The Invention And Optimization Of Fermentation Condition Of Anti-Cryptocaryon Irritans Probiotics

As the seawater Ichthyophthirius,C.irritans belongs to a new branch of the Order Proreodonisa of Class Prostomatea,which is the Genus cryptocaryon of the Family Cryptocaryonidae.C.irritans is a kind of obligate parasites,distributed in tropical and subtropical waters,can infect Larimichthys crocea?Epinephelussp and most of the mariculture fishes,causing great harm.Immobilization antigen is one of various immunogenicity surface antigens in C.irritans.It can induce the fish to produce antibodies which can make C.irritans agglutinated or immobilizated.It is one of the candidate components of the anti-C.irritans vaccine.Bacillus subtilis is a kind of commonly used probiotics.The cell wall structure is simple,and the expression product can be directly secreted into the culture medium without secreting endotoxin,which is a good expression host strain..A strain of Escherichia coli that produces Immobilization antigen DT1749 has been constructed in the laboratory,on this basis,the Immobilization antigen DT1749 gene was cloned and ligated into the E.coli-B.subtilis shuttle plasmid pMA5 then transform to safe strain B.subtilis,construct B.subtilis engineered bacterium SCK6-DT1749 which can produces Immobilization antigen DT174 In this study.Using the number of surviving spores as an indicator,the culture conditions were optimized to obtain the optimal culture medium and culture conditions of SCK6-DT1749.After orthogonal test data analysis,the best carbon source of B.subtilis SCK6-DT1749 was bean cake powder.The best nitrogen source was corn pulp dry powder.The best culture temperature was 37?,and the optimal inoculum size was 6%.The best initial pH is 8,and the best incubation time is 72h.According to the optimization results of culture conditions,and combined with the actual industrial needs,the fermentation process and the fermentation plan of SCK6-DT1749 was designed after the factory visit to the factory.Based on the safety advantages of B.subtilis,this study solves many problems such as the secretion of endotoxin and the formation of inclusion bodies in Escherichia coli producing anti-inflammatory antigen in the previous experiments,and has completed the optimization of the culture conditions of engineering bacteria,and laid a foundation for the production of food-grade anti-C.irritans probiotics.