Looking at your results of your PRBlactose tubes what do you

Looking at your results of your PRB-lactose tubes, what do you expect to see in the Litmus Milk tubes for a) E.coli and b) Alcaligenes faecalis? Give a detailed explanation?

Solution

E.coli in PRB- lactose tubes , breaks down lactose and the solution turns pink The acid production , then the litmus milk will turn to pink . If the solution becomes alkaline then the litmus milk will become more blue. As the solution turns pink then there must be production of acid. Gas bubbles or cracks can be seen in the tubes , which indicates gas production. So E.coli breaks lactose and prouces acid and gas. Alcaligenes faecalis doesnot ferment lactose. It acts only on urea and uric acid and produces alkaline environment by increasing the pH. So in lactose tubes, there will not be any change in the tubes as it doesnot ferment lactose and not acid or alkali or gas production.