Purification, Characterization And Application Of Lipopeptides Produced By Bacillus Subtilis

Bacillus subtilis belongs to the genus Bacillus, and has a wide range of applications in agriculture, environmental control, medicine, food and washing chemistry.In this study, hydrochloric acid precipitate from the culture medium of Bacillus subtilis strains(B. subtilis),extvact by methanol, hexane elution a lipid peptide and tablet tests showed that the lipopeptide extract of cotton verticillium wilt pathogen Verticillium dahliae fungus has an significant inhibitory effect of more than9.5%g wilting, and a relative control efficiency of85.4%.The surfactin lipopeptide substance isolated from the preparative HPLC separation, and bio-surfactant for surfactin standard peak retention time consistent, and by the cyclic peptide, determined by the surface tension meter after the TLC ninhydrin experiment the surface tension of its aqueous solution can effectively reduce the surface tension of the solution, its critical micelle concentration (CMC) was determined as30mg/L, the initial judgment as surfactin. Its further MS found that the electros pray ionization mass spectrometry [M+H]+values were m/z1007.0,1021.0,1035.0goods and surfactin standard three homologues results.the difference value is14D,possibly predictive for methylene(-CH?)The result showed that the lipopeptide compounds isolated and purified from the fermentation broth of Bacillus subtilis contain the surfactin which can increase the catalytic activity of the lipase and β-glucosidase signifcantly and as a result provide a broad application prospects and important research value for the expansion of the industrial application of lipase and the enzymatic synthesis of β-glucoseglycosides to salidroside.The studies of the enzymatic synthesis of β-glucoseglycosides to salidroside showed that with surfactin, the yield of salidroside reached59.2%. Compared to other chemically synthesized surfactants, surfactin presented the the greatest impact to the activity of beta-glucosidase,which prove that surfactin can increase its activity effectively.We add Surfactin in the process ofe grease degradation catalyzed by lipase and compare the impact of which to the ability of lipase-catalyzation. The result revealed that under the conditions of Tris-HCI buffer pH7.5, the enzyme concentration of1%, temperature35℃, the minimum dosage of surfactin of lipase catalyzing the soybean oil to the maximum activity is400μL(2mg/mL). Under this condition, the catalytic efficiency increase43.1%and the enzymatic activity reached98U/g. the gas chromatography of the reaction product found that compared to chemical surfactants (SDS, quaternary ammonium, Tween-20),the component content of the product increase123.8%.