Experiment physical factors : Temperature & pH




Hi and hello guys, so today experiment we going to do experiment about physical factors which are temperature and pH. All bacteria can be classified into one of three major groups,depending on their temperature requirements.


 Psychrophiles: Bacteria species that will grow within a temperature range of -5°C to 20° C . They will grow within 0° C and 5° C. 

 Mesophiles : Bacterial species that will grow within a temperature range of 20°C to 45° C.


Thermophiles : Bacterial species that will grow at 35° C and above. Two group of thermophile that exists. Facultative thermophiles and obligate thermophiles.

in 37° C

in 20° C


in 4° C

in 60° C



pH. Certain organisms can grow at extremes of the pH scale, generalities can be made. The specific range for bacteria is between 4 and 9, with the optimum being 6.5 to 7.5. Fungi prefer an acidic environment, with optimum activities at a pH of 4 to 6. The neutral pH is 7. 


The spectrophotometer was used to record the reading of absorbance. There are 3 cultures that we used, which are E.coli , A. faecalis and S. cerevisiae in pH of 3 , 6 , 7, and 9.



That all that I can share. I will update more later. Goodbye :)









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