aérobies

Aérobies, or aerobes, are organisms that require oxygen for growth and metabolism. They rely on aerobic respiration in which oxygen serves as the final electron acceptor in the electron transport chain, yielding more ATP than anaerobic pathways. Most aerobes possess antioxidant defenses such as catalase and superoxide dismutase to neutralize reactive oxygen species generated during metabolism.

They are typically categorized by their oxygen requirements. Obligate aerobes cannot grow without oxygen. Microaerophiles require oxygen but at lower concentrations than are present in the atmosphere (usually around 2–10% O2). In contrast, facultative anaerobes (not strictly aerobes) can grow with or without oxygen but usually prefer oxygen because aerobic respiration is more energy-efficient. Aerotolerant organisms do not use oxygen but can survive exposure to it.

Habitat and role: Aerobes are common in soil, surface waters, and on body surfaces and mucous membranes. They play essential roles in decomposition, nutrient cycling, and environmental detoxification. Some aerobes are pathogens, such as Mycobacterium tuberculosis and Neisseria meningitidis, which rely on oxygen-rich environments of the host. Others, like Helicobacter pylori, are microaerophiles and inhabit niches with reduced oxygen.

Cultivation and detection: In the lab, aerobes are grown in oxygen-rich conditions, as oxygen is necessary for their growth. They are often studied for their metabolic versatility and resilience to oxidative stress.