title: Degradation of high loads of crystalline cellulose and of unpretreated plant biomass by the thermophilic bacterium Caldicellulosiruptor bescii.
abstract: The thermophilic bacterium Caldicellulosiruptor bescii grows at 78 °C on high concentrations (200 g L(-1)) of both crystalline cellulose and unpretreated switchgrass, while low concentrations (<20 g L(-1)) of acid-pretreated switchgrass inhibit growth. Degradation of crystalline cellulose, but not that of unpretreated switchgrass, was limited by nitrogen and vitamin (folate) availability. Under optimal conditions, C. bescii solubilized approximately 60% of the crystalline cellulose and 30% of the unpretreated switchgrass using initial substrate concentrations of 50 g L(-1). Further fermentation of crystalline cellulose and of switchgrass was inhibited by organic acid end-products and by a specific inhibitor of C. bescii growth that did not affect other thermophilic bacteria, respectively. Soluble mono- and oligosaccharides, organic acids, carbon dioxide, and microbial biomass, quantitatively accounted for the crystalline cellulose and plant biomass carbon utilized. C. bescii therefore degrades industrially-relevant concentrations of lignocellulosic biomass that have not undergone pretreatment thereby demonstrating its potential utility in biomass conversion.
authors: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA. Electronic address: mbasen@uga.edu.
authors: Mirko
authors: M
authors: Basen
authors: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA. Electronic address: rhaesa13@uga.edu.
authors: Amanda M
authors: AM
authors: Rhaesa
authors: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA. Electronic address: kataeva@uga.edu.
authors: Irina
authors: I
authors: Kataeva
authors: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA. Electronic address: cprybol1@uga.edu.
authors: Cameron J
authors: CJ
authors: Prybol
authors: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA. Electronic address: imscott357@gmail.com.
authors: Israel M
authors: IM
authors: Scott
authors: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA. Electronic address: fpoole@bmb.uga.edu.
authors: Farris L
authors: FL
authors: Poole
authors: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA. Electronic address: adams@bmb.uga.edu.
authors: Michael W W
authors: MW
authors: Adams
mesh_terms: D064751:Ammonium Compounds / Q000494:pharmacology; D001673:Biodegradation, Environmental / Q000187:drug effects; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D002482:Cellulose / Q000378:metabolism*; D005285:Fermentation / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D008031:Lignin / Q000378:metabolism; D008897:Panicum / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D013696:Temperature
chemical_list: D064751:Ammonium Compounds; C036909:lignocellulose; D002482:Cellulose; D008031:Lignin
keywords: Biomass conversion; Caldicellulosiruptor; Consolidated bioprocessing; High substrate loads; Thermophiles