The phylum Bacteroidetes is a diverse group of bacteria found in various environments, including the gastrointestinal tract of animals, soils, oceans, and freshwater. They are known for their ability to degrade complex organic matter, particularly polysaccharides. Recent genomic studies have revealed a wide range of carbohydrate-active enzymes in Bacteroidetes, enabling them to utilize various substrates from plants, algae, and animals. Comparative genomics show that specific polysaccharide utilization loci are shared among distantly related Bacteroidetes species, both in environmental and gut-associated populations. Bacteroidetes genomes are highly plastic, often undergoing genetic rearrangements, gene duplications, and lateral gene transfers (LGT), which may have contributed to their adaptation to different ecological niches. The diet significantly influences the composition of the intestinal microbiota. The consumption of food can transfer environmental bacteria to the gut, where they may contribute to the degradation of refractory substrates in the diet. Understanding the genetic connections between food-associated environmental species and intestinal microbial communities is crucial for understanding the origin and evolution of Bacteroidetes as symbionts. The increasing consumption of hygienic and processed foods may reduce the diversity of environmental genes in the microbiota, potentially affecting health. Bacteroidetes are found in various habitats, including the gut, soil, and marine environments. They play a key role in the degradation of complex organic matter, especially polysaccharides and proteins. In the gut, they contribute to the breakdown of dietary polysaccharides, which are important for the host's energy supply. They also produce short-chain fatty acids that are reabsorbed by the host, aiding in energy acquisition from otherwise indigestible carbohydrates. In marine environments, Bacteroidetes are abundant and often found on surfaces, in biofilms, and in sediments. They are involved in the degradation of organic matter, including polysaccharides and proteins. In freshwater environments, they are also abundant and play a role in the degradation of organic matter. In soil, they are found in various locations and contribute to the breakdown of organic matter. Some members of the Bacteroidetes phylum can be pathogenic, causing infections in humans and animals. They can cause diseases such as periodontal disease and caries. The pathogenicity of Bacteroidetes is partly due to their ability to produce enzymes that degrade host cellular components. The diversity of polysaccharides that Bacteroidetes can degrade reflects their ability to adapt to different environments. They have access to a wide range of carbon sources, including polysaccharides from plants, algae, and animals. The genomes of Bacteroidetes species are rich in carbohydrate-active enzymes (CAZymes), which are essential for their ability to degrade complex glycans. Genomic studies have shown that Bacteroidetes genomes are highly plastic, with frequent genetic rearrangements, gene duplications, and lateral geneThe phylum Bacteroidetes is a diverse group of bacteria found in various environments, including the gastrointestinal tract of animals, soils, oceans, and freshwater. They are known for their ability to degrade complex organic matter, particularly polysaccharides. Recent genomic studies have revealed a wide range of carbohydrate-active enzymes in Bacteroidetes, enabling them to utilize various substrates from plants, algae, and animals. Comparative genomics show that specific polysaccharide utilization loci are shared among distantly related Bacteroidetes species, both in environmental and gut-associated populations. Bacteroidetes genomes are highly plastic, often undergoing genetic rearrangements, gene duplications, and lateral gene transfers (LGT), which may have contributed to their adaptation to different ecological niches. The diet significantly influences the composition of the intestinal microbiota. The consumption of food can transfer environmental bacteria to the gut, where they may contribute to the degradation of refractory substrates in the diet. Understanding the genetic connections between food-associated environmental species and intestinal microbial communities is crucial for understanding the origin and evolution of Bacteroidetes as symbionts. The increasing consumption of hygienic and processed foods may reduce the diversity of environmental genes in the microbiota, potentially affecting health. Bacteroidetes are found in various habitats, including the gut, soil, and marine environments. They play a key role in the degradation of complex organic matter, especially polysaccharides and proteins. In the gut, they contribute to the breakdown of dietary polysaccharides, which are important for the host's energy supply. They also produce short-chain fatty acids that are reabsorbed by the host, aiding in energy acquisition from otherwise indigestible carbohydrates. In marine environments, Bacteroidetes are abundant and often found on surfaces, in biofilms, and in sediments. They are involved in the degradation of organic matter, including polysaccharides and proteins. In freshwater environments, they are also abundant and play a role in the degradation of organic matter. In soil, they are found in various locations and contribute to the breakdown of organic matter. Some members of the Bacteroidetes phylum can be pathogenic, causing infections in humans and animals. They can cause diseases such as periodontal disease and caries. The pathogenicity of Bacteroidetes is partly due to their ability to produce enzymes that degrade host cellular components. The diversity of polysaccharides that Bacteroidetes can degrade reflects their ability to adapt to different environments. They have access to a wide range of carbon sources, including polysaccharides from plants, algae, and animals. The genomes of Bacteroidetes species are rich in carbohydrate-active enzymes (CAZymes), which are essential for their ability to degrade complex glycans. Genomic studies have shown that Bacteroidetes genomes are highly plastic, with frequent genetic rearrangements, gene duplications, and lateral gene