<Li> Dissolved oxygen increases the redox potential of a solution, and high redox potential inhibits the growth of some obligate anaerobes . For example, methanogens grow at a redox potential lower than - 0.3 V . </Li> <Li> Sulfide is an essential component of some enzymes, and molecular oxygen oxidizes this to form disulfide, thus inactivating certain enzymes (e.g. nitrogenase). Organisms may not be able to grow with these essential enzymes deactivated . </Li> <Li> Growth may be inhibited due to a lack of reducing equivalents for biosynthesis, because electrons are exhausted in reducing oxygen . </Li> <P> Obligate anaerobes metabolise energy by anaerobic respiration or fermentation . In aerobic respiration, the pyruvate generated from glycolysis is converted to acetyl - CoA . This is then broken down via the TCA cycle and electron transport chain . Anaerobic respiration differs from aerobic respiration in that it uses an electron acceptor other than oxygen in the electron transport chain . Examples of alternative electron acceptors include sulfate, nitrate, iron, manganese, mercury, and carbon monoxide . </P>

Obligate aerobes are poisoned by the presence of co2