👉 Archaeobacteria are single-celled bacteria that belong to the class Bacteroidetes, which includes Gram-negative and Gram-positive bacteria. They play a crucial role in archaea, an important kingdom of life on Earth, as they are essential for the functioning of cellular respiration, the breakdown of organic matter into simpler compounds, and the production of enzymes for various metabolic processes. Archaeobacteria have been found in diverse environments across the globe, ranging from freshwater sediments to marine habitats.