Research On Antibiotic Substances Orange Pigment And Citrinin Produced By Monascus Fermentation

The dissertation focuses on the antibiotic substances produced by Monascus, orange pigment and Citrinin. The main research contents and results are as follows:(1) Disc papers and Oxford cups were used to ascertain bacteriostatic effect of Hongqu. Using 70% ethanol and water as solvent, the extraction inhibited Bacillus subtilis, Bacillus cereus and Staphylococcus aureus and had no effect on E.coli, Salmonella. Typhi, yeasts and algae.(2) Hongqu contains three pigments, such as red, orange, and yellow pigments. The three pigments were separated by absorption column chromatograph. Then, TLC was used to purify them, and antibiotic experiments were made to define which was the main antibiotic substance. Results showed, orange pigment was the major antibiotic substance, and it could inhibit bacteria ,but had no effect on yeasts and algae. The diameter of the inhibition zone was directly proportional to the value of absorption of orange pigment.(3) Orange pigment could be oxidized with hydrogen peroxide to yellow pigment . Concentration of H2O2 was proportional to creation of yellow pigment. The quantity of orange pigment was influenced by the nitrogen source of the culture medium .(4) TLC method was set up to detect Citrinin in Hongqu. Extraction by 70% ethanol , developments were performed, in one direction, with chloroform -acetone (9:l,v/v),and then toluene-ethyl acetate-formic acid (6:3:1, v/v/v). Samples was extracted by water, the extraction was developed in dichloromethane-acetone(9:1,v/v), then chloroform -methanol -water (16:6:0.5) .Minimize quantity of Citrinin detected is 0.1 u g.(5) Study on decrease of Citrinin in Hongqu was conducted.