Question

2. Define fermentation. 3. What is purpose of the phenol red in the fermentation tube? 4. What is the function of the Durham tube in the fermentation tube? 5. What is the color of phenol red at an acid pH? 6. What is the function of ß-galactosidase?

Answer 1

Ans 2) Fermentation is the process in which a substance breaks down into a simpler substance.

Fermentation is way of producing ATP without oxygen is called fermentation. It is an anaerobic process.

Yeast and bacteria play a role in the fermentation , creating beer, wine, bread, yogurt and other foods.

There are 2 types of fermentation process- lactic acid fermentation and alcoholic fermentation.

Ans 3) In a phenol red fermentation , phenol red is used to determine if a bacterium can ferment a particular carbohydrate and identify the end products of that fermentation. Phenol is an indicator of ph . It changes colour from yellow to red as pH increases from 6.6 to 8.0.

Ans 4)Durham tube is used along with phenol red in fermentation , it is used in detection of gas produced in fermentation by microbes, this gas move up through the medium and produce bubbles in the Durham tube. The pH indicator phenol red is red at neutral pH and turns yellow at pH <6.8.

Ans 5) at an acidic ph , phenol red turns yellow in colour.

Ans 6) β-galactosidase is  also known as lactase, it  catalyzes the hydrolysis of Lactose into B-galactose + B-glucose through the breaking of a glycosidic bond.