title: Do rumen Bacteroidetes utilize an alternative mechanism for cellulose degradation?
abstract: Uncultured and therefore uncharacterized Bacteroidetes lineages are ubiquitous in many natural ecosystems which specialize in lignocellulose degradation. However, their metabolic contribution remains mysterious, as well-studied cultured Bacteroidetes have been shown to degrade only soluble polysaccharides within the human distal gut and herbivore rumen. We have interrogated a reconstructed genome from an uncultured Bacteroidetes phylotype that dominates a switchgrass-associated community within the cow rumen. Importantly, this characterization effort has revealed the first preliminary evidence for polysaccharide utilization locus (PUL)-catalyzed conversion of cellulose. Based on these findings, we propose a further expansion of the PUL paradigm and the saccharolytic capacity of rumen Bacteroidetes species to include cellulose, the most abundant terrestrial polysaccharide on Earth. Moreover, the perspective of a cellulolytic PUL lays the foundation for PULs to be considered an alternative mechanism for cellulose degradation, next to cellulosomes and free-enzyme systems.
authors.affiliation: Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, N-1432 Aas, Norway.
authors.forename: A E
authors.initials: AE
authors.lastname: Naas
authors.affiliation: Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, N-1432 Aas, Norway.
authors.forename: A K
authors.initials: AK
authors.lastname: Mackenzie
authors.affiliation: Department of Plant Biology and Biotechnology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Mravec
authors.affiliation: Department of Plant Biology and Biotechnology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Schückel
authors.affiliation: Department of Plant Biology and Biotechnology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: W G T
authors.initials: WG
authors.lastname: Willats
authors.affiliation: Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, N-1432 Aas, Norway.
authors.forename: V G H
authors.initials: VG
authors.lastname: Eijsink
authors.affiliation: Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, N-1432 Aas, Norway phil.pope@nmbu.no.
authors.forename: P B
authors.initials: PB
authors.lastname: Pope
mesh_terms: D000818:Animals; D041963:Bacteroidetes / Q000378:metabolism*; D002417:Cattle; D002482:Cellulose / Q000378:metabolism*; D012417:Rumen / Q000382:microbiology*
chemical_list: D002482:Cellulose
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