Effect of support materials on antibiotic MSW2000 production by immobilized Streptomyces violatus

Abstract

The production of an antibiotic by free and immobilized cells of Streptomyces violatus through entrapment or adsorption on different materials was investigated. S. violatus entrapped in Ca-alginate beads gave low antibiotic activity compared to the free cell or adsorbed cell, while the adsorption of S. violatus on sponge cubes yielded the highest antibiotic concentration after 4 days of incubation in static cultures. A starch concentration of 10g/L was optimum for the production of the antibiotic by adsorbed cells. The weight and size of the sponge cubes used for immobilization influenced production of the antibiotic and the optimum weight and size of the sponge were 0.8g and 1.0cm³, respectively, yielding a maximum antibiotic production of 280μg/ml. Maximum antibiotic production was obtained at an initial pH value of 7.5 and in an inoculum size of 3ml (spore suspension) per 50ml. The production of the antibiotic in a fixed-bed bioreactor reached a maximum value after 2 days of incubation at a circulation rate of 30ml/h. The immobilized cells in the bioreactor were reused seven successive times over a period of 14 days.