Studies On Cinnamic Aldehyde Microemulsion Preparation And The Mechanism Of Gram-positive Bacteria Sterilization

Cinnamic aldehyde is the important active ingredient in traditional Chinese medicinecinnamon, it has good anticorrosive antibacterial, health care, and so on, and is widely used infood industry, pharmaceutical industry and other industries. Cinnamaldehyde, therefore, becomethe hot spot of current research, and cinnamaldehyde low solubility in water, the characteristics ofeasy oxidation, become the disadvantages of cinnamaldehyde applications. The development ofthe microemulsion has become one of the the main technical solves low solubility. Previousstudies found that cinnamaldehyde have not inhibitory effect on Bacillus subtilis, and Bacilluscinnamic aldehyde microemulsion on good inhibitory effect, the mechanism is unclear. The issuewith Bacillus subtilis and Staphylococcus aureus for the study, on the one hand contrastcinnamaldehyde and cinnamic aldehyde microemulsion were Bacillus subtilis and Staphylococcusaureus bactericidal effect, and contrast cinnamic aldehyde and cationic antimicrobial peptides,respectively hay bactericidal effect of Bacillus and Staphylococcus aureus, a preliminary inquirycinnamic aldehyde microemulsion bactericidal mechanism of Gram-positive bacteria. On theother hand, through the Red gene knockout technology successfully acquired Staphylococcusaureus dltD mutant gene deletion, analysis cinnam aldehyde and cinnamic aldehydemicroemulsion on the bactericidal effect of mutants to reveal cinnamic aldehyde microemulsionon Gram-positive bacteria sterilization mechanism. The specific study as follows:1Preparation of cinnamaldehyde microemulsionStudying the cinnamaldehyde microemulsion, selecting the appropriate surfactant andco-surfactant is critical of microemulsion produced. Suitable surfactants and co-surfactants, caneffectively improve the coating properties, but also has a good stability after the formation of the microemulsion. Tween-80is a good microemulsion formed cinnamaldehyde surfactant, surfactantand co-surfactant (ethyl acetate) Km mass ratio of2:1better microemulsion formedcinnamaldehyde.2Cinnamaldehyde microemulsion and cationic antimicrobial peptide on bacillus subtilisand bactericidal effect of staphylococcus aureusCinnamic aldehyde due nanoemulsion will be up and making the original packagebecomes positively charged surface uncharged. EDTA is a divalent metal cation chelator, addingEDTA can chelate divalent metal cations on the surface of bacillus subtilis and staphylococcusbacteria, furthermore, it makes Bacillus subtilis and Staphylococcus aureus cell surface of the cellwall acid esterification not brought exposed negative charge, the external electric field into themembrane pore size is reduced, the surface uncharged cinnamaldehyde and subtilisin positivelycharged more easily enter. Bactericidal effect will be enhanced.3Preliminary inquiry sterilization mechanismThe amount of Divalent cations on the surface of the bacillus subtilis that determinescinnamic aldehyde on its sterilization effect is good or bad,because of the degree of esterificationof cell wall acid of the cell membrane surface determines the amount of divalent cations, the cellwall acid is a high degree of ester cell surface cation with less, whereas the cell surface cationbrought on much. And the amount of dlt gene expression determines the degree of esterification ofcell wall acid, dlt gene expression more amount of cell wall acid esterification degree is high.4Preparation of aureus dltD mutationTo staphylococcus aureus object, we use Red homologous recombination technology,successfully with staphylococcus aureus dltD mutants. This study preliminarily explores the Red recombinant technology that makes staphylococcus aureus mutant experimental conditions,determining the test in the process of L-induction time and the concentration of the Arab xylan, theoptimal induced concentration of50mmol/L, and the arabinose induction time also explored theproviso that the reaction was terminated by adding1hour before induction of its relatively good.And the recovery time after electrotransformation in one hour to control.5Role in the whole sterilization validation positive surface chargeBacillus subtilis168and Staphylococcus aureus dltD mutant cell surface cell wall acidesterification degree is weak, the cell surface of S. aureus cell wall acid esterification strongdegree. dltD gene may affect the esterification degree of cell surface, thereby changing the surfacecharge. Cinnamic aldehyde influence cell surface is dependent on divalent cations (magnesium ion)on the bactericidal effect of Gram-positive bacteria. dltD gene expression, the more the degree ofesterification on the cell surface, the stronger, the less surface cations, cinnamic aldehyde lesslikely to enter, bactericidal effect will be weaker.