Method for isolating and purifying bacteriocin against drug-resistant Staphylococcus aureus

A method for isolating and purifying Lactobacillus rhamnosus ZFM216 bacteriocin, comprising the following steps:

• 1) preparing L. rhamnosus ZFM216 fermentation supernatant:
• inoculating MRS liquid medium with L. rhamnosus ZFM216 for fermentation, and
• centrifuging the fermentation broth to obtain the fermentation supernatant;
• the preservation number of L. rhamnosus ZFM216 being CCTCC M 2020325;
• 2) treating the fermentation supernatant with macroporous adsorption resin to obtain a crude protein extract;
• 3) isolating the crude protein extract by gel chromatography to obtain a preliminary purified protein solution;
• and then performing purification by reversed-phase high performance liquid chromatography (RP-HPLC) to obtain an L. rhamnosus ZFM216 bacteriocin solution;
• wherein in step 1), MRS liquid medium, pH 6.4, is inoculated with L. rhamnosus ZFM216 cultured to the logarithmic growth phase at an inoculum concentration of 2% v/v for performing stationary culture at 37° C. for 21 h;
• and the obtained fermentation broth is centrifuged at 8000 rpm, 4° C., for 30 min to obtain the fermentation supernatant;
• in step 2), 1 L of the fermentation supernatant is allowed to flow through the macroporous adsorption resin, rinsed with 2 L of ultrapure water at a flow rate of 2 mL/min, and then eluted with 500 mL of 20% ethanol at a flow rate of 2 mL/min, and the eluate is a crude protein extract;
• and
• during the isolation by gel chromatography in step 3), the crude protein extract is subjected to gel chromatography and eluted with ultrapure water as the eluent at a flow rate of 1 mL/min;
• and the eluate corresponding to the first absorption peak under the absorbance of 215 nm/280 nm is collected to obtain a preliminary purified protein solution;
• and then the preliminary purified protein solution is filtered through a 0.22 m membrane, and precisely purified by preparative C18 reversed-phase high performance liquid chromatography (RP-HPLC) with a chromatographic column at an injection volume of 5 mL to obtain an L. rhamnosus ZFM216 bacteriocin solution.