Statistical optimization of medium components to improve the antibiotic activity of Streptomyces sp. 19G-317

Abstract

In this paper, fermentation parameters for the production of antibiotics by Streptomyces sp.19G-317 to enhance the antibiotic activity were optimized using a sequential optimization strategy, including the single factor, Plackett-Burman (PB) design, steepest ascent experiment and response surface methodology (RSM). Firstly, the basic medium, suitable carbon and nitrogen sources were selected by single factor test. Millet medium, maltose and tryptone had significant influences on antibiotics production. Maltose and tryptone were then proved to have remarkable effects on antibiotic activity among seven parameter (the selected carbon, nitrogen, initial pH, medium volume, rotary speed, temperature and inoculation volume) using PB design. Finally, steepest ascent experiment and RSM were used to further optimize the significant factors, optimized values were maltose 5.03%, tryptone 0.96%, NaCl 0.25%, CaCO3 0.20%, initial pH 8.0, medium volume (250 ml flask 125 ml), rotary speed 195 r/min, temperature 28℃ and inoculation volume 7.0%. An overall 38.30% increase in antibiotic activity was achieved under the optimized parameter as compared with the unoptimized parameter, from 23.5 to 14.5 mm. Key words: Antibiotic activity, fermentation condition, medium component, response surface methodology,Streptomyces sp.19G-317.