Method for preparing citric acid by fermentation

A technology of citric acid and fermentation strains, applied in the direction of microorganism-based methods, fermentation, biochemical equipment and methods, etc., can solve the problems of unfavorable synthesis and action of glucoamylase, unfavorable growth of Aspergillus niger strains, high DE value of fermentation medium, etc. , to achieve the effect of improving the conversion rate of sugar and acid, avoiding adverse effects, and reducing the amount of residual sugar

Active Publication Date: 2012-07-04
COFCO BIOTECHNOLOGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method owing to be to add glucoamylase before inoculation, although ambient temperature is conducive to saccharification, the DE value of fermentation medium is too high when inserting Aspergillus niger strain, is unfavorable for the synthesis and the effect of self glucoamylase of Aspergillus niger strain, does not It is beneficial to the growth of Aspergillus niger strains; the amount of glucoamylase is relatively large, and the cost is high; the residual sugar in the fermentation broth is relatively high

Method used

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  • Method for preparing citric acid by fermentation

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Effect test

Embodiment 1

[0058] This example is used to illustrate the method for preparing citric acid by fermentation provided by the present invention.

[0059] (1) 56 kilograms of harvested corn were moistened and stewed in a hot water tank until the water content of the corn was 15% by weight, and then pulverized to obtain a pulverized product with an average particle diameter of 400 microns.

[0060] (2) The pulverized product is slurried at a concentration of 25% by weight. For every gram of the pulverized product, 20 enzyme activity units of amylase (Novozymes, α-amylase, an embodiment of the invention) are added. and the comparative example are all the amylase), enter the ejector, and enzymolyze for 100 minutes under the conditions of 85° C. and pH 5.5, to obtain the enzymolysis product.

[0061] (3) The enzymolysis product is filtered by a hydraulic plate and frame filter press to separate the enzymolysis liquefaction liquid and the enzymolysis filter residue, wherein the water content of th...

Embodiment 2

[0066] This example is used to illustrate the method for preparing citric acid by fermentation provided by the present invention.

[0067] (1) 56 kg of harvested corn was moistened and stewed in a hot water tank until the water content of the corn was 20% by weight, and then pulverized to obtain a pulverized product with an average particle diameter of 800 microns.

[0068] (2) The pulverized product is slurried at a concentration of 25% by weight. For every gram of the pulverized product, 50 enzyme activity units of amylase are added, and the product enters the ejector, and the product is 5.7 at 95°C and the pH is 5.7. Enzymolysis was carried out for 110 minutes to obtain an enzymolysis product.

[0069] (3) The enzymolysis product is filtered by a hydraulic plate and frame filter press to separate the enzymolysis liquefaction liquid and the enzymolysis filter residue, wherein the water content of the enzymolysis residue is 40% by weight.

[0070] (4) Prepare a fermentation ...

Embodiment 3

[0074] This example is used to illustrate the method for preparing citric acid by fermentation provided by the present invention.

[0075] (1) 56 kilograms of harvested corn were moistened and stewed in a hot water tank until the water content of the corn was 10% by weight, and then pulverized to obtain a pulverized product with an average particle diameter of 500 microns.

[0076] (2) The pulverized product is slurried at a concentration of 25% by weight. For every gram of the pulverized product, 15 enzyme activity units of amylase are added, and the product enters the ejector, and the mixture is placed under the conditions of 80° C. and pH 5.4. Enzymolysis was carried out for 120 minutes to obtain an enzymolysis product.

[0077](3) Press-filter the enzymolysis product with a hydraulic plate and frame filter press to separate the enzymolysis liquefaction liquid and enzymolysis filter residue, wherein the water content of the enzymolysis residue is 70% by weight.

[0078] (4...

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Abstract

The invention discloses a method for preparing citric acid by fermentation, which comprises the following steps: under the conditions of generating citric acid, inoculating citric acid fermentation strain into fermentation media, and carrying out fermentation, thereby obtaining the fermentation liquid. The invention is characterized in that the method also comprises the step of adding saccharifying enzyme into the fermentation media 0-8 hours after inoculating the citric acid fermentation strain. The method disclosed by the invention enhances the saccharifying capacity in the fermentation process, solves the contradiction between the pH value requirements from citric acid synthesis and saccharification in the fermentation process, and avoids the adverse effect of high DE (dextrose equivalent) value on Aspergillus niger, so that the sugar solution in the fermentation media is saccharified more thoroughly, thereby lowering the residual sugar amount in the fermentation liquid, enhancing the end citric acid content and single-tank acid supply amount, increasing the conversion rate of sugar acid and shortening the fermentation period.

Description

technical field [0001] The invention relates to a method for fermenting and preparing citric acid. Background technique [0002] The fermentation process of the traditional citric acid fermentation industry includes: pretreatment of starchy raw materials, enzymatic hydrolysis of starchy raw materials into dextrin sugar solution, whose DE value is about 25, and preparation of fermentation medium; inserting Aspergillus niger spores into the seed medium After the culture is mature, it is transferred to the fermentation medium for fermentation to produce citric acid. During the fermentation process, the enzyme system synthesized by Aspergillus niger itself enzymatically hydrolyzes and saccharifies the sugar solution into glucose and fructose suitable for direct use by Aspergillus niger, and then metabolizes and synthesizes citric acid. The fermentation period is generally about 60 hours, and the fermentation acidity is 14. About % stops fermentation and puts tank. [0003] The...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C12P7/48C12R1/685
Inventor 周勇满云杨儒文章辉平廖四祥
Owner COFCO BIOTECHNOLOGY CO LTD
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