Bacteriophages of l-Glutamic Acid-Producing Bacteria

Some of the characteristics of the four phages, P 465 (group I), P 468 II (group II), Ap 85 III (group III) and P 4 (group IV), of Brevibacterium lacto fermentum, i.e., stability in salt solution, thermal and pH stabilities, inactivation by ultraviolet irradiation, stability on air-drying, and lytic characteristics of infected cells, are descrided. We have observed differences in these physico-chemical characteristics among these four phages selected from the respective serological groups. An addition of protein such as casein to diluent at a 0.01 ~ 1% concentration increased remarkably the stabilities on shaking of these phages except Ap 85 III. There were great differences in stabilities on air-drying among the four phages. Phage P 61 (gropu I) which was isolated from the first abnormal fermentation broth showed the lowest stability in the dry state, while phages, P 468 II and Ap 85 III, were very stable and were not inactivated by the relative humidity of 10% at 30°C, for the period of five months. In general, Ар-series phages isolated from air-borne particles at fermentation factory can be distinguished from the other P-series phages which were isolated from abnormal fermentation broth, by their considerably high resistance to drying.