ABSTRACT
OBJECTIVE: Phage infection could seriously influence cell growth and metabolism in the fermentation of 1,3-propanediol from glycerol by Klebsiella pneumoniae. Isolation of the Klebsiella pneumoniae phage and research on its physiological characteristics would be of great significance. METHODS: A K. pneumoniae phage was isolated by using Adams double plate method from the infected fermentation broth of 1,3-propanediol. After the electron microscope observation, the genome of the phage was extracted and its size was identified with restriction enzyme analysis. The physiological characteristics of the phage were also tested, such as the optimal multiplicity of infection, the one-step growth curves and the sensitivity to temperature, pH, UV light and chloroform. And the phage infected fermentation was carried out and compared with normal fermentation. RESULTS: The phage had an isometric polyhedral head (about 60 nm -70 nm in diameter) and a long noncontractile tail (about 160 nm long). The nucleic acid could be cut off by dsDNA restriction enzyme EcoR I or Hind III and its complete size was about 42 kb. It was sensitive to high temperature and UV light, insensitive to chloroform. The optimal multiplicity of infection for the phage was 1, the latent phase and rise phase were both 50 min, and the burst size was 343. Compared with the normal fed-batch fermentation of 1,3-propanediol, the phage infected fermentation indicated that cell growth was delayed about 8 h and metabolic flow was changed to organic acid (e. g. lactic acid) pathway. CONCLUSION: The phage was a non-envelop long-tailed phage, and could change the metabolism of the 1,3-propanediol fermentation from glycerol by Klebsiella pneumoniae. This work would be helpful for prevention and controlling of phage infection during the 1,3-propanediol fermentation.
