Study On The Separation And Purification Of Plant Lactobacillus And Its Properties

The plantaricin 1.557 was a bacteriocin produced by Lactobacillus plantarum 1.557,a strain isolated from fermentation of auerkraut medium.The plantaricin was seperation and purification,the phychemical properties and structure of plantaricin were determined in this experiment.The relation between structure and properties of plantaricin was understanded,the study of plantaricin providing theoretical basis for production and application as a potential natural biopreservative in the food industy.The plantaricin was purfied via method of Yang,DEAE-Sepharose Fast Flow?Sephadex G-50 gel chromatography and preparative-grade high performance liquid chromatography.After Sephadex G-50 gel chromatography,the activity of plantaricin was 5.81×104AU/mg.The purification of plantaricin was 38.7 times than fermentation,the final extraction was 1.86%.The molecular mass of plantaricin was about 9 kDa determined by SDS-PAGE electrophoresis.The plantaricin activity was stable from pH2-10 for 2h at room temperature;for 20 min at 20?-100?;with 10%formaldehyde,10%ethanol,10%glycerol and 5 mmol/L of SDS,5 mmol/L EDTA,1%and 1%H2O2,Tween-20,Tween-80,Triton X-114 for 2h,respectively.The effect of the metal ions Ca2+,K+ and Na+ on plantaricin was positive,but the effect of the metal ion Fe3+,Al3+,Pb2+ and Hg2+,Mg2+,Cu2+,Fe2+,Ba2+,Mn2+,Zn2+ was negative.Not only the plantaricin had a broad antimicrobial activity against some gram positive bacteria,such as Staphylococcus aureus and Bacillus cereus,but also against some gram-negative bacteria such as Pseudomonas aeruginosa and Shigella in different degrees of inhibition,respectively.The structure of plantaricin was determined via the preparation of high performance liquid chromatography(HPLC).The plantaricin was determined via infrared spectrum,the results shew that presence of amide bond with infrared absorption peak at 1662 cm-1,the secondary structure of plantaricin existed element ?-sheet.