Milbemycin strain with high-yield and its application

Abstract

A strain for high-yield production of milbemycin and use thereof is disclosed. In the present invention, an original strain MI-W1-2017001 is subjected to mutation breeding by an atmospheric and room temperature plasma mutation method to obtain a high-yield strain HZMRYB-5. The fermentation level of the strain is improved by about 70% compared with the original strain, and the fermentation level is further improved by about 35% through optimization of a fermentation process and a formulation, so that the fermentation cost of the product is further reduced, and requirements for the industrial fermentation level are met. On the basis of optimizing the fermentation process, the ratio of A3 and A4 in a fermentation liquid is nearly 3:7 through mixed fermentation of the strain MI-W1-2017001 and the strain HZMRYB-5, so that market demands are greatly met, the process steps of separation, purification and then mixing are reduced.