Lactobacillus delbrueckiisubsp.lactis and preparation method of bacteriocin thereof capable of resisting Listeria monocytogenes
A technology of Lactobacillus delbrueckii and lactic acid subspecies, applied in the field of microorganisms, to achieve the effect of simple extraction process, simple operation and convenient source
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Embodiment 1
[0029] The percentages in the following examples are volume percentages unless otherwise specified. Example 1. Screening and identification of lactic acid bacteria strain zhang-LF with anti-Listeria monocytogenes activity
[0030] 1. Screening of lactic acid bacteria strain zhang-LF with anti-Listeria monocytogenes activity
[0031] (1) Preliminary screening of lactic acid bacteria strain zhang-LF with anti-Listeria monocytogenes activity
[0032] Take 1 g of the ground dried fish product powder and put it into 9 mL of sterile saline, shake it fully for 20 min to make a suspension, and dilute it 10 times to 10 -5 ~10 -8 Spread the sample suspensions of each dilution on the MRS selective medium containing calcium carbonate, incubate at 37°C for 24 hours, and then carry out Gram staining, depending on the individual shape and purity. Transfer to inoculate in MRS liquid medium, enrich the bacteria for 2 to 3 generations at 37°C, centrifuge to get the fermentation supernatant, ...
Embodiment 2
[0068] Embodiment 2, Lactobacillus delbrueckii lactic acid subspecies zhang-LF bacteriocin extraction method
[0069] 1. The fermentation process conditions of bacteriocin
[0070] Medium components (w / v) for culturing Lactobacillus delbrueckii lactic acid subsp. zhang-LF producing bacteriocin: tryptone 1%, beef extract 1%, yeast extract powder 0.5%, triammonium citrate 0.2%, glucose 2%, Tween-80 0.1%, sodium acetate 0.5%, dipotassium hydrogen phosphate 0.2%, magnesium sulfate 0.05%, manganese sulfate 0.025%, 0.07MPa sterilization for 20min.
[0071] Fermentation process conditions for producing bacteriocin: fermentation temperature 37° C., fermentation time 20 h, initial pH of the culture medium 6.0, inoculum size 1%.
[0072] 2. Extraction method and potency analysis of bacteriocin in fermentation broth
[0073] (1) Extraction method of bacteriocin The purpose of separation and purification of bacteriocin is to extract the target protein and purify it to reach the required...
Embodiment 3
[0082] Example 3, a simple and effective purification method of Lactobacillus delbrueckii lactic acid subspecies zhang-LF bacteriocin
[0083] 1. Purification method of Lactobacillus delbrueckii lactic acid subsp. zhang-LF bacteriocin
[0084]The crude bacteriocin was redissolved in citric acid-sodium citrate buffer at pH 3.0, and the bacteriocin was purified by SP SepharoseFast Flow cation exchange chromatography; the elution condition of cation exchange chromatography was: the flow rate was 1ml / min, pH 3.0 citric acid-sodium citrate buffer containing 0.1-0.5NaCl for linear gradient elution, collect the solution with a large absorption peak at 280nm; put the collected solution into a pretreated dialysis bag at 4°C Dialyze in deionized water for 24 hours to remove salt, and the dialysate is the purified product of bacteriocin.
[0085] 2. Evaluation of bacteriocin purification effect
[0086] The total protein content was determined by Coomassie Brilliant Blue G-250 staining...
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