Is Bacillus subtilis lactose positive?

Is Bacillus subtilis lactose positive?

B. subtilis is able to complete glycolysis and the TCA (tricarboxylic acid) cycle because of its aerobic cellular respiration. B. subtilis can ferment glucose, sucrose, but not lactose.

What are the possible results of the litmus milk test?

Expected Results

• Acid pH: pink to red color.
• Alkaline pH: purplish- blue color.
• Reduction: white.
• Acid curd: hard curd with clear supernatant (whey)
• Digestion: Dissolution of clot with clear, grayish, watery fluid and a shrunken, insoluble pink clot.

Is Bacillus subtilis methyl red test?

The bacteria could only ferment glucose for acid production, but could not utilize lactose and maltose. The VP test for this bacteria was positive, while indole and methyl red tests were negative. Further analysis showed that these bacteria shared a homology up to 99.4% with Bacillus subtilis DQ198162.

Which enzymes are being tested in a litmus milk medium?

Some bacteria possess proteolytic enzyme caseinase and hydrolyze casein. Casein hydrolysis results in the release of large quantities of ammonia that makes the medium alkaline with a foul smell, the litmus turns into a purplish-blue.

What does the appearance of a white color in the litmus milk test mean?

Some bacteria act on the nitrogenous substrates in the milk releasing ammonia and yielding a purplish-blue color. Organisms that reduce litmus cause the oxygen to be removed, leaving a leuco (white) base. Proteolytic enzymes produced by certain organisms, hydrolyze milk proteins and result in clot formation.

Is Bacillus subtilis catalase-positive?

Bacillus subtilis (B. subtilis) is a Gram-positive, aerobic bacterium. It is rod-shaped and catalase-positive.

Which acid is present in milk?

lactic acid
The real acidity of milk is due to lactic acid.

What is the principle of litmus test in milk?

Principle of Litmus Milk Medium Test Milk is an excellent medium for the growth of microorganisms because it contains the milk protein casein, the sugar lactose, vitamins, minerals and water. Litmus, a pH indicator is incorporated in the medium for the detection of production of acid or alkali and oxidation- reduction activities.

What is the pH of milk in litmus?

Additionally, some organisms reduce litmus, in which case the medium becomes colorless in the bottom of the tube. Powdered skim milk (100 g), litmus (0.5 g), sodium sulphite (0.5 g), per 1000 mL, pH 6.8. Inoculate litmus milk medium with 4 drops of a 24-hour broth culture.

How many grams of sodium sulphite are in Litmus milk?

Powdered skim milk (100 g), litmus (0.5 g), sodium sulphite (0.5 g), per 1000 mL, pH 6.8. Inoculate litmus milk medium with 4 drops of a 24-hour broth culture.

What is the difference between milk and Litmus milk?

Milk is an excellent medium for the growth of microorganisms because it contains the milk protein casein, the sugar lactose, vitamins, minerals and water. Litmus milk is a milk-based medium used to distinguish between different species of bacteria.