Repeated batch production of vancomycin using synthetic cotton fibers
The production of vancomycin by free and immobilized cells of Amycolatopsis orientalis was investigated. The influence of immobilization through entrapment in Ca-alginate beads and adsorption on different materials including synthetic cotton fibers, glass wool, cotton cloth and absorbed cotton on the production was compared to free cells in shake flask cultures. Cells entrapped in Ca-alginate beads gave low antibiotic yield compared to free cells. Immobilization of A. orientalis on synthetic cotton fibers as well as on glass wool gave the highest vancomycin yield after 4 days of incubation and were the best support materials for cell immobilization and vancomycin yield was about two fold higher than that produced by freely suspended cells under the same cultivation conditions. The effect of medium volume with immobilized cells revealed that in case of 25 ml fermentation medium, the production of vancomycin was 50% higher than the use of 50 ml volume. The reuse of the immobilized cells on synthetic cotton fiber five times over a period of 20 days repeated batch fermentation was investigated. A slight decrease in vancomycin production was noticed in the three last cycles. In general, immobilization minimized the lag time for both cell growth and vancomycin production. These results suggest that immobilization by adsorption is promising for industrial application.
Key words: Vancomycin, immobilization, fermentation and Amycolatopsis orientalis.