Comparative metagenomics of cellulose- and poplar hydrolysate-degrading microcosms from gut microflora of the Canadian Beaver (Castor canadensis) and North American moose (Alces americanus) after long-term enrichment

摘要: To identify carbohydrate-active enzymes (CAZymes) that might be particularly relevant for wood fiber processing, we performed a comparative metagenomic analysis of digestive systems from Canadian beaver (Castor canadensis) and North American moose (Alces americanus) following 3 years enrichment on either microcrystalline cellulose or poplar hydrolysate. In total, 9,386 genes encoding CAZymes carbohydrate-binding modules (CBMs) were identified, with up to half predicted originate Firmicutes, Bacteroidetes, Chloroflexi, Proteobacteria phyla, 17% unknown phyla. Both PCA hierarchical cluster distinguished the annotated glycoside hydrolase (GH) distributions identified herein, those previously reported grass-feeding mammals herbivorous foragers. The CAZyme profile rumen enrichments also differed recently metagenome, most notably by absence GH13-appended dockerins. Consistent substrate-driven convergence, profiles both hydrolysate-fed cultures cellulose-fed cultures, increased numbers unique sequences belonging families GH3, GH5, GH43, GH53, CE1. Moreover, pairwise comparisons further revealed higher counts GH127 CE15 in fed expand our scope lesser known proteins, compared multi-domain proteins comprising CBM domain function (DUF) as well within 416 polysaccharide utilization loci (PULs). Interestingly, DUF362, iron-sulfur was consistently appended CBM9; other hand, PULs shared little identity unless identical PULs. Overall, this study sheds new light lignocellulose degrading capabilities microbes originating fiber-rich diets, highlights value select metagenome future biochemical characterization.