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Lactobacillus curvatus for producing bacteriocin, and application thereof

A technology of Lactobacillus campylobacter and bacteriocin, applied in the field of microorganisms, can solve the problems of poor solubility and low stability, and achieve the effect of obvious bacteriostatic effect.

Active Publication Date: 2017-04-26
JIANGNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, because Nisin only has an inhibitory effect on some Gram-positive bacteria, and has poor solubility and low stability under neutral conditions, the application of Nisin in food preservation and preservation is limited.

Method used

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  • Lactobacillus curvatus for producing bacteriocin, and application thereof
  • Lactobacillus curvatus for producing bacteriocin, and application thereof
  • Lactobacillus curvatus for producing bacteriocin, and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Example 1: Screening and identification of bacteriocin-producing lactic acid bacteria

[0024] Preparation of MRS medium: 10g of peptone, 10g of beef extract, 5g of yeast extract, 20g of glucose, 5g of anhydrous sodium acetate, 2g of diammonium hydrogen citrate, 2.62g of dipotassium hydrogen phosphate, 0.58g of magnesium sulfate heptahydrate, Water manganese sulfate 0.19g, Tween-801mL, add distilled water to 1L, pH 6.2-6.4.

[0025] Preparation of TSBYE medium: 30g of Tryptone soya broth (TSB), 6g of yeast extract, and distilled water to 1L, pH 7.2-7.4.

[0026] Preparation of solid medium: add 1.5% to 2.0% agar to the liquid medium.

[0027] (1) Isolation and purification of lactic acid bacteria

[0028] The used pickle materials of the present invention are all self-made, and its preparation method is: vegetables (cabbage, beans, white radish) are washed clean, mix with salt, capsicum, spices, put into the pickle tank and seal, place in a cool and dry place, 20 It ...

Embodiment 2

[0034] Example 2: Thermotolerance of Lactobacillus flexus SK1 bacteriocin

[0035] Bacteriocin activity was determined by the Oxford cup serial two-fold dilution method, and the indicator bacterium was Listeria monocytogenes. One activity unit (AU) is defined as the minimum amount of bacteriocin that can make the indicator bacteria produce a clear transparent circle. The bacteriocin activity of the solution (AU / mL) = 2 n ×(1000 / x). n represents the maximum number of serial two-fold dilutions of the bacteriocin solution that caused the indicator bacteria to produce an inhibition zone; x represents the volume (μL) of the bacteriocin solution added to each well. The diluent used for the determination of viability was 20 mM citrate buffer, pH 6.0.

[0036] Preparation of SK1 bacteriocin samples: Inoculate Lactobacillus flexus SK1 into 5mL MRS liquid medium, culture at 30°C for 24h, transfer to 50mL MRS liquid medium with 3% inoculum size, culture at 30°C for 24h, ferment the fe...

Embodiment 3

[0040] Embodiment 3: acid and alkali resistance of Lactobacillus flexus SK1 bacteriocin

[0041] The determination method of bacteriocin activity is the same as in Example 2, and the preparation method of SK1 bacteriocin sample is basically the same as in Example 2, but cultured at 20° C. for 48 hours after transfer.

[0042] Determination of acid and alkali resistance of SK1 bacteriocin samples: Adjust the SK1 bacteriocin samples to different pH values ​​(pH 2-10) with 5M NaOH or 4M HCl, store them at 25°C for 2 hours, then return them to pH 6.0, and finally pass The residual activity was determined by the Oxford cup method. The results are shown in Table 2. The SK1 bacteriocin sample has relatively good acid resistance. It can retain all the activity when stored at pH 2-6 for 2 hours, and has a certain alkali resistance. It can still retain half of the activity when stored at pH 7-10 for 2 hours.

[0043] Table 2 The acid and alkali resistance of Lactobacillus flexus SK1 b...

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Abstract

The invention discloses a Lactobacillus curvatus for producing bacteriocin. The preservation number of the Lactobacillus curvatus is CCTCC M2016540. The bacteriocin produced by the above strain has antibacterial activity on Listeria monocytogenes and Enterococcus faecalis, has very good heat and acid resistance, and can be rapidly hydrolyzed by multiple proteases, so no bacteriocin is residual. A fermentation supernatant of the strain can be directly used as a liquid bacteriocin product, and is dried to obtain a powdery bacteriocin product. The fermentation liquid of the strain undergoes three-step pH adjustment to obtain a pure bacteriocin product. Compared with chemical antiseptics and antibiotics, the bacteriocin produced by the strain, which can be enzymatically hydrolyzed by the proteases, has the advantages of greenness, healthiness, no residual, no side effects and no medicine resistance.

Description

technical field [0001] The invention relates to the technical field of microbes, in particular to a strain of bacteriocin-producing lactic acid bacteria that can not only inhibit the growth of Listeria monocytogenes but also more effectively inhibit the growth of Enterococcus faecalis. Background technique [0002] Food is often contaminated by spoilage microorganisms and pathogenic microorganisms during processing, storage, transportation, etc., which can cause foodborne diseases. In order to prevent food spoilage and deterioration caused by the growth of spoilage bacteria and pathogenic bacteria in food, it is necessary to add food preservatives. Lack of. Most commonly used food preservatives are chemical preservatives. However, in recent years, vicious food safety incidents have occurred continuously, most of which are new food safety problems caused by the excessive use of food additives. As a type of food additives, chemical preservatives have certain safety hazards, a...

Claims

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Application Information

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IPC IPC(8): C12N1/20C12P21/00A23L3/3463C12R1/225
CPCA23L3/3463C07K14/335C12P21/00C12N1/205C12R2001/225
Inventor 史锋李永富张美玲
Owner JIANGNAN UNIV
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