ISOLATION AND IDENTIFICATION OF TWO SUBSPECIES OF PROPIONIBACTERIUM FREUDENREICHII
费氏丙酸杆菌两个亚种的分离与鉴定

Three strains Propionibacterium (PTC-1, PTC-2 and PTC-3) were isolated fromdifferent dairy products by using Hungate anaerobic technology. Cells are pleomorphic rods,Gram-positive, non-sporing, nonmotile. Colonies in PYG deep agar of roll tubes are lenticular,white, yellow to ho. Acids are produced from eight kinds of carbohydrates e. g. glucose,lactose and so on. Fermentation products of glucose include large amounts of propionic andacetic acid, and lesser amounts of isobutyric, succinic acids and carbon dioxide. They areanaerobic to aerotolerant. G C content of the DNA of PTC-1 is 67.8 mol% (Tm). Thecharacters of three strains are close, a little different lie in the natures of nitrate areduce andmilk curd. They all were determined as; PTC-1 and PTC-2 are identical species, Propionibacterium freudenreichii subsp. freudenreichii (AS 1.2128 and AS 1.2129 respectively), PTC-3 isP.freudenreichii subsp. shermanii (AS 1.2130). They are important strains in the use of thefermentation and food industries in group of classical propionibacteria.