Improvement Of Vancomycin Producing Strain Amycolatopsis Orientalis By Rational Screening And Optimization Of Its Fermentative Technology

Based on the biosynthetic pathway and metabolic regulation, a rational selection procedure was performed to obtain a new vancomycin high-producing strain Amycolatopsis orientalis. At first, the most suitable production medium for rational seletion of the parent strain A. orientalis 1-6 was established by orthonormal design method. With the optimal medium, the productivity of A. orientalis 1-6 was raised 21.5%. On this basis, a rational screening was adopted to select a strain which could grow well on the medium with high concentration of 0.5%NaAc, 0.7%Na2HPC>4and lOOOu/ml vancomycin. By above methods, a high-producing strain 7-9 was obtained. The productivity reaches 4800u/ml, which is increased by 98% in comparison with that of the parent strain 1-6. Subculture test indicated that the hereditary character of high productivity of A. orientalis 7-9 was stable.The productivity of A. orientalis 7-9 in shake flasks was raised 14.3% further after optimization of the fermentation medium. The effects of inorganic salts, temperature, seed age, dissolved oxygen, shearing strength and precursors were studied in shake flaske. The optimal concentration of KH2PO4 and KNOa was 0.01%, 0.4%, respectively. In the course of vancomycin fermentation, the optimal temperature for vancomycin biosynthesis is 25 癈. Vancomycin fermentation needs high dissolved oxygen and is not very sensitive to shearing strength. With the optimal fermentation medium and condition, feeding 0.2% NaAc as precursor after 48h of incubation, the productivity of A. orientalis 7-9 reaches 6430u/ml.Based on the results in shake flasks, vancomycin fermentation was scaled up in a 15L fermentor, and a productivity of 4996u/ml was obtained.