The Study Of Spiramycin Biosynthesis

In this study,we were optimized to the Streptomyces spiramyceticus fermentation conditions,in order to increase the production of spiramycin and at the same time improve the effective components of spiramycin.At 48h,adding 1.2 mg/L of zinc ions into the fermentation medium,the spiramycin fermentation titer increased by 33.81%,the percentage of spiramycin?decreased by 3.76%and the percentage of spiramycin? increased by 4.2%compared with the control.Zinc ions addition relieved the inhibition of their metabolites,and then promote intracellular spiramycin released.At 3 6h,adding 2 mg/L vitamin B9 into fermentation medium,spiramycin fermentation titer increased by 19.29%,and the percentage of spiramycinI was also enhanced.The reason can be explained by vitamin B9 addition effect the biosynthesis of spiramycin? and Srm38 gene transcriptional level was 1.6 times compared with the control.Oleic acid with 1g/L was added into the seed culture medium,resulting in spiramycin fermentation titer increased by 15.41%.This can be mainly explained by that oleic acid addition reduced sugar consumption rate,and effect the growth of cells in seed culture stage.The dry weight of the control was 1.63 times compared with the oleic acid added,but there have no obvious effect in fermentation stage.And change mycelial morphology.The HMP pathway was also enhanced and glucose 6-phosphate dehydrogenase enzyme activity was 2.52 times and the concentration of NADPH was about 2.7 times compared with the control.The cell specific production rate was 1.33 times compared with that of control.Oleic acid with 1 g/L was added into the seed culture medium and then amplified to 15 L fermentor.The spiramycin fermentation titer increased up to 4022 U/ml,with stable pH value over the whole fermentation process.In the early stage of the fermentation,sugar consumption rate slower than the later period.And glucose 6-phosphate dehydrogenase enzyme activity and the concentration of NADPH remained at high level.