Biological Characteristics Of Bacillus Subtilis Bacteriophage TXp1and Breeding Of Resistant Strains

Inosine is an important nucleoside compounds, its main production methods is microbialfermentation，and Bacillus subtilis is used for the production of bacteria in the fermentation.Inosine fermentation process by the Bacillus subtilis bacteriophage infection was caused dueto cell lysis then fermentation failed to bring substantial economic losses fermentation.Breeding resistant strains of phage strains genetic characteristics changed radically, so thatsites of host bacteria are adsorbed phage change is an important means to prevent phageinfection. Author brothed bacteriophages from inosine fermentation,studied the biologicalcharacteristics of phages and filtered by natural and UV mutagenesis to obtain anti-phagestrains. This paper offers available to prevent phage contamination rotation in the productionof bacteria strains for inosine fermentation.(1) Through the double plate method, yielding strain of phage contamination fromthe fermentation broth, and numbered TXp1. The phage is potent phage. And titer of thephage can reach4.9×1010PFU/mL.(2) According to the analysis of transmission electron microscopy and DNAelectrophoresis, phage TXp1was tadpole-like, and head is the regular polyhedron structure,diameter64±2nm, there is an obvious short tail, about25±1nm. Phage nucleic acid can bedecomposed Dnase I, as a double-stranded DNA bacteriophage genome size is about20kb.According virus classification eighth report of the International Committee on Taxonomy ofViruses, the phage belonged to Caudovirales, Podoviridae, φ29phage.(3) This research studied biological characteristics of the phage TXp1: bacteriophageTXp1population has a wide host range of Bacillus insensitive other populations, to infect thehost with specificity; relatively unstable to heat, at50℃,60℃temperature within1h there is still some activity within a short time under80℃condition rapidly inactivated;phage TXp1of acid has a strong ability to adapt in the pH range of3.0to11.0were someability to survive, while relatively stable between pH6.0~7.0; phage TXp1strong ultravioletdestruction,8min after irradiation has been basically phage inactivation. Best multiplicity ofinfection (MOI) of0.1~1.0; one step growth curve showed an incubation period of40min,the cleavage of the80min, the amount of cleavage of99±3PFU/cell; it has the highersurvival rate when it was saved under the conditions4℃or-80℃.(4) Three anti-phage strains of Bacillus subtilis T105have got B. subtilisT105ZX-71、 B. subtilis T105UV-10and B. subtilis B. subtilis T105UV-103throughspontaneous mutation and UV mutation, and against lysogenic phage strains and geneticstability testing were identified. Fermentation experiments show two strains of phage resistantinosine fermentation were capable of producing up to9.88g/L、12.03g/L and10.58g/L, canbe reached85.69%、104.34%and91.79%of the production strain B. subtilis T105fermentation capacity..