What is Generation time in Microbiology?

Generation time is the
time required for a bacterial cell to grow and divide or the time required for
a population of cells to double in number.

The generation time of
*E.coli *in glucose salts is 17 minutes. That means if initial number is
10, to become 20, 17 minutes is required.

Let us work out a
problem.

?
if 100 bacteria multiply to produce a population of 3.28 × 10^{6} cells
in 7 hours, then What is the generation time of this bacterium?

**Generation
time (min/generation) = 60 minutes X number of hours**

**
number
of generations**

**Step
1: Find out the number of **

**generations.**

No.
of generations=__ log No. of cells at the end of reproduction- log No of cells
initially__

log 2

Log
2 is used in the formula as each bacterial cell produces 2 offspring on each
division.

**Step
2: Substitute the **

**values.**

Final
No. of cells at the end of reproduction=3.28 × 10^{6} cells

Initial
No. of cells =100

No.
of generations=log (3.28 x 10^{6}) - log (100)/ log2

=6.515-2/0.30102

=4.515/0.30102

=14.99
=15 generations

Now
we know the number of generations.

**Step
3 Find out generation time by substituting the **

**values.**

No.
of hours: 7 hours (given in the question)

No.
of generations: 15 hours (from the previous step)

**Generation
time (min/generation) = 60 minutes X number of hours**

**
number
of generations**

**Generation
time (min/gen) = 60 minx7hrs =28 min/generation**

**
15**

Thank you