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When using the phenol red carbohydrate broth fermentation test at what pH is the pH indicator yellow?
Wiki User
∙ 14y ago
below 6.8
Wiki User
∙ 14y ago
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What does yellow indicate on the ph scale?
It depends on what indicator you are using. Yellow with the bromothymol blue indicator is acidic, yellow with the methyl orange indicator is basic, yellow with the phenol red indicator is acidic and yellow with the universal indicator is acidic.
What is the durham fermentation tube?
A Durham fermentation tube is a test tube that has a second inverted tube inside used to capture fermented gas (CO2) byproducts of bacteria. Typically the tube has a pH indicator in it, like phenol red, that will change color when acid is present (in this case to yellow). Gases are trapped inside the Durham tube, while the indicator shows the production of acid. Low pH is caused by Lactic Acid.
What phenol is phenol used in?
Phenol is used in various applications such as a disinfectant in household cleaners and mouthwash, in chemical peels for skin treatments, as food and cosmetic preservatives, and in the production of carbolic soap. it's also used for the permanent treatment of ingrown toes and fingernails, a procedure known as chemical matrixectomy. moreover, it is utilized in many industries, such as plastic, resin, and cosmetics
What is the purpose of TSI agar?
TSI means Triple sugar Iron. To identify gram negative entric bacilli on the basis od carbohydrate fermentation and hydrogen sulphide production. The TSI agar contains three sugars dextrose, lactose and sucrose and indicator phenol red. Carbohydrate fermentation is idicated by the release of gas and change in colour from red to yellow. Hydrogen sulphide production is seen blackening of butt. For the detection of organisms that only ferment dextrose, the dextrose concentration is one-tenth the concentration of lactose or sucrose. The small amount of acid produced in the slant of the tube during dextrose fermentation oxidizes rapidly, causing the medium to remain red or revert to an alkaline pH. In contrast, the acid reaction (yellow) is maintained in the butt of the tube because it is under lower oxygen tension. Once the dextrose is depleted the organism starts to utilise lactose or sucrose.
How do mannitol-salt agar tests work?
Mannitol salt agar supports growth of organisms that can grow in a high salt concentration, particularly Staphylococcus species and halophiles. The phenol red pH indicator in the agar will also let you know whether or not the bacterium you streaked ferments mannitol by changing to a yellow color if fermentation has occured.
Explain the purpose of the phenol red in the medium?
To determine if a bacterium can ferment a particular carbohydrate and determine the end products of that fermentation
Acid end products change pH?
Acid End Products from carbohydrate fermentation turn the pH indicator phenol red from red (alkaline) to yellow (acid).
Phenol Red is used in carbohydrate fermentation testing because?
Phenol Red is used in this testing because it offers a mid-range pH balance. The color changes from red to yellow when the test is complete.
What does yellow indicate on the ph scale?
It depends on what indicator you are using. Yellow with the bromothymol blue indicator is acidic, yellow with the methyl orange indicator is basic, yellow with the phenol red indicator is acidic and yellow with the universal indicator is acidic.
Purpose of the phenol red in the medium?
Phenol red acts as the pH indicator. Turning yellow as the ph lowers (acidic environments) and deep red when the ph is high (alkaline environment)
What is the durham fermentation tube?
A Durham fermentation tube is a test tube that has a second inverted tube inside used to capture fermented gas (CO2) byproducts of bacteria. Typically the tube has a pH indicator in it, like phenol red, that will change color when acid is present (in this case to yellow). Gases are trapped inside the Durham tube, while the indicator shows the production of acid. Low pH is caused by Lactic Acid.
What does is mean when phenol red turns yellow in a experiment?
phenol red turns yellow because it reacts to carbonic acid, which is a product of carbon dioxide mixing with H2O, or water. Phenol red is a Ph indicator, but not a very good one, so it reacts to strong acids (yellow orange) and strong bases (pink) hope this helped!
What colour phenol red indicator in dilute sulphuric acid?
below pH 6.8above pH 8.26.8 yellow↔8.2 purple
What phenol is phenol used in?
Phenol is used in various applications such as a disinfectant in household cleaners and mouthwash, in chemical peels for skin treatments, as food and cosmetic preservatives, and in the production of carbolic soap. it's also used for the permanent treatment of ingrown toes and fingernails, a procedure known as chemical matrixectomy. moreover, it is utilized in many industries, such as plastic, resin, and cosmetics
HOW IS IT POSSIBLE FOR AN ORGANISM TO BE POSITIVE FOR GLUCOSE USE IN A PHENOL RED TEST BUT NEGATIVE IN THE METHYL RED TEST?
Methyl red differs from Phenolred (which is used in the fermentation test and the MSA plates) in that it is yellow at pH 6.2 and above and red at pH 4.4 and below. Phenol red turns yellow below a pH of 6.8. If you get a positive with methyl red and a negative with phenol red, the pH has to be between 6.7 and 6.1.
What would make phenol change to pink or yellow?
after preparing the white phenol, addition of any color shall turn to the respective color. Like lemon salt shall turn the phenol in to yellow in colour.
What is the purpose of TSI agar?
TSI means Triple sugar Iron. To identify gram negative entric bacilli on the basis od carbohydrate fermentation and hydrogen sulphide production. The TSI agar contains three sugars dextrose, lactose and sucrose and indicator phenol red. Carbohydrate fermentation is idicated by the release of gas and change in colour from red to yellow. Hydrogen sulphide production is seen blackening of butt. For the detection of organisms that only ferment dextrose, the dextrose concentration is one-tenth the concentration of lactose or sucrose. The small amount of acid produced in the slant of the tube during dextrose fermentation oxidizes rapidly, causing the medium to remain red or revert to an alkaline pH. In contrast, the acid reaction (yellow) is maintained in the butt of the tube because it is under lower oxygen tension. Once the dextrose is depleted the organism starts to utilise lactose or sucrose.
