CAZyO_GH

Glycoside hydrolases (GHs) are central to the carbon cycling across environments, yet accurate annotation of GHs in metagenomic datasets remains challenging due to the multidomain architecture of carbohydrate-active enzymes and the prevalence of unassembled short reads. Here, we present CAZyO_GH (CAZymes Open-source GH annotation), a curated reference database for the domain-specific identification of 135 protein domains spanning 99 GH families. Unlike existing tools such as dbCAN and GeneHunt, which rely on full-length protein sequences, CAZyO_GH focuses on individual GH domains, enabling robust annotation of both assembled and unassembled metagenomic data.We first validated CAZyO_GH by reanalyzing genomes listed in CAZy db, where predicted GH profiles closely matched reported values. Next, we used CAZyO_GH to analyze twelve human gut metagenomes and twelve newly sequenced soil microbiomes to reveal environment-specific GH repertoires. By accurately detecting catalytic domains independent of the genomic context, CAZyO_GH improves sensitivity and specificity in short-read metagenomic annotation. This framework provides a scalable and reproducible approach to investigate carbohydrate-active enzymes across ecosystems, advancing our capacity to characterize microbial functional potential in global carbon cycling.