A method for screening high-yielding macrolactins marine bacillus using sea salt osmotic stress

Abstract

The invention discloses a method for screening high-yielding Macrolactins marine bacillus by using sea salt osmotic pressure stress. The invention takes 50 g / L sea salt osmotic pressure that significantly inhibits the growth of wild marine bacillus as the initial screening pressure to domesticate target strains, and after multiple subcultures After the strains were adapted to the osmotic stress of this concentration of sea salt, the sea salt concentration was increased to 60 g / L to start a new round of domestication, and so on. When the sea salt concentration increased to Ng / L, the strain could not grow, and the domestication process was terminated. Take (N-10) g / L sea salt-stressed domesticated bacterial liquid and coat the ISP2 solid medium containing (N-10) g / L sea salt to obtain a high-proportion high-yielding Macrolactin mutant strain. The invention uses the appropriate concentration of sea salt osmotic stress as the screening pressure combined with the adaptive domestication strategy, and efficiently selects and breeds high-yielding Macrolacins marine Bacillus mutant strains, and solves the dilemma that such strains lack efficient selection markers in the process of selecting and breeding excellent strain resources. .

Description

technical field [0001] The invention belongs to the technical field of microbial breeding, and in particular relates to a method for screening high-yield Macrolactins marine bacillus by utilizing sea salt osmotic pressure stress. Background technique [0002] Macrolactins are 24-membered macrolide compounds, mainly derived from marine Bacillus sp. and Actinomadura sp., containing more than 32 monomeric compounds, exhibiting various biological inhibitory activities such as anti-virus, anti-tumor and anti-bacteria. Compounds with broad-spectrum bioinhibitory activity have broad application potential in the fields of disease treatment and biological control of agricultural diseases and insect pests. The Boriss research team confirmed for the first time that the PKS type I gene cluster is involved in the synthesis of Macrolactins by analyzing the Bacillus amyloliquefaciens FZB42 genome. The entire gene cluster is about 54kb in size and consists of 11 modules, and each module in...

AI Technical Summary

Problems solved by technology

Although the author finally obtained a mutant strain with an increase in the production of Macrolactins by about 50%, the entire screening process was cumbersome and the reliability was not high, and the final screening efficiency was only 6.67%

To put it simply, using this strategy to breed excellent marine bacillus mainly includes three screening indicators: colony morphology, growth and metabolism. It can be seen that the use of this strategy to complete microbial breeding is intensive and inefficient, and because the colony morphology no longer changes The reason for this is that the breeding work can only achieve the first round of mutagenesis, which is not conducive to the further improvement of the metabolic performance of the strain

[0004] In summary, for marine Bacillus producing Macrolactins with unclear genetic background, the traditional microbial breeding strategy is an ideal means, but the inability to determine effective screening markers hinders the breeding process of this type of bacterial resources to a certain extent

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