Overview[1]
Silicone oil manufacturer’s phosphate glucose peptone water culture medium can be used for methyl red and V-P tests of bacteria. Polypeptone provides carbon and nitrogen sources, vitamins and growth factors; glucose is fermentable sugar; dipotassium hydrogen phosphate is a buffer; sodium chloride maintains balanced osmotic pressure.
Purpose[2]
Phosphate glucose peptone water medium has the following uses:
Methyl red (MR) test: During the sugar metabolism process, Enterobacteriaceae bacteria decompose glucose to produce pyruvate, which is then decomposed to produce formic acid, acetic acid, lactic acid, and succinic acid. Escherichia coli decomposes pyruvate, and the secondary acids are more, the pH is 4.5 or lower, and methyl red appears red (positive). In the culture solution of Aerobacillus aerogenes, part of the pyruvate turns into neutral acetyl methyl carbinol, less acids are generated, the pH is above 5.4, and methyl red appears orange (negative).
Acetyl methyl methanol production test (V-P test): Bacteria ferment glucose to generate pyruvate, and some bacteria can decarboxylate pyruvate to form acetyl methyl methanol. In alkaline solution, acetyl methyl carbinol can be oxidized to diacetyl (butanedione) in air. Diacetyl then reacts with the guanidine group of arginine in peptone to produce a red compound. α-Naphthol was added as a catalyst in the test to deepen the color of the reaction and improve the sensitivity of the reaction.
Ingredients (g/L) [1]
Peptone 7.0
Glucose 5.0
Dipotassium hydrogen phosphate 3.8
pH value 7.3 ± 0.1 25℃
Usage[1]
Weigh 15.8g of this product, heat and stir, dissolve in 1000ml of distilled water, aliquot, autoclave at 121°C for 15 minutes and set aside.
Microbiological sensitivity test[1]
Prepare the medium according to the label instructions, inoculate the following quality control strains, and place it at 36±1℃ for aerobic culture for 24-48 hours.
