Aerobic Metabolism

Synonyms

Aerobic respiration; Oxygen metabolism

Definition

Aerobic metabolism comprises the reduction of molecular oxygen as electron acceptor of aerobic respiration, its use as cosubstrate in the degradation of certain compounds, and reactions leading to the detoxification of partially reduced oxygen species.

Introduction

Life has evolved in the absence of molecular oxygen (see Chapter Early Earth ). Therefore, it is not surprising that basic metabolic pathways involved in growth and cell division (like DNA replication or protein synthesis) do not depend on the presence of molecular O₂. The evolution of the oxygen-producing (oxygenic) phototrophs dramatically changed the situation of living organisms. Molecular oxygen raised the redox potential of the environment and enabled microorganisms to respire with a much higher energy yield than before. Although oxygen is involved in a limited number of reactions only, its presence or absence has fundamental impact on biogeochemical processes.