Differential Broth for Lactic Streptococci

[所属分类:培养基配方] [发布时间:2020-6-19] [发布人:] [阅读次数:] [返回]

山东拓普生物工程有限公司

Shandong Tuopu Biol-Engineering Co.,Ltd

Differential Broth for Lactic Streptococci

培养基配方
Composition per liter:
Sodium citrate............................................................20.0g
Arginine...................................................................5.0g
Pancreatic digest of casein................................................5.0g
Yeast extract..............................................................5.0g
K2HPO4 ....................................................................1.0g
Bromcresol Purple.........................................................0.02g
Skim milk (11% solution).................................................35.0mL
pH 6.2 ± 0.2 at 25°C
Preparation of Medium:  Add components, except skim milk solu-
tion, to distilled/deionized water and bring volume to 800.0mL. Mix
thoroughly. Add 35.0mL of skim milk solution. Bring volume to 1.0L
with distilled/deionized water. Place medium in a steam bath for 15
min. Cool to 25°C. Adjust pH to 6.2. Distribute 7.0mL volumes into
screw-capped tubes that contain an inverted Durham tube. Autoclave
for 15 min at 15 psi pressure–121°C. Allow autoclave to cool below
70°C before opening door.
Use: For the cultivation and differentiation of Lactobacillus lactis, Lac-
tobacillus lactis subspecies cremoris, and Lactobacillus lactis subspe-
cies diacetylactis. Lactose-fermenting bacteria such as Lactobacillus
lactis subspecies cremoris turn the medium yellow. Arginine-utilizing
bacteria such as Lactobacillus lactis initially turn the medium yellow but
then turn it back to violet. Citrate-utilizing bacteria such as Lactobacillus
lactis subspecies diacetylactis turn the medium violet and produce CO2
that is trapped as a bubble in the Durham tube.