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🦠microbiology review

Optimum oxygen concentration

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Optimum oxygen concentration is the specific level of oxygen that supports the best possible growth and metabolic activity for a particular microorganism. This concentration varies among different types of microbes based on their oxygen requirements.

5 Must Know Facts For Your Next Test

  1. Different microorganisms have varying optimum oxygen concentrations, classified as obligate aerobes, obligate anaerobes, facultative anaerobes, microaerophiles, and aerotolerant anaerobes.
  2. Obligate aerobes require an environment with high levels of oxygen to grow.
  3. Obligate anaerobes cannot tolerate oxygen and grow best in its absence.
  4. Facultative anaerobes can grow in both the presence and absence of oxygen but prefer environments with oxygen for optimal growth.
  5. Microaerophiles need low levels of oxygen (lower than atmospheric levels) for growth, whereas aerotolerant anaerobes do not require oxygen but can tolerate its presence.

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