What type of bacteria continue metabolism at low pH?

What type of bacteria continue metabolism at low pH?

• A. Non-acidogenic
• B. Acidogenic and aciduric
• C. Alkaliphilic
• D. Aerobic

Answer: (B)

The key idea here is that metabolism can continue in acidic environments only if the bacteria are acid-tolerant and often acid-producing. Acidogenic organisms ferment sugars to produce acids, which lowers the surrounding pH, while aciduric organisms withstand those acidic conditions and keep functioning despite the low pH. Together, these traits allow ongoing metabolic activity even when the environment becomes acidic. Non-acidogenic producers don’t generate acid and may struggle as pH drops; alkaliphilic bacteria are adapted to high pH and would be stressed by low pH; aerobic bacteria’ defining feature is using oxygen, not tolerating acidity, so their ability to metabolize at low pH isn’t guaranteed. Hence, acidogenic and aciduric bacteria best explain continued metabolism at low pH.

The key idea here is that metabolism can continue in acidic environments only if the bacteria are acid-tolerant and often acid-producing. Acidogenic organisms ferment sugars to produce acids, which lowers the surrounding pH, while aciduric organisms withstand those acidic conditions and keep functioning despite the low pH. Together, these traits allow ongoing metabolic activity even when the environment becomes acidic. Non-acidogenic producers don’t generate acid and may struggle as pH drops; alkaliphilic bacteria are adapted to high pH and would be stressed by low pH; aerobic bacteria’ defining feature is using oxygen, not tolerating acidity, so their ability to metabolize at low pH isn’t guaranteed. Hence, acidogenic and aciduric bacteria best explain continued metabolism at low pH.