M17 agar
This bacterial growth medium was developed in 1971 for Lactococcus species isolated from milk products. It was originally called M16 medium,[1] but in 1975 Terzaghi and Sandine[2] added disodium-β-glycerophosphate to the medium as a buffer, and named the new growth medium M17 medium. It was later found that the addition of disodium-β-glycerophosphate inhibits the growth of many Lactobacillus species.[3]
Typical composition
Per 950 mL:[2]
- 5.0 g Pancreatic digest of casein
- 5.0 g Soy Peptone
- 5.0 g Beef extract
- 2.5 g Yeast extract
- 0.5 g Ascorbic acid
- 0.25 g Magnesium sulfate
- 10.0 g Disodium-β-glycerophosphate
- 11.0 g Agar
Preparation:
- 1. Heat with frequent agitation and boil for 1 minute to completely dissolve.
- 2. Autoclave at 121 °C for 15 minutes. Cool to 50 °C.
- 3. Add 50 ml filter sterilized 10% lactose solution and mix well (the lactose can be exchanged to other carbohydrates e.g. glucose, resulting in GM17 medium)
References
- ^ "The plating efficiency of bacteriophages of lactic streptococci". N.Z. J. Dairy Sci. Technol. 6: 166–171. 1971.
{{cite journal}}: Cite uses deprecated parameter|authors=(help) - ^ a b "Improved medium for lactic streptococci and their bacteriophages". Applied Microbiology. 29 (6): 807–813. 1975. PMC 187084. PMID 16350018.
{{cite journal}}: Cite uses deprecated parameter|authors=(help) - ^ "A note on the suppression of Lactobacillus bulgaricus in media containing β-glycerophosphate and application of the media to selective isolation of Streptococcus thermophilus from yoghurt". J. Soc. Dairy Technol. 30 (1): 28–30. 1977. doi:10.1111/j.1471-0307.1977.tb01162.x.
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