Bacteria grow under optimal conditions of pH, temperature, and nutrients dependi

Question

Bacteria grow under optimal conditions of pH, temperature, and nutrients depending on the species’ metabolic requirements and adaptive responses. Some species have very strict and narrow growth conditions whereas others can grow in a wider range of stringency.

For this discussion assignment, select a bacterial species of your choice and prepare an initial post describing the optimal growth and media nutritional requirements in terms of the carbon and energy metabolic sources required for growth.

Also include a brief discussion about the type of media for optimal growth and how this might be used for identification of the bacterial species.

Please no handwritten or picture answers - only typed responses.

Explanation / Answer

Bacillus subtilis: It is Gram positive motile bacteria, catalase +, oxidase +, endospore forming, facultative anaerobe, ferments glucose, sucrose, mannitol, citrate +, nitrate reductase +, and Voges-Proskauer +. It is commonly found in grass and hence, is called grass bacteria or hay bacteria.

The bacteria can grow at temperature ranges from 15 degree to 50 degree celcius. Optimum growth temperature is 28-30 degree C, and grows best at 37 degree C. They grow in any simple growth medium. Luria-Bertani broth is used to culture the bacteria, with the following components:

Tryptone-10 g

Yeast extract-5 g

NaCl-10 g

H2O (dist) - 1 L

To induce sporulation, they require salts like KCl, CaCl2, MgSO4, and FeSO4. The bacteria can grow on simple sugars. Generally, glucose is the ultimate source of carbon for the bacteria. However, they can make energy (ATP) through buatenediol fermentation, nitrate ammonification, and lactate fermentation. During aerobic respiration, the organism obtains energy through complete oxidation of the carbon source, through ETC. The organism can perform fermentation without external electron acceptors.

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