CS259615B1 - Method of molasses or waste fermented mash containing solutions' cleaning and liquidation - Google Patents

Abstract

Method for cleaning and disposing of solutions containing molasses or waste yeast, optionally a distilled fermented mash with the aid of ammonium ions in the form of hydroxide, phosphate or carbonate as effective clarifier and at the same time most easily and preferably assimilable N-source for yeast cell. This is possible eliminate unwanted and refinable refinements thiolalcohols in spirit fermentation in the metabolism of sulfur amino acids yeast if it is done advantageous in terms of liquidation and water savings recycling of treated waste mists in the next fermentation process of alcohol production.

Description

Process for purifying and disposing of solutions containing molasses or waste yeast or distillery fermented mash by means of ammonium ions in the form of hydroxide, phosphate or carbonate as the active clarifying agent and at the same time the most easily and preferably assimilable N-source for the yeast cell. In this way, it is possible to eliminate the formation of undesirable and refining non-removable thioalcohols in alcoholic fermentation during the metabolism of sulfur amino acids by yeasts, provided that advantageous recycling of the treated waste mashes is carried out in another fermentation process of alcohol production.

, 259615

The present invention relates to a method for purifying molasses solutions or waste yeast or distillery fermented by clarification using ammonium ions in the form of hydroxide, phosphate or carbonate as the active clarifier at a solution pH of greater than 7.0. In this manner, the yeast preferably assimilated N-source is simultaneously fed into a medium lean in easily assimilable nitrogen.

According to AO 251 017, the above solutions are cleaned of contaminating microorganisms, fermentation inhibitors and an organic-niineral complex causing technological process incrustation by cold chemical clarification with oxalic acid, alkali metal or earth hydroxides, carbon dioxide, carbonate, phosphoric acid or quaternary ammonium The clarified, de-sludged solutions are recycled in a new fermentation process or concentrated. Recycling of treated waste mashes, especially yeast yarns, in the new distillery fermentation cycle is very beneficial not only for the possibility of partial replacement of clean process water, but also for the capture and utilization of the majority of organic pollution in thickened distillers. However, a certain disadvantage of recycling fermented waste mashes in a new cycle of alcoholic fermentation is the possibility of occurring trace amounts of thioalcohols produced by yeast during the metabolism of sulfur-containing amino acids. Since sensory undesirable admixtures of thioalcohols are not removed during normal refining, it is necessary to prevent their formation by adjusting the fermentation conditions.

The disadvantage of recycled waste mash is eliminated by the method of purifying and disposing of molasses or fermented mash waste according to the invention which consists in using ammonium ions in the form of ammonium hydroxide, ammonia water, phosphate or ammonium carbonate as effective clarifiers of waste mash wherein the precipitation takes place at a pH greater than 7.0 and after removal of the organic-mineral sludge and the pH of the clarified solution to a value optimal for fermentation (4.0 to 5.0) the balance of the dissociated ammonium salts is assimilated by yeast as a preferentially usable nitrogen source. it is also known to stimulate alcoholic fermentation.

Higher technical effect of the process according to the invention lies in the coagulation and clarifying effect of ammonium ions (removes 10 to 20 wt.% Of the content of organic substances expressed as chemical oxygen demand value (CODcl) and eliminates at least 70 wt.% Of CaO 3. of sulfur-containing amino acids, due to the large excess of free ammonium ions that bleed the need for easily assimilated nitrogen.

One of the advantages of the process according to the invention is the use of diammonium phosphate for clarification and at the same time for stimulating the subsequent fermentation process with ammonia ions as well as phosphate.

In the following, the method of the invention is illustrated in the examples without being limited thereto.

Example 1

Up to 3 1 waste yeast mash with pH

5.8, with stirring, 5.4 ml of ammonia water with a NIT3 content of 25 wt. After stabilizing the pH at 8.2 followed by addition of 9.0 g solid (NH3) HCl. The pH dropped to about 10 minutes after dissolution.

6.9 and was therefore re-adjusted with

3.6 ml of ammonia water to a final pH of 7,6. After 60 minutes of sedimentation, the calcium content (49 ppm) in the clear solution was analyzed by the AAS method (air - C2H2, λ 422.1 mm; I = 5 mA; gap 0.5 millimeter; ionization attenuation 0.1% [m / V) Kel).

The original Ca content in the untreated mash was 182 ppm. The clarified mash was further used for recycling in an alcoholic fermentation laboratory test, maintaining the dilution water replacement ratio as calculated by the fermentation vat template (12,000 l treated mash = 50% dilution water in the sample at the start of fermentation).

After 20 hours of fermentation at 30 ^° C, the weight loss due to CO 2 evolution was 91 percent of that found in the control (H2OJ and the pycnometrically determined ethanol content was 7.86 vol% versus 7.74 vol% found in the control samples. in both cases it corresponds to the stationary conditions of laboratory fermentation without molasses inflow.

Example 1 a d 2

In 3 l waste yeast mash clarification was performed with the precipitation of the organic-mineral complex by the addition of 26.4 ml of a 20% Na2CO3 solution, increasing the pH from 5.8 to 8.0 and forming fine sludge flakes, maintained slightly elevated stirring. After the addition of 9.0 g of solid (NH 2 OH 2 CH 3), the mixture was further stirred for about 15 minutes, during which time the pH dropped to 7.1 and was therefore adjusted by further addition.

20.6 ml of 20% carbonate solution to a final pH of 7.6. After the stirrer stopped, the precipitated sludge was rapidly sedimented.

As in Example 1, the residual Ca content (55.11 ppm) was determined in the clear solution. The Ca concentration in the original mash was 248 ppm. The clarification-treated mash was then used in the laboratory fermentation test for the possibility of recycling with dilution water replacement as in Example 1.

The degree of fermentation reached (88.0 ° / o) controls without mash and the pycnometric ethanol content after alcoholic fermentation ranged from 80.5 to 104.4% / ethanol for controls where the sample volume was set just water.

In order to determine the sensory values of refined ethanol after fermentation tests using treated (see Examples 1 and 2) and untreated yeast waste mash in alcoholic fermentation, ethanol was separated from larger samples with fermented molasses by simple distillation and ethanol distillate was fractionally refined using laboratory packed columns containing about 38 theoretical plates.

About 20 x 10 mL fractions from each sample were collected from the top of the column at a set deflegmation ratio of 5 to 7: 1 gradually as the boiling point increased.

Samples of intermediate fractions of refined ethanol fermentation experiments with untreated waste mash showed an unpleasant odor, the other test and control samples did not differ significantly sensory from each other.

Claims (1)

Process for purifying and disposing of solutions containing molasses or waste fermented waste, characterized in that clarification is carried out at a pH higher than 7.0 by addition of ammonium ions in the form of 0.02 to 0.5% w / w. ammonium BACKGROUND OF THE INVENTION, especially ammonium hydroxide, ammonia water, ammonium phosphate or ammonium carbonate, and the resulting sediment is separated from the clarified solution.