Studies On The Antibiotics From Rhizopus Chinesis 12th

The fermentation process of the antibiotics from Rhizopus chinesis 12th, mechanism of action of the antibiotics and its properties were studied, and the agar diffusion assay was also discussed. The factors that influenced the size of inhibitory zone were investigated. Some parameters were determined such as the concentration of indicator strain (the 9 hours culture of the strain diluted 1/10), the concentration of agar in the detecting plate (0.6%) etc., so that the assaying results could be repeated and the method was of higher sensitivity. By single factor and Response Surface Analysis and on the basis of studies on the relationship between the morpha of Rhizopus chinesis 12th and the activity of the antibiotic, the optimum medium (5% bran drench, 1% corn steep liquor, pH4.0 ) and the optimum condition were determined. The process was the inoculum, which were cultured at 30CC, 170r/min for 10 hours, were inoculated to lOOmL fermentation medium, the inoculum volume was 5.5mL. The fermentation conditions but the 1 50r/min shaking speed were same as those of the inoculum culture and the course of fermentation was 48 hours. With the help of transmission electron microscope and other methods, it was found that the antibiotics?mechanism of action on the indicator strain was bacteriolysis. Some properites of the crude extract of antibiotics were studied, in order to provide scientific basis for isolation and purification.