Bioreactors

Q & A of Bacterial Growth Kinetics (Basics)

What is Bacterial Growth?

Bacterial growth is increase in bacterial size and number (population).

What factors affect the bacterial growth?

The Bacterial growth is affected by the nutritional supply/ availability and physical factors like temperature, pH, humidity and gases (oxygen and carbon dioxide)

What is Bacterial Growth Kinetics?

It is the sub branch of Microbiology that deals with the study of rate of microbial growth in given media.

Why do we study the bacterial Growth Kinetics?

The bacterial growth kinetic study allow us to describe microbial growth

A kinetic model that describes microbial growth, product formation and substrate consumption and the experimental data were fitted with modified logistic equation.

What is the difference between cell concentration and cell density?

The Cell concentration means number of bacterial per unit volume whereas, the bacterial density is defined as dry weight of bacterial cells per unit volume of culture.

What is generation time?

It is the time taken by the bacteria to double its population. And it varies from bacterial species to species. It is also affected the availability of nutrients and physical conditions.

What is specific growth rate constant?

It indicates the rate or speed of microbial growth occurring in the culture flask in specific conditions like particular temperature, pH or any concentration of essential nutrient.

How bacterial growth is represented mathematically?

The bacteria that multiplies by binary fission produces two daughter cells. Hence, the bacterial population increases like 2, 4, 8, 16, 32…. it goes on. We can also write the same as 21 , 22, 24, 28 ……The superscript indicates the number of generation. In general, it can be represented as 2n.

What is endogenous metabolism in microbial growth curve?

When there is scarcity of nutrient and energy, the multiplying bacteria feed on dead and lysed bacterial cells. When bacteria grows on the dead cells, it is called as endogenous metabolism. Such growth and metabolism pattern is observed in Stationary phase.

Is kinetics remains the same for all the bacterial growth curves phases?

No, the kinetics for lag, log, stationary and death phase is different and hence we have different equations for respective one. This will be explained in the next article.

References-

http://rpdata.caltech.edu/courses/Physiology%20Matlab%202014/Paper

https://www.intechopen.com/books/cell-growth/kinetic-studies-on-cell-growth

https://www.cs.montana.edu/webworks/projects/stevesbook/contents/chapters/chapter002/section002/black/page001.html

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