Genome Sequence and Analysis of the Soil Cellulolytic Actinomycete<i>Thermobifida fusca</i>YX

<jats:title>ABSTRACT</jats:title><jats:p><jats:italic>Thermobifida fusca</jats:italic>is a moderately thermophilic soil bacterium that belongs to<jats:italic>Actinobacteria</jats:italic>. It is a major degrader of plant cell walls and has been used as a model organism for the study of secreted, thermostable cellulases. The complete genome sequence showed that<jats:italic>T. fusca</jats:italic>has a single circular chromosome of 3,642,249 bp predicted to encode 3,117 proteins and 65 RNA species with a coding density of 85%. Genome analysis revealed the existence of 29 putative glycoside hydrolases in addition to the previously identified cellulases and xylanases. The glycosyl hydrolases include enzymes predicted to exhibit mainly dextran/starch- and xylan-degrading functions.<jats:italic>T. fusca</jats:italic>possesses two protein secretion systems: the<jats:italic>sec</jats:italic>general secretion system and the twin-arginine translocation system. Several of the secreted cellulases have sequence signatures indicating their secretion may be mediated by the twin-arginine translocation system.<jats:italic>T. fusca</jats:italic>has extensive transport systems for import of carbohydrates coupled to transcriptional regulators controlling the expression of the transporters and glycosylhydrolases. In addition to providing an overview of the physiology of a soil actinomycete, this study presents insights on the transcriptional regulation and secretion of cellulases which may facilitate the industrial exploitation of these systems.</jats:p>