Arthrobacter mutant strain, method for producing lactase from mutant strain and method for preparing lactulose by using lactase

The technology of a mutant strain, Arthrobacter, is applied in the field of catalyzing the synthesis of lactulose from lactose and fructose, which can solve the problems of complex process, high cost and low product yield, and achieve the effect of easy purification, convenient operation and high product purity

Inactive Publication Date: 2011-08-31
JIANGNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, low product yield, complicated process and high cost are still problems to be solved in the preparation of lactulose by chemical method
[0004] In contrast, the enzymatic lactulose preparation can avoid problems such as product degradation and colored by-products. At present, the research at home and abroad is still in its infancy.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] The Arthrobacter sp.jnsb-2 mutant strain of the present invention can be applied to the production of lactase by fermentation, specifically as follows:

[0038] (1) Preparation of culture medium

[0039] Solid medium: peptone 1%, yeast extract 0.5%, NaCl 1%, pH 7.0, agar 2%, sterilized at 121°C for 20min. Seed medium: 1% peptone, 0.5% yeast extract, 1% NaCl, pH 7.0, sterilized at 121°C for 20min. Fermentation medium: lactose 2%, yeast extract 1.4%, FeCl 3 1.5mmol / L, pH7.0, sterilized at 121°C for 20min.

[0040] (2) Strain fermentation and cultivation

[0041] The Arthrobacter sp.jnsb-2 mutant strain Arthrobacter sp.jnsb-2 was activated on a solid slope for 24 hours, and then a loop of the bacteria was added to the seed medium, and incubated at a constant temperature of 30° C. for 12 hours, and the rotation speed of the shake flask was 200 r / min. The above-mentioned seed bacteria suspension was inoculated into the fermentation medium at 10% (v / v), cultured at a con...

Embodiment 2

[0044] It is basically the same as Example 1, the difference is:

[0045] The fermentation medium used in the step (1) is lactose 1%, corn steep liquor 2.2%, ferric chloride 1.5mmol / L; The fermentation culture condition after the inoculation in the step (2) is: 30 ℃ of constant temperature cultivation 18h, shake flask rotating speed 200r / min.

[0046] In step (3), the fermentation broth was centrifuged at 5000rpm for 15min to collect the cells, resuspended with the same volume of phosphate buffer (10mmol / L, pH7.0), disrupted by ultrasonic waves, centrifuged at 10000rpm for 15min, and the supernatant was obtained as the enzyme solution.

Embodiment 3

[0048] Basically the same as Example 1, the difference is: the fermentation medium is glucose 1%, peptone 1%, yeast extract 0.5%, KH 2 PO 4 20mmol / L, MgSO 4 .7H 2O 2.7mmol / L; the fermentation culture condition after inoculation in the step (2) is: 37 ℃ of constant temperature cultures 12h, shake flask rotating speed 200r / min.

[0049] Examples 1-3 are all methods for producing lactase using mutant Arthrobacter strains, wherein the carbon source, nitrogen source, and inorganic salt of the fermentation medium are not particularly limited, the culture conditions of the strains are extensive, and the operation is convenient.

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PUM

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Abstract

The invention belongs to the technical fields of food and biology, and discloses an Arthrobacter mutant strain (Arthrobacter sp.jnsb-2), a method for producing lactase by fermentation culturing of the mutant strain and a catalytic method for synthesizing lactulose from lactose and levulose by using the lactase as a catalyst. In the invention, the Arthrobacter mutant strain jnsb-2 is used as the strain of which the preservation number is CCTCC NO:M209210, and is subjected to fermentation culturing on a fermentation culture medium composed of a carbon source, a nitrogen source and inorganic salt, thus obtaining the lactase; and by using the lactase as a catalyst, lactose and levulose can be used as substrates and converted into the lactulose by an enzyme method. The lactase produced by the fermentation of the strain has the advantages of extensive culturing conditions, short enzyme production cycle and convenient operation process; and by using the enzyme method to convert the lactase into the lactulose, the defects that the product is easy to degrade and the colored byproduct is difficult to remove in the lactulose preparation process based on the chemical method are overcome, and a high product purity is achieved.

Description

technical field [0001] The invention relates to the field of food biotechnology, in particular to a mutant strain of Arthrobacter, a method for fermenting and culturing it to produce lactase, and a method for using the lactase as a catalyst to catalyze lactose and fructose to synthesize lactulose. Background technique [0002] Lactulose (Lactulose, 4-O-β-D-galactopy-ranosyl-D-fructose), also known as lactulose, is a disaccharide composed of galactose and fructose combined by β-1,4-glycosidic bonds. In 1930, Montgomery discovered lactulose for the first time. Since then, the research on the structure and physiological function of lactulose has progressed rapidly. So far, the main physiological functions of lactulose have been determined as follows: (1) promote the proliferation of bifidobacteria, adjust the balance of intestinal flora; (2) treat hepatic encephalopathy, reduce endotoxin; (3) catharsis, used for Chronic constipation; (4) used to monitor the permeability of the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C12N1/20C12N9/38C12P19/14C12R1/06
Inventor 唐蕾毛忠贵张建华杨瑞金孙慧慧刘莉
Owner JIANGNAN UNIV
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