Bacterial are very diverse and quite adaptable, but they still need certain factors in order to thrive. The physical requirements for bacterial growth include pH range, temperature, oxygen concentrations, moisture levels, hydrostatic pressure, osmotic pressure, and radiation levels.
When considering the pH level, bacteria are classified as either acidophiles (acid-loving), neutrophiles (neutral ph range), or alkaliphiles (alkali-loving). The one that causes disease in humans would be the neutrophiles, which have an ideal pH range of 5.4 to 8.0. There are exceptions, however, like Alcaligenes faecalis and Vibrio choleae, which are both alkaliphiles and can infect humans.
Bacteria can also be classified as to the temperature range in which it grows best. Psychrophiles are cold-loving and can live in temperatures from 0 20 C. Mesophiles are where the majority of bacteria fall, living between 25 40 C. Thermophiles are heat-loving and grow starting at 50 C all the way......
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