<em>Obligate anaerobes are microbes that can only survive in oxygen-deficient environments. They are killed by the normal atmospheric level of oxygen and will only thrive in environments whose oxygen levels are lower than that of normal atmospheric level. </em>
Obligate bacteria such as <em>Clostridium botulinum </em>obtain their energy through <u>anaerobic respiration processes such as fermentation and anaerobic respiration.</u> During this process of fermentation, the lactic acid pathway is mostly used but other fermentation pathways such as propionic acid, mixed acid, acetogenesis, and methanogenesis pathways can be used.
