Method for improving tolerance of erythromycin-producing strain against n-propanol through mutagenesis

Abstract

The invention discloses a method for improving the tolerance of erythromycin-producing strain against n-propanol through mutagenesis. The method comprises the steps that: (1) an erythromycin-producing strain is adopted as an initial strain, and is pre-cultured for 7 days on a slant culture medium; (2) the pre-cultured erythromycin-producing strain is subjected to ultraviolet mutagenesis, wherein the strain is irradiated for 3min under conditions of an ultraviolet lamp with a power of 15W and a fixed distance of 20cm; and the obtained product is instantly smeared on a culture medium plate; (3) live colonies after mutagenesis are subjected to ion beam irradiation mutagenesis, wherein a mutagenesis temperature is 25 DEG C and mutagenesis dose is 55Gy; after mutagenesis, culture medium plate pre-screening and shaking flask fermentation secondary-screening are carried out, and the obtained live colonies are the mutant erythromycin-producing strain with tolerance to n-propanol. With the method, the mutant erythromycin-producing strain with tolerance to high-concentration n-propanol is obtained. The n-propanol tolerance concentration is higher than 2%. Therefore, erythromycin-producing strain tolerance against n-propanol is improved, such that n-propanol concentration in a culture medium can be increased. Under a condition that producing strain conversion rate is unchanged, with the increasing of n-propanol concentration, erythromycin yield is increased. A draw-off titer of a 100L fermentation tank can be higher than 13000u / ml.

Description

technical field [0001] The invention relates to the field of bioengineering, in particular to a method for increasing the yield of erythromycin by means of microbial mutagenesis. Background technique [0002] Erythromycin is a macrolide antibiotic with broad-spectrum antibacterial activity. to G + Bacteria have a strong antibacterial effect, especially effective against penicillin-resistant Staphylococcus aureus. It has a strong inhibitory effect on rickettsia, mycoplasma and spirochete. It also has inhibitory effect on amoeba and trichomonas. [0003] Erythromycin is an alkaline antibiotic isolated from the culture broth of Streptomyces erythromycin, and later isolated from the fermentation broth, erythromycin A, B, C, D, E and other components, of which erythromycin Vitamin A is the main component, which has strong antibacterial activity and less toxic and side effects; other components have weak antibacterial activity and greater toxic and side effects than A. Common...

AI Technical Summary

Problems solved by technology

However, adding n-propanol in the early stage of fermentation will interfere with the growth of mycelium, thereby reducing the synthesis of antibiotics, and the residual concentration of exogenous premise in the fermentation broth is too high, which will poison the production bacteria and is not conducive to the synthesis of antibiotics