Optimization Of The Component In Spiramycin (EP)

Based on the metabolic pathway of spiramycin, mutant strains, with resistance of precursor acid, were selected by using complex mutagenesis of NTG and microwave and binding to the preliminary screening of agar block. And then several optimum strains were chosen by second screening with shaking flask culture method. Spiramycin production is increased by 7-17%. The components of One of mutant strains which the relative percentage of impurities UNK2,UNK4 and B have reduced from 5.73% to 5.22%, from 1.92% to 1.42%, from0.53% to 0.49% respectively, were optimized. Impurity D has removed basically and the effective component SPM I has increased from 86.48% to 91.63% accordingly.The purpose of the experiment was to optimize the component without decreasing the yield of spiramycin with productive technology by adding the metal ions in the process. At first, the significant metal ion which is effective to the impurities of spiramycin were selected through lacunary method of medium component, and in order to confirm the optimum addition time, variation of related metal ions content in fermentation were detected with ICP-AES. And the optimum addition concentration was determined by the steepest ascent search and central combination response surface design. The optimum result was adding 0.07g/100mL zinc sulfate and 0.016g/100mL cobalt chloride at 96h. The titer of spiramycin has increase from 19384U/mL to 22587U/mL by using the optimum condition which was increased by 16% compared with control. It was significant that the relative percentage of impurity B have reduced from 0.64% to 0.23%.Optimizing the medium of seed and cultural time of seed was to control the quality of seed. The original first seed medium was replaced by original second seed medium and the optimum cultural time was 48h in first grade and 26h in second grade, respectively.The replaced seed culture medium has resolved the problem of less vigorous and instability in fermentation process. Besides, supplementing choline chloride which is one of methylation reagents can promote the methylation, thus leading to the decrease of the relative impurities. One-factor design experiment was used to determine the optimum supplementing condition of choline chloride. Finally enlarge cultivation on fermenter resulted in optimizing various component which the relative percentage of impurities UNK2 and B was decreased from 6.57% to 6.35% and 1.17 to 0.55% respectively. The effective component SPM I has increased from 85.56% to 89.98% accordingly. It was significant that impurity UNK4 have reduced from 2.11% to 1.18%.