Bacteria and Archaea - Microbial Growth

levels of microbial growth

• individual cell level

• the population level

aerobes

• require/use oxygen

• have a high ATP yield

• Oxygen at end of ETC (final electron acceptor)

obligate anaerobes

• do not require require or cannot tolerate oxygen

• they do not have the enzymes required to “deal with” oxygen

• instead use other electron acceptors at the end of the ETC

• results in less ATP

facultative anaerobes

• can use oxygen when it is present (produces more ATP)

• but can survive without oxygen

microaerophiles

• Require a specifically low oxygen concentration

• too high oxygen levels are toxic due to limited enzymes available that are critical in processing oxygen

aerotolerant anaerobes

• Do not use oxygen, but do have enzymes to handle it (not harmed by oxygen)

• Ferment

• ancestral trait, some genes lacking