Mining and Characterization of Carbohydrate-Active Enzymes in MAGs from Animal Gut Microbes

Background: CAZymes mediate carbohydrate catabolism in animals and are critical for supporting animal growth, development, metabolism and production performance. This study aimed to explore the gut microbial CAZyme repertoire of humans and multiple animal species and identify novel and efficient CAZymes. Methods: A total of 100,090 MAGs from humans and 10 animal species were collected for CAZyme annotation. PULpy was used to annotates PULs encoded by the Bacteroides. DeepFRI annotation combined with molecular docking was used to screen novel CAZymes. Prokaryotic expression was further performed to obtain the target enzyme and verify its substrate-degrading activity. Results: We annotated 8,747,365 known CAZymes spanning 613 carbohydrate enzyme families, covering 70.5% of all known CAZyme families. A novel multifunctional CAZyme, BfLac15, was identified, which exhibited 24.7% sequence-related similarity. Functional validation confirmed that BfLac15 can degrade both xylan and β-glucan. Conclusions: The constructed large gut microbial CAZyme library expands our knowledge of CAZymes encoded by the animal gut microbiota and provides resources to promote the development and application of CAZymes.