Research On Extraction And Separation Of Bacteriostatic Protein From Ginkgo Biloba Seeds

Ginkgo biloba has strong resistance on plant pathogenic bacteria infection. Manybacteriostatic ingredients have been found in Ginkgo biloba organizations. In order to furtherstudyed the properties of the bacteriostatic protein from ginkgo biloba seeds, bacteriostaticprotein were extracted and purificated from ginkgo biloba seeds. With corruption andfood-borne pathogenic bacteria in food as the research object, bacteriostatic activity andphysicochemical properties of bacteriostatic protein were invisitaged in this paper. Mainconclusions were as follows:（1）The optiminal extraction process of ginkgo biloba seeds proteins were obtained bysingle factor test and orthogonal test. Extraction effects of TBS method and PBS method werecompared. SDS-PAGE results showed the more protein bands were detected in the ginkgobiloba seeds proteins extracted by PBS method. The best technological parameters was thatsolid-liquid ratio1:20, extraction time12h, extracting concentration0.05mol/L, extraction pH7.0, the protein extraction rate reached the highest,90.67%.（2）Primary purified bacteriostatic protein were obtained after some water-solubleimpurities and miscellaneous protein from ginkgo biloba seeds proteins were removed by40%and80%saturation (NH4)2SO4precipitation. DEAE-Cellulose52was used for crude proteinseparation, sample concentration:10mg/mL, sample volume:10mL, elution velocity:5mL/min,staged elution:0.02mol/L pH7.0PBS (contains:0.1mol/L,0.3mol/L,0.8mol/L NaCl), thebacteriostatic protein from ginkgo biloba seeds was separated into three components: peak1,peak2, peak3. Bacteriostatic activity study found that the bacteriostatic activity of peak2wasvery weak, the bacteriostatic activity of peak1was stronger than the peak3.（3）In this experiment, seven types of bacteria and five types of fungi as indicatorbacteria. The results of bacteriostatic activity showed that, the peak1has strongest bacteriostaticactivity, including Klebsiella peneumoniae, Staphyloccocus aureus, Torulaspora delbrueckiiand Aspergillus niger. Bacteriostatic activity of peak1was significantly affected in different pH,pH6.0~8.0was the best pH range. Bacteriostatic activity of peak1was reduced by heating.Stability of bacteriostatic protein from ginkgo biloba seeds was studied. The results showed thestability of bacteriostatic protein from ginkgo biloba seeds was affected in different pH, thelowest solubility of bacteriostatic protein was in pH4.0solution. The solubility of bacteriostaticprotein was high and the properties was stability when the concentration of NaCl was0~6%.The stability of bacteriostatic protein from ginkgo biloba seeds was significantly affected indifferent temperature.