Journal Article

The abundance and variety of carbohydrate-active enzymes in the human gut microbiota

Henrissat, Bernard, Armougom, Fabrice, Gordon, Jeffrey I., Raoult, Didier, Kaoutari, Abdessamad El

2013

Overview

Key Points The human genome encodes only a small number of digestive glycoside hydrolases for the breakdown of sucrose, lactose and starch. Instead, the large diversity of complex polysaccharides in our diet is mainly digested by specialized enzymes encoded by the gut microbiome. A model human microbiome was constructed from 177 microbial genomes in proportions that approximate their representation in the healthy adult gut, and this mini-microbiome was used to evaluate the diversity of carbohydrate-active enzymes (CAZymes) in the gut microbiota. Gut bacteria from the phylum Bacteroidetes encode more CAZymes, and encode CAZymes from more families, than the other phyla represented in the model mini-microbiome. The large substrate range of these CAZymes is compatible with the diversity of the dietary plant cell wall polysaccharides that are presented to members of the microbiota. The human genome encodes very few enzymes involved in the digestion of complex polysaccharides, and this deficit is compensated for by the myriad of carbohydrate-active enzymes (CAZymes) encoded by members of the gut microbiome. In this Analysis article, Henrissat and colleagues characterize the CAZymes present in a representative human mini-microbiome. Descriptions of the microbial communities that live on and in the human body have progressed at a spectacular rate over the past 5 years, fuelled primarily by highly parallel DNA-sequencing technologies and associated advances in bioinformatics, and by the expectation that understanding how to manipulate the structure and functions of our microbiota will allow us to affect health and prevent or treat diseases. Among the myriad of genes that have been identified in the human gut microbiome, those that encode carbohydrate-active enzymes (CAZymes) are of particular interest, as these enzymes are required to digest most of our complex repertoire of dietary polysaccharides. In this Analysis article, we examine the carbohydrate-digestive capacity of a simplified but representative mini-microbiome in order to highlight the abundance and variety of bacterial CAZymes that are represented in the human gut microbiota.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 41 / analysis / Bacteria - classification / Bacteria - enzymology / Bacteria - genetics / Bioinformatics / Carbohydrates / Deoxyribonucleic acid / DNA / DNA sequencing / Enzymes / Fatty acids / Fermentation / Gastrointestinal Tract - enzymology / Gastrointestinal Tract - microbiology / Genetic aspects / Genomes / Glycoside Hydrolases - isolation & purification / Glycoside Hydrolases - metabolism / Glycosyltransferases - isolation & purification / Glycosyltransferases - metabolism / Humans / Infectious Diseases / Life Sciences / Medical Microbiology / Metabolism / Metagenome / Microbial activity / Microbiology / Microbiota / Microbiota (Symbiotic organisms) / Microorganisms / Nucleotide sequencing / Parasitology / Physiological aspects / Physiology / Polysaccharide-Lyases - isolation & purification / Polysaccharide-Lyases - metabolism / Polysaccharides / Saccharides / Small intestine / Virology