title: Thermophilic lignocellulose deconstruction.
abstract: Thermophilic microorganisms are attractive candidates for conversion of lignocellulose to biofuels because they produce robust, effective, carbohydrate-degrading enzymes and survive under harsh bioprocessing conditions that reflect their natural biotopes. However, no naturally occurring thermophile is known that can convert plant biomass into a liquid biofuel at rates, yields and titers that meet current bioprocessing and economic targets. Meeting those targets requires either metabolically engineering solventogenic thermophiles with additional biomass-deconstruction enzymes or engineering plant biomass degraders to produce a liquid biofuel. Thermostable enzymes from microorganisms isolated from diverse environments can serve as genetic reservoirs for both efforts. Because of the sheer number of enzymes that are required to hydrolyze plant biomass to fermentable oligosaccharides, the latter strategy appears to be the preferred route and thus has received the most attention to date. Thermophilic plant biomass degraders fall into one of two categories: cellulosomal (i.e. multienzyme complexes) and noncellulosomal (i.e. 'free' enzyme systems). Plant-biomass-deconstructing thermophilic bacteria from the genera Clostridium (cellulosomal) and Caldicellulosiruptor (noncellulosomal), which have potential as metabolic engineering platforms for producing biofuels, are compared and contrasted from a systems biology perspective.
authors.affiliation: Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA; Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
authors.forename: Sara E
authors.initials: SE
authors.lastname: Blumer-Schuette
authors.forename: Steven D
authors.initials: SD
authors.lastname: Brown
authors.forename: Kyle B
authors.initials: KB
authors.lastname: Sander
authors.forename: Edward A
authors.initials: EA
authors.lastname: Bayer
authors.forename: Irina
authors.initials: I
authors.lastname: Kataeva
authors.forename: Jeffrey V
authors.initials: JV
authors.lastname: Zurawski
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Conway
authors.forename: Michael W W
authors.initials: MW
authors.lastname: Adams
authors.forename: Robert M
authors.initials: RM
authors.lastname: Kelly
mesh_terms: D056804:Biofuels; D044603:Cellulosomes / Q000235:genetics / Q000378:metabolism; D016936:Gram-Positive Endospore-Forming Bacteria / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D006358:Hot Temperature; D008031:Lignin / Q000378:metabolism*; D008969:Molecular Sequence Data; D010944:Plants / Q000378:metabolism; D012988:Soil Microbiology
chemical_list: D056804:Biofuels; C036909:lignocellulose; D008031:Lignin
keywords: bioenergy; carbohydrate-active enzymes; cellulosome; lignocellulose deconstruction; systems biology; thermophilic microorganisms