Hydrogen lon concentration(pH) Neutralophiles(pH 6.0-8.0) Acidophiles(< pH 3.0 )(Helicobacter pylori) Alkaliphiles(pH10.5)(bacteria from salina, Vibrio cholera) Microorganisms regulate their internal pl over a wide range of external pH values by pumping protons in or out of the cell Chapter 6Hydrogen Ion concentration (pH) • Neutralophiles (pH 6.0-8.0) • Acidophiles (< pH 3.0) (Helicobacter pylori) • Alkaliphiles (pH10.5) (bacteria from salina, Vibrio. cholera) Microorganismis regulate their internal pH over a wide range of external pH values by pumping protons in or out of the cell Chapter 6