchari?ed starch solu move the yeast which may then be re-used for tions, and more particularly, to the separation of fermenting other batches. maltose and other polyoses from solutions of We have found that when an alkaline earth" sacchari?ed starchy materials. oxide, for example, calcium or strontium oxide, It is the general object of the invention to in finely ground form, is added to solutions con effect efficient removal of maltose and other taining maltose and other polyoses at relatively polyoses which either are entirely unfermentable low temperatures (0° to 40° C.) a precipitate is or remain unfermented during the particular 10 formed which contains the polyoses in com conditions of fermentation, for example, alkaline bination with the alkaline earth oxide. The fermentation, to which a sacchari?ed starchy precipitate settles out after a period of standing, material is subjected. and may be readily removed from the mother It is also an object of the invention to provide liquor by ?ltration, centrifugation, or often by 15 a process for the preliminary purification of sac simple decantation, preferably at low tempera chari?ed starchy materials prior to subjecting tures“. The temperature is not critical within the such materials to a fermentation during which specified limits; near the lower limit, formation the separated sugars are either not converted or are converted only partially, whereby a fer of the compound may be slow and filtration dif ?cult; near the upper limit, it is necessary to merited mash is obtained, in which the content‘ 20 carry out the precipitation quickly, otherwise of unfermented sugar is greatly reduced over dark colored decomposition products are formed. prior procedures, so that the recovery of the con These occur if the temperature is permitted to versionproducts, and particularly of glycerol, is rise substantially beyond the upper limit cited. greatly facilitated. The alkaline earth must be thoroughly ad 25 It is a further object of the invention to effect mixed with the solution for a complete reaction. I puri?cation of the fermented liquor obtained by An e?icient way of~carrying this out consists in the alkaline fermentation of sacchari?ed starchy treating the mixture in a ball mill or similar materials, by removal of a large part, if not all, mechanical mixing device. Subsequently, the of the unfermented sugar content of the liquor, 30 maltose and other polyoses may be recovered so as thereby to facilitate and improve the re from the precipitate by treatment of the com covery of the products of the fermentation from ’ pound with acids which form insoluble or spar the liquor. ingly soluble salts with. the alkaline earth metals, Other objects and‘ advantages of the invention the effect here being to convert the alkaline earth will become clear as the more detailed descrip oxides into salts and to bring the polyoses into tion thereof proceeds, and the features of novelty 35 solution. It is particularly advantageous to will be set forth in the appended claims. . In accordance with the present invention, a sacchari?ed starchy material is subjected, either form a salt which is but sparingly soluble in order that the solution of the polyoses may be reason ably pure for subsequent uses. Thus, for ex before or after fermentation, to the action of an ample, maltose may be precipitated with lime oxide or hydroxide of an alkaline earth metal, 40 and then redissolved by means of sulfuric acid, and especially of calcium or strontium, whereby maltose and other polyoses are precipitated in the form of their more or less insoluble combina tions with the alkaline earth metal oxide or hy droxide; whereafter the precipitated material may be decomposed by means of an acid, prefer ably one which forms an insoluble or sparingly soluble compound with the alkaline earth metal, and the maltose and other polyoses so liberated forming the sparingly soluble calcium sulfate, and leaving a fairly pure sugar solution. Gaseous acid anhydrides which form insoluble or spar 45 ingly soluble alkaline earth metal compounds, are also effective agents; thus carbon dioxide may be added down to pH 6.0, the insoluble carbonates thus formed being readily removed. Sulphur dioxide may be similarly} employed. The process is of particular advantage where may then be acid-hydrolyzed to convert them to 50 the sacchari?ed solution of starchy materials is glucose or other fermentable sugars. This hy employed for the production of glycerol by an drolyzed sugar solution may then be combined alkaline fermentation. Under these conditions, With/‘8. new batch of sacchari?ed starchy mate the glucose is fermented whereas the maltose rial and subjected to fermentation. Where the ferments at best very slowly. Any residual un treatment with the alkaline earth metal oxide 55 2,413,698 3 ' 4 fermented sugar (consisting mainly of maltose) tion with reference to the unfermentable sugars remaining in the mash will tend to interfere present. The materials are mixed in a ball mill, with the subsequent distillation of the glycerol and the mixture permitted to stand at room tem from the concentrated slops. Unfermented sugperature of about 25° C. A yellowish brown pre ars under these conditions tend to form dark 5 cipitate is formed containing disaccharides and colored and caramel-like compounds which en~ polysaccharides not converted to glucose, in com trap the glycerol formed by the fermentation and prevent its ready volatilization by means of steam. By the use of lime or other alkaline fermentable under alkaline conditions into in- bin-ation with the lime. For complete precipita tion, the solution is cooled to about 5°’ C. over night. This precipitate is removed by ?ltration. taken place. ‘ _ ‘ soluble compounds with alkaline earth oxides oi Meanwhile, the sugar-lime precipitate formed hydroxides‘ is treated with dilute sulfuric acid the insoluble The recovered maltose may be used as such or calcium sulfate formed ?ltered on’, the sugar be_ for alcoholic fermentation under non-alkaline 2n ing thereby redissolved._and the acidity is amidst a mineral acid like sulfuric, and then fermented eral hours at temperatures near the boiling point. to glycerol under alkaline conditions. the disaccharides and polysaccharides will be By the removal of the unfermented di- and 25 converted substantially to glucose which, if de polysaccharides, either before or‘ after an alkasired after partial or complete neutralization, line glycerol fermentation, lighter colored slops are obtained, improved yields of glycerol are se- may be added toasubsequent mash. Eiwmllle 2-—IAt the end of an alkaline glycerol After the addition of the alkaline earth metal lyzed as in Example 1. The solution remaining oxide in the speci?ed amount, the mixture will after removing the strontium oxide-unfermented show a high alkalinity. Byv reducing this alkg, 40 sugar compound from the fermented mash is con tially above pH 8.0, but still in the alkaline range, _acid to a pH value of about 4 and steam-distilled a considerable increase in insoluble carbohydrate under reduced pressure- Thereby the glycerol is compound is obtained. This may be due to the more readily recovered than without the previous mutual in?uences on solubility of excess alka- 45 removal of the unfermented sugar, line earth metal oxides and dissolved polymeric Example 3-—A slakedlime slurry is added to the carbohydrate. \ ~ fermented mash of 9. glycerol fermentation. The This adjustment of the pH can be carried out solution contains 2% alcohol and about 4% un by using carbon dioxide gas in such amounts'that fermented carbohydrate sugars as well as 3% the alkalinity is lowered to a pH range between 50 glycerine. 40 grams of the slaked lime per liter 7.5 and 8.0. are added slowly with stirring at a temperature This additional re oval of carbohydrate from of 25° C. When the stirring is discontinued after _ glycerine is to be recovered. A further advan- 55 added to the solution with stirring, and the pH is tage achieved by this method in the case of ferthereby reduced from about 11 5 to 8 0. The solu mentation mashes consists in producing solutions tion ls then ?ltered and about 60% of the unfer which on concentrating remain clear and do not merited carbohydrate is removed from the solu deposit large amounts of insoluble matter tion The precipitate is acid hydrolyzed with sul In recovering sugar from a fermented mash by 60 furic acid at pH 0 to 1 and added to a subse vantageous to precipitate the unfermented sugar The fermented mash from which the precipitate prior to recovery of the alcohol contained in the 65 is removed is concentrated and subjected to a fermentation liquor. steam distillation for the recovery of glycerol Example 1.—A wheat mash is used for the pro- The mash to be fermented may be obtained by means of dilute mineral acids, as, for example, 70 sulfuiic acid Subsequently the acidity is neutralized by means of lime, forming calcium sulfate, which is separated. Thereafter ?nely We claim 1. The method of'separating maltose from solu~ tions of sacchari?ed starchy materials containing the same, compiising adding to such a solution 5 metal oxides and hydroxides at temperatures of — 2,413,698 6 ing the same, comprising fermenting a solution of about 0°-40° C. and in quantity suf?cient to pre cipitate at least a substantial part of the maltose, mixing the materials and allowing them to stand until the compound of the metal base with the maltose begins to settle, removing the insoluble compound from the solution, and decomposing the compound by means of a member of the group consisting of acids and acid anhydrides which form sparingly soluble salts with the alkaline earth metal. ‘ 2. The method according to claim 1, in which the pH after precipitating the compound of mal tose with the alkaline earth base is adjusted to between about 7.5 and 8.0 before separating the insoluble compound from the solution. 7 . sacchari?ed starchy material for the production of glycerol, adding to the fermented solution a member of the group consisting of alkaline earth metal oxides and hydroxides at a temperature no 1 higher than about 40° C. and in quantity sufficient to precipitate at least a substantial part of the maltose, mixing the materials and allowing them to stand until the compound of the metal base with the maltose begins to settle, removing the 10 insoluble compound from the solution, and de composing the compound by means of a member of the group consisting of acids and acid anhy drides which form sparingly soluble salts with the earth metal. _ 15 alkaline 12. Process according to claim 11, wherein the 3. The method according to‘claim 1, wherein adding of the alkaline earth metal base is made after the precipitation of the compound of the ' in the presence of the alcohol formed during the alkaline earth metal base and the maltose the fermentation. pH value is adjusted to between about 7.5 and 8.0 13. The method for the manufacture of glyc with carbon dioxide gas before separating the in 20 erol which comprises adding to a, maltose-con taining solution of sacchari?ed starchy materials soluble compound from the solutio . 4. The method according to clalm 1, in which a member of the group consisting of alkaline earth metal oxides and hydroxides at temperatures no the precipitation of the maltose is carried out in higher than about 40° C. and in quantity sufficient the'presence of alcohol. 5. The method of separating maltose from so to precipitate at least a substantial part of the maltose, separating the precipitate of the metal lutions of sacchari?ed starchy materials contain ing the same, comprising adding to such a solu base with the maltose, subjecting the residual tion a member of the group consisting of alkaline sugar solution to fermentation under alkaline and hydroxides in quantity suf conditions, and subsequently distilling glycerol " earth metal oxides ?cient to precipitate at least a substantial part 30 from the fermented solution. of the maltose, intimately mixing the materials 14. The method for the manufacture of glyc erol which comprises fermenting a solution of to promote reaction, separating the sugar pre cipitate from the solution, and subsequently de saccharl?ed starchy material under alkaline con composing the precipitate to liberate the soluble ditions and, prior to distillation of the formed sugars. 6. Method according to claim 5, wherein the decomposition is effected with the aid of a mem~ ber of the group consisting of acids and acid glycerol, treating the solution with a metal‘ base of the group consisting of alkaline earth metal oxides and hydroxides at a temperature no higher than about 40° C. and in quantity sufficient to precipitate‘ at least a substantia1 part of the maltose, and separating the precipitate of the anhydrides which form sparingly soluble salts with the alkaline earth metal. '7. Method according to claim 5, wherein the ’ metal base with the maltose. 15.‘ The method according to claim 14, wherein alkaline earth metal compound is calcium oxide. 8. Method according to claim 5, wherein the the treatment with the alkaline earth metal base alkaline earth metal compound is strontium oxide.‘ takes place after the fermentation and in the 9. Method according to claim 5, wherein the 45 presence _of the formed alcohol. ’ 16. The method according to claim 14, wherein alkaline earth metal compound is calcium hy the treatment with the alkaline earth metal base droxide. ~ ' 10. Method according to claim 5, wherein the takes place at approximately room temperature. decomposition of the precipitate is effected with 50 dilute sulfuric acid. 11. The method of separating maltose from so lutions of saccharifled starchy materials contain-l EDUARD BARBER. JAMES s. WALLERSTEIN.