Available Oxygen

Microorganisms can be classified according to their oxygen requirements necessary for growth and survival:

  • Obligate Aerobes: oxygen required
  • Facultative: grow in the presence or absence of oxygen
  • Microaerophilic: grow best at very low levels of oxygen
  • Aerotolerant Anaerobes: oxygen not required for growth but not harmful if present
  • Obligate Anaerobes: grow only in complete absence of oxygen; if present it can be lethal