require oxygen

use oxygen as a final electron acceptor

eg: Staphylococcus aureus

require limited amount of oxygen

The excess oxygen block activities of oxidativeenzymes > cause death

eg: Helicobacter pylori

require absence of oxygen

use other molecules as final electron acceptor

metabolise energy by anaerobic respiration orfermentation

eg: Clostridium tetani

can grow in present / absence of oxygen

prefer use oxygen for growth

In oxygenpoor environment, cellularrespiration may occur anaerobically, utilizingsuch compounds :

use sulfate & nitrates as final electron accertor

eg: Escherichia coli

not use oxygen for growth

not killed by the presence of oxygen

not use oxygen as final electron acceptor

produce catalase or superoxide dismutase

fermentative organisms

eg: Lactobacillus