Genus-Wide Assessment of Lignocellulose Utilization in the Extremely Thermophilic Genus Caldicellulosiruptor by Genomic, Pangenomic, and Metagenomic Analyses.

Autor:	Lee LL; Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA., Blumer-Schuette SE; Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA., Izquierdo JA; Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA., Zurawski JV; Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA., Loder AJ; Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA., Conway JM; Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA., Elkins JG; Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA., Podar M; Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA., Clum A; DOE Joint Genome Institute, Walnut Creek, California, USA., Jones PC; Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA., Piatek MJ; Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA., Weighill DA; Bredesen Center, University of Tennessee, Knoxville, Tennessee, USA., Jacobson DA; Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA., Adams MWW; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA., Kelly RM; Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA rmkelly@ncsu.edu.
Jazyk:	angličtina
Zdroj:	Applied and environmental microbiology [Appl Environ Microbiol] 2018 Apr 16; Vol. 84 (9). Date of Electronic Publication: 2018 Apr 16 (Print Publication: 2018).
DOI:	10.1128/AEM.02694-17
Abstrakt:	Metagenomic data from Obsidian Pool (Yellowstone National Park, USA) and 13 genome sequences were used to reassess genus-wide biodiversity for the extremely thermophilic Caldicellulosiruptor The updated core genome contains 1,401 ortholog groups (average genome size for 13 species = 2,516 genes). The pangenome, which remains open with a revised total of 3,493 ortholog groups, encodes a variety of multidomain glycoside hydrolases (GHs). These include three cellulases with GH48 domains that are colocated in the glucan degradation locus (GDL) and are specific determinants for microcrystalline cellulose utilization. Three recently sequenced species, Caldicellulosiruptor sp. strain Rt8.B8 (renamed here Caldicellulosiruptor morganii ), Thermoanaerobacter cellulolyticus strain NA10 (renamed here Caldicellulosiruptor naganoensis ), and Caldicellulosiruptor sp. strain Wai35.B1 (renamed here Caldicellulosiruptor danielii ), degraded Avicel and lignocellulose (switchgrass). C. morganii was more efficient than Caldicellulosiruptor bescii in this regard and differed from the other 12 species examined, both based on genome content and organization and in the specific domain features of conserved GHs. Metagenomic analysis of lignocellulose-enriched samples from Obsidian Pool revealed limited new information on genus biodiversity. Enrichments yielded genomic signatures closely related to that of Caldicellulosiruptor obsidiansis , but there was also evidence for other thermophilic fermentative anaerobes ( Caldanaerobacter , Fervidobacterium , Caloramator , and Clostridium ). One enrichment, containing 89.8% Caldicellulosiruptor and 9.7% Caloramator , had a capacity for switchgrass solubilization comparable to that of C. bescii These results refine the known biodiversity of Caldicellulosiruptor and indicate that microcrystalline cellulose degradation at temperatures above 70°C, based on current information, is limited to certain members of this genus that produce GH48 domain-containing enzymes. IMPORTANCE The genus Caldicellulosiruptor contains the most thermophilic bacteria capable of lignocellulose deconstruction, which are promising candidates for consolidated bioprocessing for the production of biofuels and bio-based chemicals. The focus here is on the extant capability of this genus for plant biomass degradation and the extent to which this can be inferred from the core and pangenomes, based on analysis of 13 species and metagenomic sequence information from environmental samples. Key to microcrystalline hydrolysis is the content of the glucan degradation locus (GDL), a set of genes encoding glycoside hydrolases (GHs), several of which have GH48 and family 3 carbohydrate binding module domains, that function as primary cellulases. Resolving the relationship between the GDL and lignocellulose degradation will inform efforts to identify more prolific members of the genus and to develop metabolic engineering strategies to improve this characteristic. (Copyright © 2018 American Society for Microbiology.)
Databáze:	MEDLINE
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