Sdudies On Mutation Method And Inhibitory Activity Of Culture Broth Of Photorhabdus Luminescens

Photorhabdus is a genus of gram-negative Enterobacteriacae that is pathgenic to insect larvae while also maintaining a mutualistic relationship with nematodes from the family Heterorhabditis, where the bacteria occupy the gut of the infective juvenile stage of the nematode. The study of comprehensive inhibitory activity and chemical mutation model and breeding of high - yield inhibitory substance of Photorhabdus luminescens 1029 were introduced in this paper. Results as follows:1. The toxicity test of Photorhabdus luminescens 1029 was studied against 10 species of pathogens through growth rate method and inhibitory cirle method. The results showed that the Photorhabdus luminescens 1029 had inhibition to the 10 species of pathogens, especially to Phomopsis sp., Peronophythora litchi, Clavibacter sepedonicum and Ralstonia solanacearum. We could conclude that it had a wide-range inhibition.2. The physical and chemical properties showed that the antibiotic substance from Photorhabdus luminescens 1029 culture broth were relatively complex. It had not only durable high temperature and ultraviolet radiation elements but also sensible elements to them. The culture broth had highest antibiotic activity at pH 7-8.3. Active component which was produced by Photorhabdus luminescens 1029 was isolated by silica gel column chromatography, we got one active component F-1.F-1 was identified as the 2-isopropyl-5-(2-phenylethenyl)-benzene-1,3-diol through MS and ~1HNMR spectra. The Active component was same to the active component from Photorhabdus luminescens HK.4. The initial strain Photorhabdus luminescens 1029 was treated by mean of NTG mutagenesis. one high-yidld mutant strain was got, which inhibitory activity increased by 12.82%. Successively cultured five times in the medium, heredity character of it was stable. so this mutant method adapt to industrial breeding.