The Breeding Of Erythromycin And Optimization Of Fermentation Process

Erythromycin is a 14 membered macrolide antibiotic produced by Streptomyces.It has broad antimicrobial spectrum and wide clinical application.The production of erythromycin mainly provides raw materials for azithromycin workshop.In production,the main problem is low titer and low effective component.Therefore,it is of great significance to improve the production and quality of erythromycin through the breeding of erythromycin producing strains and optimization of fermentation technology.In this study,erythromycin producing strain HA-13 was used as the starting strain,and a high-yield mutant was obtained by physical and chemical mutagenesis and directed screening.Finally,a stable fusion protein was obtained by protoplast fusion.On this basis,the fermentation medium and culture conditions of the strain were optimized,and the fermentation conditions of the high yield fusion seed were verified on the 50 L fermentor,and the following results were obtained.1.The original strain was treated with ultraviolet,lithium chloride and DES mutagenesis,and a mutagenic strain of erythromycin was obtained: U-14-30,its potency was up to5478u/ml,which was 14.29% higher than that of the starting strain.2.Combined with the directional screening technique,the mutant B-14-30 resistant to propionic acid and the mutant H1-14-05 resistant to erythromycin were screened,and the two were fused to the protoplast,and a high and stable fusion seed R-15-11 was obtained.Its titer reached 6530u/ml,which was 36.2% higher than that of the original strain H-13-36.The passage and genetic stability test showed that the strain had good genetic stability.3.Using single factor experiment and orthogonal experiment design to optimize the culture condition and medium of high yield fusion seed.The optimum result is: p H7.0±0.1before sterilization,the optimum inoculation amount is 10%,the fermentation volume of shake flask: 60ml/500 ml,temperature 33±1 C,soybean cake powder 2.7%,corn pulp 0.22%,glucose 2.2% and ammonium sulfate 0.20%.After optimization,the titer of the control group was 20.88% higher than that of the control group.4.The effect of metal ion on fermentation was studied by single factor experiment and orthogonal experiment.The optimum proportion of three kinds of ion zinc chloride,cobalt chloride and sodium molybdate in the medium were 0.05%,0.01%,0.07%,and the fermentation titer was 16.13% higher than that of the control group.In this study,erythromycin high yield fusion seed was used as the starting strain,and the optimized process was verified on the 50 L tank.The titer of the canister was 21.7% higher than that of the starting strain.The content of main impurity Er B and Er C was lower than that of the control group of 2.58% and 1.38%,respectively.The high yield fusion polymer and50 L fermentor technology laid the foundation for industrial production.