Rhubarb horsetails Erwinia sp. and its application in preparation of isomaltulose

A technology of isomaltulose and Erwinia, which is applied in the fields of fermentation engineering and enzyme engineering, and can solve the problems of reducing the yield of the target product, unstable yield, and increased production cost.

Inactive Publication Date: 2008-06-18
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the above-mentioned bacteria can convert sucrose into isomaltulose, the yield is very unstable, and the conversion rate is 8-86%.
Moreover, in the process of catalyzing the conversion of sucrose by these isomaltulose-producing strains, in addition to the main product, trehalulose, isomaltose, isomelezitose, and by

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Incline medium: peptone 10g / L, beef extract 3g / L, NaCl 5g / L, agar 20g / L, pH7.0.

[0036] Shake flask medium: sucrose 50g / L, yeast extract 10g / L, Na 3 PO 4 12H 2 O 5g / L, pH7.0.

[0037] Cultivate Erwinia rhubarb NX-5 CGMCC No.2222 on a slant medium at 30°C for 24 hours, then place a ring of the bacteria in a shaker flask medium, culture it at 30°C for 10 hours, and shake the flask at a rotational speed of 200r / min. The content of thalline in the liquid is 20g / L, and the enzyme production reaches 2.5~5.0U / ml, transforms with free cells, takes by weighing 10g cells and adds in the sucrose solution of 100ml450g / L (the amount of cells added is converted 1L55% per 100g cells sucrose solution), under the condition of 30°C, shake the shake flask to produce isomaltulose, and the reaction time is 8h. After the reaction is terminated, the substrate conversion rate and product concentration are measured. The conversion rate of sucrose is 99.5%, and the conversion rate of isomal...

Embodiment 2

[0039] With 50g / L maltose as the carbon source, 5g / L bean cake powder as the nitrogen source, other components of the culture medium and bacterial cell culture conditions are the same as in Example 1, prepare 1.5% sodium alginate colloidal solution, and a bacterial suspension prepared with physiological saline After mixing evenly, add 8% diatomaceous earth to absorb, and drop 2% CaCl with a syringe 2 Solidify in the solution to make spherical immobilized cells with a diameter of about 3 ~ 4mm, put them in a refrigerator at 4°C for several hours, then pour off the supernatant, wash twice with distilled water, and wrap 10g of wet cells with sodium alginate 20 g of immobilized cells were buried and converted into 100 ml of 550 g / L sucrose solution in a shake flask under the condition of 30 ° C. The conversion time of each batch was 10 h, and 40 batches were converted, and the average conversion rate of sucrose was 99.5%. The average conversion rate of maltulose was 88%.

Embodiment 3

[0041] Dilute 225g of glucose, 45g of corn steep liquor, 22.5g of NaCl, pH 6.0, to 4.5L with water to prepare a culture medium, put it into a 7.5L glass stirred fermenter, and steam sterilize at 121°C for 15min. Prepare seed medium: sucrose 50g / L, yeast extract 10g / L, Na 2 HPO 4 12H 2 O 5g / L, pH6.0. Add a ring of Erwinia rhubarb NX-5 CGMCC No.2222 to the seed medium, culture at 30°C for 8 hours to obtain a seed solution, and insert the seed solution into the cooled fermentation medium according to the inoculation amount of 3% of the volume of the fermentation solution , and cultivated at 30°C (ventilation rate 1vvm, stirring speed 600r / min) for 12h. The fermented liquid is subjected to bacterial filtration treatment in an ultrafilter, and the molecular weight cut-off of the ultrafiltration membrane is 10 6 Dalton, the operating pressure is 0.2MPa, the temperature is controlled at 50°C, and the membrane surface velocity is 4m / s. After immobilizing 90g of bacteria obtained b...

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Abstract

The invention discloses an Erwiniarhapontici NX-5 and a method of producing sucrose isomerase for the preparation of isomaltulose by the Erwiniarhapontici. The strain CGMCC No.2222 is inoculated in an aseptic culture medium containing carbon source, nitrogen source, inorganic salt and water for the aerobic culture. Cells containing the sucrose isomerase are obtained after the centrifugation or the ultrafiltration. Furthermore, dissociative cells containing the sucrose isomerase are directly adopted to be converted into sucrose to generate the isomaltulose or immobilized cells containing the sucrose isomerase which are then converted into the sucrose isomerase to generate the isomaltulose. With the strain adopted, the conversion rate of the sucrose reaches to 99.5 percent (w/w), the conversion rate of the isomaltulose reaches to 90 percent, and the concentration of the isomaltulose in the conversion solution reaches to 500g/L. no hydrolysis side effects happen. Almost no glucose and fructose are contained in the conversion solution. The product, the isomaltulose, can not be converted into other components with the reaction. The invention is beneficial to the industrial production of the isomaltulose.

Description

technical field [0001] The invention belongs to the technical fields of fermentation engineering and enzyme engineering, and relates to a microbial strain Erwinia rhapontici NX-5 producing sucrose isomerase and its use in the production of isomaltulose. Background technique [0002] Isomaltulose (6-O-α-D-glucopyranosyl-D-fructose, Isomaltulose) is a reducing sugar that exists in small amounts in natural honey and beet juice, and has the most similar physical properties to sucrose and taste. As a substitute for sucrose, it has the following advantages: (1) Since it releases monosaccharides in the blood slower than sucrose and does not stimulate insulin secretion after being eaten by the human body, it can be eaten by diabetics and people who lose weight; The oral streptococcus that causes dental caries metabolizes and does not corrode teeth; (3) In the microflora of the human intestine, it selectively stimulates the growth of bifidobacteria; (4) It has high food safety perfo...

Claims

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Application Information

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IPC IPC(8): C12P19/12C12R1/18
Inventor 徐虹李莎环民霞林璐蔡恒欧阳平凯
Owner NANJING UNIV OF TECH
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