Nanaerobes

Nanaerobes are organisms that are not able to grow in the presence of micromolar oxygen concentrations, but can grow and benefit if there are even lower nanomolar oxygen concentrations (for example, the bacterium Bacteroides fragilis ). Like other anaerobes , nanaerobes do not need oxygen to grow, i.e. Nanaerobes are facultative anaerobes . The advantage of growth in the presence of trace amounts (nanomolar concentrations) of oxygen requires a special oxygen respiratory chain , which is usually characteristic of microorganisms with microaerophilic respiration. Recent studies show that respiration in ultra-low oxygen concentrations is a very ancient process that preceded the emergence of oxygen photosynthesis .