You just started working in a microbiology lab. You investigate a sauerkraut making facility and there is a new bacterial species growing in the acidic sauerkraut mixture. This new species must be a....
The answer is E. Acidophile.
Acidophiles grow best at pH levels close to zero which are very acidic. The acidic environment is conducive to the fermentation of cabbage allowing it to become sauerkraut. Acidophiles have the unique capability to survive in a highly acidic environment because they eject hydrogen ions from the cell before damage can occur to the cell's DNA.
Reviewing the other choices:
A. Thermophiles - prefer pH of 6.5-7.5, grow in temperatures that most microorganisms would die in 122 F - 140 F (50 C- 60 C).
B. Mesophiles - most common microbes, found in soil and water, prefer pH of 6.5-7.5 and temps between 25 C - 40 C.
C. Halophiles - prefer high salinity, 10x higher than seawater, found in areas like the Dead Sea, Great Salt Lake.
D. Psychrophiles - prefer temps of 15 C and generally located in the Arctic/ Antarctic Oceans.